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MATHEMATICS (645 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 538 Journals sorted alphabetically
Abakós     Open Access   (Followers: 3)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 2)
Academic Voices : A Multidisciplinary Journal     Open Access   (Followers: 2)
Accounting Perspectives     Full-text available via subscription   (Followers: 6)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Mathematical Software (TOMS)     Hybrid Journal   (Followers: 6)
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 21)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1)
Acta Mathematica     Hybrid Journal   (Followers: 10)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 5)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Decision Sciences     Open Access   (Followers: 4)
Advances in Difference Equations     Open Access   (Followers: 1)
Advances in Fixed Point Theory     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 1)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Mathematical Physics     Open Access   (Followers: 6)
Advances in Mathematics     Full-text available via subscription   (Followers: 10)
Advances in Numerical Analysis     Open Access   (Followers: 4)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Pure and Applied Mathematics     Hybrid Journal   (Followers: 5)
Advances in Pure Mathematics     Open Access   (Followers: 4)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2)
African Journal of Educational Studies in Mathematics and Sciences     Full-text available via subscription   (Followers: 5)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Afrika Matematika     Hybrid Journal   (Followers: 1)
Air, Soil & Water Research     Open Access   (Followers: 7)
AKSIOMA Journal of Mathematics Education     Open Access   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 2)
Algebra Colloquium     Hybrid Journal   (Followers: 4)
Algebra Universalis     Hybrid Journal   (Followers: 2)
Algorithmic Operations Research     Full-text available via subscription   (Followers: 5)
Algorithms     Open Access   (Followers: 9)
Algorithms Research     Open Access   (Followers: 1)
American Journal of Biostatistics     Open Access   (Followers: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
American Journal of Mathematical Analysis     Open Access  
American Journal of Mathematics     Full-text available via subscription   (Followers: 7)
American Journal of Operations Research     Open Access   (Followers: 5)
American Mathematical Monthly     Full-text available via subscription   (Followers: 6)
An International Journal of Optimization and Control: Theories & Applications     Open Access   (Followers: 7)
Analele Universitatii Ovidius Constanta - Seria Matematica     Open Access   (Followers: 1)
Analysis     Hybrid Journal   (Followers: 2)
Analysis and Applications     Hybrid Journal   (Followers: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 4)
Analysis Mathematica     Full-text available via subscription  
Annales Mathematicae Silesianae     Open Access  
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annales UMCS, Mathematica     Open Access   (Followers: 1)
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica     Open Access  
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Discrete Mathematics     Full-text available via subscription   (Followers: 6)
Annals of Mathematics     Full-text available via subscription  
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of the Alexandru Ioan Cuza University - Mathematics     Open Access  
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1)
Annals of West University of Timisoara - Mathematics     Open Access  
Annuaire du Collège de France     Open Access   (Followers: 5)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applications of Mathematics     Hybrid Journal   (Followers: 1)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Mathematics     Open Access   (Followers: 3)
Applied Mathematics     Open Access   (Followers: 4)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 4)
Applied Mathematics - A Journal of Chinese Universities     Hybrid Journal  
Applied Mathematics Letters     Full-text available via subscription   (Followers: 1)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arab Journal of Mathematical Sciences     Open Access   (Followers: 2)
Arabian Journal of Mathematics     Open Access   (Followers: 2)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 1)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
Arnold Mathematical Journal     Hybrid Journal   (Followers: 1)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 17)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asian Journal of Algebra     Open Access   (Followers: 1)
Asian Journal of Current Engineering & Maths     Open Access  
Asian-European Journal of Mathematics     Hybrid Journal   (Followers: 2)
Australian Mathematics Teacher, The     Full-text available via subscription   (Followers: 7)
Australian Primary Mathematics Classroom     Full-text available via subscription   (Followers: 2)
Australian Senior Mathematics Journal     Full-text available via subscription   (Followers: 1)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Axioms     Open Access  
Baltic International Yearbook of Cognition, Logic and Communication     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
BIBECHANA     Open Access  
BIT Numerical Mathematics     Hybrid Journal  
BoEM - Boletim online de Educação Matemática     Open Access  
Boletim Cearense de Educação e História da Matemática     Open Access  
Boletim de Educação Matemática     Open Access  
Boletín de la Sociedad Matemática Mexicana     Hybrid Journal  
Bollettino dell'Unione Matematica Italiana     Full-text available via subscription   (Followers: 1)
British Journal of Mathematical and Statistical Psychology     Full-text available via subscription   (Followers: 20)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 7)
Bulletin des Sciences Mathamatiques     Full-text available via subscription   (Followers: 4)
Bulletin of Dnipropetrovsk University. Series : Communications in Mathematical Modeling and Differential Equations Theory     Open Access   (Followers: 1)
Bulletin of Mathematical Sciences     Open Access   (Followers: 1)
Bulletin of the Brazilian Mathematical Society, New Series     Hybrid Journal  
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3)
Bulletin of the Malaysian Mathematical Sciences Society     Hybrid Journal  
Calculus of Variations and Partial Differential Equations     Hybrid Journal  
Canadian Journal of Science, Mathematics and Technology Education     Hybrid Journal   (Followers: 17)
Carpathian Mathematical Publications     Open Access   (Followers: 1)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
CHANCE     Hybrid Journal   (Followers: 5)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
ChemSusChem     Hybrid Journal   (Followers: 7)
Chinese Annals of Mathematics, Series B     Hybrid Journal  
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Mathematics     Open Access  
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Cogent Mathematics     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Collectanea Mathematica     Hybrid Journal  
College Mathematics Journal     Full-text available via subscription   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Commentarii Mathematici Helvetici     Hybrid Journal   (Followers: 1)
Communications in Contemporary Mathematics     Hybrid Journal  
Communications in Mathematical Physics     Hybrid Journal   (Followers: 1)
Communications On Pure & Applied Mathematics     Hybrid Journal   (Followers: 3)
Complex Analysis and its Synergies     Open Access   (Followers: 2)
Complex Variables and Elliptic Equations: An International Journal     Hybrid Journal  
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Comptes Rendus Mathematique     Full-text available via subscription   (Followers: 1)
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Concrete Operators     Open Access   (Followers: 4)
Confluentes Mathematici     Hybrid Journal  
COSMOS     Hybrid Journal  
Cryptography and Communications     Hybrid Journal   (Followers: 12)
Cuadernos de Investigación y Formación en Educación Matemática     Open Access  
Cubo. A Mathematical Journal     Open Access  
Czechoslovak Mathematical Journal     Hybrid Journal   (Followers: 1)
Demographic Research     Open Access   (Followers: 11)
Demonstratio Mathematica     Open Access  
Dependence Modeling     Open Access  
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 28)
Developments in Clay Science     Full-text available via subscription   (Followers: 1)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Dhaka University Journal of Science     Open Access  
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 2)
Discrete Mathematics     Hybrid Journal   (Followers: 7)
Discrete Mathematics & Theoretical Computer Science     Open Access  
Discrete Mathematics, Algorithms and Applications     Hybrid Journal   (Followers: 2)
Discussiones Mathematicae Graph Theory     Open Access   (Followers: 1)
Doklady Mathematics     Hybrid Journal  
Duke Mathematical Journal     Full-text available via subscription   (Followers: 1)
Edited Series on Advances in Nonlinear Science and Complexity     Full-text available via subscription  
Electronic Journal of Graph Theory and Applications     Open Access   (Followers: 2)
Electronic Notes in Discrete Mathematics     Full-text available via subscription   (Followers: 2)
Elemente der Mathematik     Full-text available via subscription   (Followers: 3)
Energy for Sustainable Development     Hybrid Journal   (Followers: 9)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Ensino da Matemática em Debate     Open Access  
Entropy     Open Access   (Followers: 4)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription   (Followers: 1)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 4)
European Journal of Mathematics     Hybrid Journal   (Followers: 1)
European Scientific Journal     Open Access   (Followers: 2)
Experimental Mathematics     Hybrid Journal   (Followers: 3)
Expositiones Mathematicae     Hybrid Journal   (Followers: 2)
Facta Universitatis, Series : Mathematics and Informatics     Open Access  
Fasciculi Mathematici     Open Access  
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fixed Point Theory and Applications     Open Access   (Followers: 1)
Formalized Mathematics     Open Access   (Followers: 2)
Foundations and Trends® in Econometrics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 | Last

Journal Cover Basin Research
  [SJR: 1.54]   [H-I: 60]   [3 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0950-091X - ISSN (Online) 1365-2117
   Published by John Wiley and Sons Homepage  [1583 journals]
  • Fluvial architecture in actively deforming salt basins: Chinle Formation,
           Paradox Basin, Utah
    • Authors: Adrian Hartley; Laura Evenstar
      Abstract: Determining the response of fluvial systems to syn-sedimentary halokinesis is important for reconstructing the palaeogeography of salt basins, determining the history of salt movement and predicting development and architecture of sandstone bodies for subsurface fluid extraction. To assess both the influence of salt movement on fluvial system development and the use of lithostratigraphic correlation schemes in salt basins we have analysed the Triassic Chinle Formation in the Paradox Basin, Utah.Results indicate that sandstone body development proximal to salt bodies should be considered at two scales: intra- (local) and inter- (regional) mini-basin scale. At the intra-mini basin or local scale, conformable packages up to 12 m of deep meandering fluvial channel deposits and associated overbank deposits are developed, which may thin, pinch-out or become truncated towards salt highs. When traced down the axis of a mini-basin, individual stories extend for a few hundred metres, and form part of amalgamated channel-belt packages up to 60 m thick that can be traced for at least 25 km parallel to palaeoflow. Where salt movement outpaces sediment accumulation, progressive low angle unconformities are developed along the flanks of salt highs. Significantly, in mini-basins with high sand supply, sandstone bodies are present across salt highs where they show increased amalgamation, decrease in thickness due to truncation and no change in internal sandstone body character.At inter mini-basin or regional scale, spatial and temporal variations in accommodation space generated by differential salt movement strongly influence facies distributions and facies correlation lengths. Broad lithostratigraphic packages (5 to 50 m thick) can be correlated within mini-basins, but correlation of these units between adjacent mini-basins is problematic. Knowledge of fluvial system development at a regional scale is critical as, fluvial sediment distribution is focussed by topography generated by growing salt bodies, such that adjacent mini-basins can have significant differences in sandstone body thickness, distribution and lateral extent.The observations from the Chinle Formation indicate that lithostratigraphic-based correlation schemes can only be applied within mini-basins and cannot be used to correlate between adjacent mini-basins or across a salt mini-basin province. The key to predicting sandstone body development is an understanding of the timing of salt movement and reconstructing fluvial drainage system development.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-17T15:45:26.854057-05:
      DOI: 10.1111/bre.12247
  • Fracturing and fluid flow during post-rift subsidence in carbonate of the
           Jandaíra Formation, Potiguar Basin, NE Brazil
    • Authors: Giovanni Bertotti; Stefan de Graaf, Kevin Bisdom, Brigit Oskam, Hubert Vonhof, Francisco Hilario Bezerra, John Reijmer, Caroline Cazarin
      Abstract: Pervasive fracture networks are common in many reservoir-scale carbonate bodies even in the absence of large deformation and exert a major impact on their mechanical and flow behavior. The Upper Cretaceous Jandaíra Formation is a few hundred meters thick succession of shallow water carbonates deposited during the early post-rift stage of the Potiguar rift (NE Brazil). The Jandaíra Formation in the present onshore domain experienced 1000 km2. The carbonates have a gentle, 400-500 m. Deformation was accommodated by a dense network of sub-vertical mode I and hybrid fractures associated with sub-vertical stylolites developed in a stress field characterized by a sub-horizontal σ1 and sub-vertical σ2. The development of a network of hybrid fractures, rarely reported in the literature, activated the circulation of waters charged in the mountainous region, flowing along the porous Açu sandstone underlying the Jandaíra carbonates and rising to the surface through the fractured carbonates. With persisting subsidence, carbonates reached depths of 800-900 m entering a depth interval characterized by a sub-vertical σ1. At this stage, sub-horizontal stylolites developed liberating calcite which sealed the sub-vertical open fractures transforming them in veins and preventing further flow. During Tertiary exhumation, pre-existing veins and stylolites were opened and became longer, and new fractures were created typically with the same directions of the older features. The simplicity of our model and findings suggest that most rocks in passive margin settings might have followed a similar evolution and thus display similar structures.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T09:15:30.126827-05:
      DOI: 10.1111/bre.12246
  • Visualizing, interpreting and comparing detrital zircon age and Hf isotope
           data in basin analysis - a graphical approach
    • Authors: Tom Andersen; Magnus Kristoffersen, Marlina A. Elburg
      Abstract: The development of fast and reliable instrumental methods for U-Pb dating and Lu-Hf isotope analysis of zircon has caused detrital zircon to become a popular provenance indicator for clastic sediments and an important tool in basin analysis. In parallel with the increasing ease of access to data, advanced methods of data interpretation have been developed. The downside of some techniques for visualization and comparison of detrital zircon distribution patterns is that the results are difficult to relate to what the zircon grains really record: The age and nature of geological processes in a protosource terrane. Some simple methods of data presentation and inter-sample comparison that preserve a direct and intuitively understandable relationship between the data and the age of zircon-forming processes in the protosource are proposed here: Comparison of confidence intervals around empirical, cumulative distribution curves combined with the use of a plot of upper vs. lower quartile values of cumulative zircon U-Pb age or Lu-Hf model age distributions. This approach allows a robust and transparent separation to be made between samples whose detrital zircon distributions are indistinguishable from each other, and those that are more or less similar. Furthermore, it allows simple comparison between detrital zircon distributions and the geological age record of potential protosource terranes, or the detrital zircon distributions of possible sedimentary precursors.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T03:01:31.377965-05:
      DOI: 10.1111/bre.12245
  • Changes in Cenozoic depositional environment and sediment provenance in
           the Danube Basin
    • Authors: Michal Kováč; Samuel Rybár, Eva Halásová, Natália Hudáčková, Katarína Šarinová, Michal Šujan, Victoria Baranyi, Marianna Kováčová, Andrej Ruman, Tomáš Klučiar, Adriena Zlinská
      Abstract: The Danube Basin is situated between the Eastern Alps, Western Carpathians and Transdanubian mountain ranges and represents a classic petroleum prospection site. The basin fill is known from many 2D reflection seismic lines and deep wells with measured e-logs which provided a good opportunity for theories about its evolution. New analyses of deep wells situated in the Danube Basin northeastern margin allowed us to refine stratigraphy and to interpret various depositional systems. This also allowed us to outline changes in provenance of sediment during the Cenozoic. The performed interpretation of the Paleogene and Neogene depositional systems also confirmed the Oligocene-NDASH-Early Miocene exhumation of the basin pre-Neogene basement. Opening and development of the Middle to Late Miocene basin depocentres above the boundary between the Western Carpathians and Northern Pannonian domain was recognized. Our analysis contributed to a better understanding of the Hurbanovo-NDASH-Diösjenő fault which acts as an inherited weakness zone along the boundary of two crustal fragments with different provenance. We document various basin types stacked one on another (retro-arc, back-arc, and extensional hinterland basin). The analysis of sediment sources reveals intricate geodynamic processes during the Eastern Alpine-NDASH-Western Carpathian orogenic system collision with European platform (formation of ALCAPA microplate) and its successive tectonics escape during the Pannonian Basin System origination.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T15:52:08.276083-05:
      DOI: 10.1111/bre.12244
  • Tectonic uplift of the Xichang Basin (SE Tibetan Plateau) revealed by
           structural geology and thermochronology data
    • Authors: Bin Deng; Shugen Liu, Lei Jiang, Gaoping Zhao, Rui Huang, Zhiwu Li, Jinxi Li, Luba Jansa
      Abstract: The Xichang Basin in southeastern Tibet provides crucial information about formation and tectonic processes affecting the eastern Tibetan Plateau. To determine when and how the uplift developed, we conducted detailed studies of structures and obtained thermochronology data from the Xichang Basin and its periphery. The Xichang Basin is characterized by gentle deformation of the strata, segmented by an E-vergent boundary thrust fault. Two stages of deformation, strike-slip followed by an E-W oriented shortening resulted in oblique shortening between the southeastern Tibetan Plateau and the Sichuan Basin. New apatite fission track data interpreted together with (U-Th)/He data confirm a simple burial/heating and exhumation/cooling history across the Xichang Basin and its periphery. Subsidence and burial of the Xichang Basin peaked between 80~30 Ma, followed by mountain building with a protracted cooling starting at around 40-20 Ma, with rates of ~2.0-8.0 °C/Myr (i.e., 0.1-0.3 mm/yr). Our data indicate that the Xichang Basin has experienced ~2.5-5 km of exhumation, much more intensive than the ~1-2 km of exhumation inferred for the southwestern Sichuan Basin. Restored balanced cross-sections of post-Late-Triassic strata along a ~250 km traverse indicate ~10-20% east-west shortening strain (i.e., ~20-30 km) at the southeastern Tibetan Plateau during Cenozoic time. Study of crustal thickening and erosion supports a tectonic shortening mechanism to account for the uplift of the Xichang Basin on the southeastern Tibetan Plateau.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T19:10:22.208406-05:
      DOI: 10.1111/bre.12243
  • Weathering regime in the Eastern Himalaya since the mid-Miocene:
           Indications from detrital geochemistry and clay mineralogy of the Kameng
           River Section, Arunachal Pradesh, India
    • Authors: Natalie Vögeli; Pascale Huyghe, Peter van der Beek, Yani Najman, Eduardo Garzanti, Catherine Chauvel
      Abstract: It is crucial to understand lateral differences in paleo-climate and weathering in order to fully understand the evolution of the Himalayan mountain belt. While many studies have focused on the western and central Himalaya, the eastern Himalaya remains poorly studied with regard to paleoclimate and past weathering history. Here we present a multi-proxy study on the Mio-Pliocene sedimentary foreland-basin section along the Kameng River in Arunachal Pradesh, northeast India, in order to obtain better insight in the weathering history of the eastern Himalaya. We analyzed a continuous sedimentary record over the last 13 Ma. Heavy-mineral and petrography data give insight into diagenesis and provenance, showing that the older part of the section is influenced by diagenesis and that sediments were not only deposited by a large Trans-Himalayan river and the palaeo-Kameng river, but also by smaller local tributaries. By taking into account changes in diagenesis and provenance, results of clay mineralogy and major element analysis show an overall increase in weathering intensity over time, with a remarkable change between ~10 and ~8 Ma.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T08:05:39.145566-05:
      DOI: 10.1111/bre.12242
  • Cenozoic evolution of the Altyn Tagh and East Kunlun fault zones inferred
           from detrital garnet, tourmaline and rutile in southwestern Qaidam Basin
           (Northern Tibetan Plateau)
    • Authors: Li Linlin; Wu Chaodong, Yu Xiangjiang
      Abstract: This study focuses on the Cenozoic provenance and tectonic evolution of the southwestern Qaidam Basin through geochemical analysis of detrital garnet, tourmaline and rutile. The variation of detrital mineral compositions indicates that the Cenozoic evolution can be divided into 3 stages: 1) before the deposition of the upper Xiaganchaigou Formation (before 37.8 Ma); 2) between the deposition of the upper Xiaganchaigou Formation and the Shangganchaigou Formation (from 37.8 Ma to 22 Ma); 3) since the deposition of the Xiayoushashan Formation (since 22 Ma). In the first stage, abundant garnets from high-grade meta-basic and ultramafic rocks in the sediments from the Ganchaigou area support a provenance from the South Altyn Tagh HP/UHP metamorphic zone. The low percentage of tourmalines from granitoid rocks in the sediments in the Kunbei-Lücaotan area suggests a provenance from the East Kunlun fault zone, indicating that the Qimen Tagh Shan was not high enough to prevent the transport of sediments from the southern Qaidam Basin. The sediments in the Qigequan area were derived from both the Altyn Tagh fault zone and the East Kunlun fault zone. In the second stage, the tectonic activity consisted in the rapid uplift of the Altyn Shan. Changes in garnet composition indicate a lower detrital contribution from high-grade metamorphic rocks. In the third stage, the disappearance of garnets from high-grade metamorphic rocks and scattered temperatures of rutiles in the Ganchaigou area suggest that the source area shifted from the South Altyn Tagh HP/UHP metamorphic rocks to weakly metamorphosed Meso-Neoproterozoic sedimentary rocks. The increase in granitoid-derived tourmalines in the Kunbei-Lücaotan area is indicative of the rapid uplift of the Qimen Tagh Shan. The provenance evolution in the southwestern Qaidam Basin indicates that the tectonic activity along the Altyn Tagh fault zone can be divided into an early stage of Altyn Shan uplift and a later stage of left-lateral slip. At the same time, tectonic movement along the East Kunlun fault zone initiated.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-02T07:21:13.351634-05:
      DOI: 10.1111/bre.12241
  • The role of fault length, overlap and spacing in controlling extensional
           relay ramp fluvial system geometry
    • Authors: Michael C. Hopkins; Nancye H. Dawers
      Abstract: Relay ramps are integral components of normal fault systems that control sediment transport pathways in evolving rifts. We attribute differences in the geometry of fluvial systems that drain relay ramps to the scale of the ramp bounding fault segments, the spacing between segments and the amount of overlap between segments. Previous conceptual models for relay ramp geomorphological evolution have assumed that ramp fluvial catchments develop on the ramp surfaces and flow parallel to fault strike into the adjacent basin. Numerous examples exist in nature, however, that show that this is not ubiquitous. The fundamental question of what drives differences in fluvial geometry in these settings has, to date, not been fully addressed. We selected 27 relay ramps across the Basin and Range, western North America, and mapped, via GPS and remote sensing, the faults and ramp fluvial systems associated with each site. The sites represent a range of fault scales, which we define by the total outboard fault length, and a range of spacing and overlap values in order to better understand the structural controls on differences among ramp fluvial systems. Results show that the majority of a relay ramp surface drains parallel to fault strike when the outboard fault is less than about 15 km long. High overlap/spacing ratios are associated with relays along shorter (< 15 km long) outboard faults, whereas lower overlap/spacing ratios are associated with relays along longer faults. Relays with lower overlap/spacing values may be more common along longer outboard faults because they survive for longer periods of time in the landscape. Our geomorphological observations can be used to predict synrift depocenter locations along segmented faults, but these observations only apply if the faults are short (
      PubDate: 2017-03-23T06:15:33.726704-05:
      DOI: 10.1111/bre.12240
  • New insights in the development of syn-depositional fractures in rimmed
           flat-topped carbonate platforms, Neogene carbonate complexes, Sorbas
           Basin, SE Spain
    • Authors: Casimir W. Nooitgedacht; Lucas M. Kleipool, Bernd Andeweg, Jesús Reolid, Christian Betzler, Sebastian Lindhorst, John J.G. Reijmer
      Abstract: The formation of syn-depositional fractures in carbonate platforms is considered an important feature in the understanding of platform evolution. This study investigates the mechanisms of fracture formation in rimmed flat-topped carbonate platforms in the very well exposed Cariatiz Miocene Fringing Reef Unit, SE Spain. Fracture data were obtained using a combination of LIDAR and field mapping techniques, which proved useful in understanding general fracture trends. The morphological expression of fracture sets, preferred fracture localisation, crosscutting relationships and fracture fill are characteristics that provide constraints on the timing of fracture formation and opening. Three dominant fracture populations were identified, amongst which a margin parallel and a margin perpendicular fracture set. Margin parallel fractures localise around the platform margin and form vertically extensive dikes that crosscut facies boundaries. The sedimentary fill of such fractures suggests syn-depositional fracture formation under marine conditions. Together, fracture characteristics suggest a gravitational driver for the formation of tensile stress and the development of margin parallel fractures along the platform edge. Margin perpendicular structures form sub-vertical dikes and fracture corridors. Margin perpendicular fractures localise on the platform slope and show two types of fracture fill, indicating marine and continental origins. Based on variations of fracture morphology along the carbonate platform, fracture localisation, petrographic analysis of sedimentary fill and stable isotope analysis on sparite cements, we suggest a gravitational control on the formation of these fractures. Two mechanisms for the formation of subvertical margin perpendicular fractures are proposed: (1) principal stress rotation as a result of downslope loading. (2) Differential compaction over buried gulley systems on antecedent clinoform slopes. We suggest that the formation of sub-vertical margin perpendicular fractures might be a systematic feature in slopes of flat-topped carbonate platforms.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-16T10:35:43.927426-05:
      DOI: 10.1111/bre.12239
  • Paleo-fluid expulsion and contouritic drift formation on the Chatham Rise,
           New Zealand
    • Authors: Kate Alyse Waghorn; Ingo Pecher, Lorna J. Strachan, Gareth Crutchley, Jörg Bialas, Richard Coffin, Bryan Davy, Stephanie Koch, Karsten F. Kroeger, Cord Papenberg, Sudipta Sarkar,
      Abstract: The Chatham Rise is located offshore of New Zealand's South Island. Vast areas of the Chatham Rise are covered in circular to elliptical seafloor depressions that appear to be forming through a bathymetrically controlled mechanism, as seafloor depressions 2–5 km in diameter are found in water depths of 800–1100 m. High-resolution P-Cable 3D seismic data were acquired in 2013 across one of these depressions. The seafloor depression is interpreted as a mounded contourite. Our data reveal several smaller buried depressions (
      PubDate: 2017-03-16T03:36:56.017197-05:
      DOI: 10.1111/bre.12237
  • Burial and exhumation of the western border of the Ukrainian Shield
           (Podolia): a multi-disciplinary approach
    • Authors: Andrea Schito; Benedetta Andreucci, Luca Aldega, Sveva Corrado, Lea Di Paolo, Massimiliano Zattin, Rafal Szaniawski, Leszek Jankowski, Stefano Mazzoli
      Abstract: The Podolia region is located along the western border of the Eastern European Craton, which is also known as Ukrainian Shield. From the Ordovician to the Miocene, this area formed part of an epicontinental basin system. In order to investigate the effects of orogenic cycles occurring along the plate margin, a multi-disciplinary approach was used in this study. Paleotemperature analysis and low-temperature thermochronometry were combined with stratigraphic data to obtain a burial model for the Paleozoic succession exposed in the study area. Maximum burial for Silurian and Devonian rocks occurred during the Devonian and Early Carboniferous at depths of 4–5 km, as constrained by vitrinite reflectance and illite content in mixed illite-smectite layers. Thermochronometric data indicate that exhumation through the 45–120 °C temperature range took place between the Late Triassic and the Early Jurassic, and that no significant burial occurred afterwards (temperatures characterising the stratigraphically lowermost units remaining below ca. 60 °C). These results point to a major exhumation event coeval with the Cimmerian orogenesis, which took place a few hundreds of kilometres away from the study area. On the other hand, no significant effect of the Alpine orogenesis was recorded, although the collisional front was located
      PubDate: 2017-03-14T23:05:43.052729-05:
      DOI: 10.1111/bre.12235
  • The drowning of a siliciclastic shelf: insights into oceanographic
           reconstructions of the northern Arabian Platform during the Early
    • Authors: Or M. Bialik; Nicolas Waldmann
      Abstract: Barremian-Aptian sedimentary successions along the northern Arabian margin have been described as a transition from a siliciclastic to a carbonate-dominated marine environment, deposited upon a low-relief shelf or platform formed as a consequence of continuous regional subsidence. A long (360 m) core from northern Israel offers a unique look at this transition, providing valuable insights for the palaeoceanography, geometry and ventilation conditions that lead to Oceanic Anoxic Event 1 (OAE1) in this region. Results from high-resolution elemental, mineralogical, sedimentological and petrophysical analyses carried out revealed the emplacement of abundant mass-transport deposits (MTDs) during the Late Barremian and the Aptian. The transplanted units are characterized by fine grained calcareous shales with elevated organic matter, sulphur and iron contents. The scarcity or absence of bioturbation in the disturbed sequences provides a hint to the sediment/water interface conditions. However, a decrease in sulphur and iron occurring at the contact between the shales and the MTDs is explained as increased oxic conditions at the sediment-water interface as a result of turbulence and mixing associated with the descending sediment masses. Such recurrent events ventilation of the low-energy basinal environment during the Late Barremian and Aptian, predate the wide-scale establishment of OAE1 in the northern Arabian margin. Moreover, the identification of coarse-grained MTDs within deep-water calcareous sediments indicates a much steeper gradient of the northern Arabian margin, challenging previous studies.
      PubDate: 2017-03-05T23:20:45.144681-05:
      DOI: 10.1111/bre.12234
  • Sequence Architecture and Depositional Evolution of the Northern
           Continental Slope of the South China Sea: Responses to Tectonic Processes
           and Changes in Sea Level
    • Authors: Changsong Lin; Jing Jiang, Hesheng Shi, Zhongtao Zhang, Jingyan Liu, Qin Chenggang, Hao Li, Huaijiang Ran, An Wei, Hongxun Tian, Zuochang Xing, Qingyu Yao
      Abstract: The continental slopes of the South China Sea (SCS), the largest marginal sea on the continental shelf of Southeast Asia, are among the most significant shelf-margin basins in the world because of their abundant petroleum resources and a developmental history related to sea floor spreading since Late Oligocene time. Based on integrated analyses of seismic, well-logging and core data, we systematically document the sequence architecture and depositional evolution of the northern continental slope of the SCS and reveal its responses to tectonism, sea-level change and sediment supply. The infill of this shelf-margin basin can be divided into seven composite sequences (CS1‒CS7) that are bounded by regional unconformities. Composite sequences CS3 to CS7 have formed since Late Oligocene time, and each of them generally reflects a regional transgressive–regressive cycle. These large cycles can be further divided into 20 sequences that are defined by local unconformities or transgressive–regressive boundaries. Depositional–geomorphologic systems represented on the continental slope mainly include shelf-edge deltas, prodelta-slope fans, clinoforms of the shelf-margin slope, unidirectionally migrating slope channels, incised slope valleys, muddy slope fans, slope slump-debris-flow complexes, and large-scale soft-sediment deformation of bedding. Changing sea levels, reflected by evidence from sequence architecture in the study area, are generally comparable with those of the Haq (1987) global sea level curve, whereas the regional transgressions and regressions were apparently controlled by tectonic uplift and subsidence. Composite sequences CS3 and CS4 formed from Late Oligocene to Middle Miocene time and represent continental-slope deposition during a time of northwest-northeast seafloor spreading and subsequent development of sub-basins in the southwest-central SCS. The development of composite sequences CS5 to CS7 after Middle Miocene time was obviously influenced by the Dongsha Movement during convergence between the SCS and Philippine Sea plates. Climatic variations and monsoon intensification may have enhanced sediment supply during Late Oligocene‒Early Miocene (25-21 Ma) and Late Pliocene‒Pleistocene (3-0.8 Ma) times. This study indicates that shelf-edge delta and associated slope fan systems are the most important oil/gas-bearing reservoirs in the SCS continental-slope area.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-17T01:55:54.439773-05:
      DOI: 10.1111/bre.12238
  • Terrace formation in the upper Bengal basin since the middle pleistocene:
           Brahmaputra fan delta construction during multiple highstands
    • Authors: Jennifer L. Pickering; Steven L. Goodbred, Jeremiah C. Beam, John C. Ayers, Aaron K. Covey, Haresh M. Rajapara, Ashok K. Singhvi
      Abstract: Floodplains, paleosols, and antecedent landforms near the apex of the Brahmaputra fan delta in north-central Bangladesh preserve cycles of fluvial sediment deposition, erosion, and weathering. Together these landforms and their associated deposits comprise morphostratigraphic units that define the river's history and have influenced its channel position and avulsion behavior through the Late Quaternary. Previously, temporal differentiation within these units has not been sufficient to decipher their sequence of deposition, an important step in understanding the spatial pattern of migration of the Brahmaputra River. Holocene units in this region are fairly well established by radiocarbon dating of in situ organic material, but pre-Holocene units are considered Pleistocene-aged if organic material is dated> 48000 yr BP (the limit of radiocarbon dating) or the sediments are positioned beneath a prominent paleosol, interpreted as a buried soil horizon that developed during a previous sea level lowstand. In such cases, these morphostratigraphic units have been broadly interpreted as Pleistocene without knowing their absolute depositional ages or relative evolutionary chronology. Here we use detailed sediment analysis to better differentiate morphostratigraphic units at the Brahmaputra's avulsion node, establishing the sequence of deposition and subsequent weathering of these bodies. We then test this relative chronology by luminescence dating of the sands beneath these landform surfaces. This work provides the first absolute depositional age constraints of terrace sediments for the Middle to Late Pleistocene Brahmaputra River and upper Bengal basin. The luminescence ages are complemented by detailed compositional trends in the terraces deposits, including clay mineralogy and the degree of weathering. Together, these newly dated and carefully described morphostratigraphic units reflect eustasy-driven cycles of terrace development by way of highstand floodplain deposition and subsequent lowstand exposure and weathering, along with active tectonic deformation. Defining this Late Quaternary history of terrace development and position of the Brahmaputra River is a first step toward an integrated understanding of basin and delta evolution over multiple glacioeustatic cycles and tectonically relevant timescales.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-09T07:05:28.747195-05:
      DOI: 10.1111/bre.12236
  • Tectonic compaction shortening in toe region of isolated listric normal
           fault, North Taranaki Basin, New Zealand
    • Authors: Chris K. Morley; Diako Hariri Naghadeh
      Abstract: Industry 2D and 3D seismic data across the North Taranaki Basin displays two listric normal faults that formed during Pliocene shelf edge clinoform progradation. The faults die out in the down-transport direction with no evidence for contractional structures, except for two small thrust faults in one narrow zone. When active, the detachments lay at depths of about 1000 m below the seafloor. The overlying section had high initial porosities (30–60%). It is estimated that loss of about 17–20% pore volume by lateral compaction, and fluid expulsion over a distance of about 4–6 km in the transport direction occurred in place of folding and thrusting. Seismic and well evidence for abnormally highly compacted shales suggests there is about 6% less porosity than expected for in the prekinematic section, which possibly represents a residual of the porosity anomaly caused by lateral compaction. The observations indicate significant shortening (~20%) by lateral compaction and probably some layer parallel thickening are important deformation mechanisms in near-surface deepwater sediments that needs to be incorporated into shortening estimates and ‘balanced’ cross-sections. A key factor in listric fault initiation near the base of slope is inferred to be transient, increased pore fluid pressure due to lateral expulsion of fluids from beneath the prograding Giant Foresets Formation.
      PubDate: 2017-02-01T06:51:14.607729-05:
      DOI: 10.1111/bre.12227
  • Application of multi-kinetic apatite fission track and (U-Th)/He
           thermochronology to source rock thermal history: A case study from the
           Mackenzie Plain, NWT, Canada
    • Authors: Jeremy Powell; David Schneider, Dale Issler
      Abstract: Shale of the Upper Cretaceous Slater River Formation extends across the Mackenzie Plain of the Canadian Northwest Territories and has potential as a regional source rock due to the high organic content and presence of both oil- and gas-prone kerogen. An understanding of the thermal history experienced by the shale is required to predict any potential petroleum systems. Our study integrates multi-kinetic apatite fission track (AFT) and apatite (U-Th)/He (AHe) thermochronometers from a basal bentonite unit to understand the timing and magnitude of Late Cretaceous burial experienced by the Slater River Formation along the Imperial River. We use LA-ICP-MS and EPMA methods to assess the chemistry of apatite, and use these values to derive the AFT kinetic parameter rmr0. Our AFT dates and track lengths, respectively, range from 201.5 ± 36.9 Ma to 47.1 ± 12.3 Ma, and 16.8 to 10.2 μm, and single crystal AHe dates are between 57.9 ± 3.5 and 42.0 ± 2.5 Ma with effective uranium concentrations from 17.3 ppm to 35.6 ppm. The fission track data show no relationship with the kinetic parameter Dpar and fail the χ2 test indicating that the data do not comprise a single statistically significant population. However, when plotted against their rmr0 value, the data are separated into two statistically significant kinetic populations with distinct track length distributions. Inverse thermal history modeling of both the multi-kinetic AFT and AHe datasets, reveal that the Slater River Formation reached maximum burial temperatures of ~65-90°C between the Turonian and Paleocene, indicating that the source rock matured to the early stages of hydrocarbon generation, at best. Ultimately, our data highlight the importance of kinetic parameter choice for AFT and AHe thermochronology, as slight variations in apatite chemistry may have significant implications on fission track and radiation damage annealing in apatite with protracted thermal histories through the uppermost crust.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-01T01:51:07.516727-05:
      DOI: 10.1111/bre.12233
  • Sedimentary environment evolution in a marine hangingwall dipslope
           setting. El Qaa Fault Block, Suez Rift, Egypt
    • Authors: Martin Muravchik; Rob L. Gawthorpe, Ian R. Sharp, Franklin Rarity, David Hodgetts
      Abstract: Sedimentation in hangingwall dipslope settings is still a relatively underexplored topic in rift basin studies. A better understanding of the evolution of marine sedimentary environments in this kind of settings has to address the variations occurring both along the strike and down the dipslope. Previous work was mainly built on the analysis of subsurface data, relying on the visualization of coarse resolution (10s of m) seismic sections and sparsely located borehole logs (km apart). This study focuses on the sedimentology and stratal arrangement of excellent quality Miocene marine early syn-rift and rift climax successions continuously exposed for more than 20 km along the strike of the hangingwall dipslope in the El Qaa Fault Block, Suez Rift, Egypt. The integration of traditional sedimentary field techniques and terrestrial LIDAR scanning allowed for a detailed analysis of dip and dip direction for the different depositional units. Three different phases of tilting were identified for the hangingwall dipslope, which controlled the overall evolution of the marine sedimentary environment in the area. The tilt of the hangingwall not only determined variations in facies, thickness and grain-size of the deposits down the dipslope but also along its strike. The studied exposures of the El Qaa Fault Block dipslope constitute a unique outcrop analogue for marine sedimentation in hangingwall dipslopes.
      PubDate: 2017-01-24T00:21:36.304821-05:
      DOI: 10.1111/bre.12231
  • An integrated model of clastic injectites and basin floor lobe complexes:
           implications for stratigraphic trap plays
    • Authors: Sarah Louise Cobain; David Mark Hodgson, Jeff Peakall, Michelle Nicole Shiers
      Abstract: Injectites sourced from base-of-slope and basin-floor parent sandbodies are rarely reported in comparison to submarine slope channel systems. This study utilizes the well-constrained palaeogeographic and stratigraphic context of three outcrop examples exposed in the Karoo Basin, South Africa, to examine the relationship between abrupt stratigraphic pinchouts in basin-floor lobe complexes, and the presence, controls, and character of injectite architecture. Injectites in this palaeogeographic setting occur where there is: (i) sealing mudstone both above and below the parent sand to create initial overpressure; (ii) an abrupt pinchout of a basin-floor lobe complex through steep confinement to promote compaction drive; (iii) clean, proximal sand beds aiding fluidization; and (iv) a sharp contact between parent sand and host lithology generating a source point for hydraulic fracture and resultant injection of sand. In all outcrop cases, dykes are orientated perpendicular to palaeoslope, and the injected sand propagated laterally beneath the parent sand, paralleling the base to extend beyond its pinchout. Understanding the mechanisms that determine and drive injection is important in improving the prediction of the location and character of clastic injectites in the subsurface. Here, we highlight the close association of basin-floor stratigraphic traps and sub-seismic clastic injectites, and present a model to explain the presence and morphology of injectites in these locations.
      PubDate: 2017-01-20T00:27:34.857947-05:
      DOI: 10.1111/bre.12229
  • Geological controls on the present temperature field of the western
           Sverdrup Basin, Canadian Arctic Archipelago
    • Authors: Zhuoheng Chen; Stephen E. Grasby, Keith Dewing, Kirk G. Osadetz, Tom Brent
      Abstract: Analysis of current temperature data in the Canadian Arctic Archipelago results in the recognition of two major thermal regimes. High temperature regions are observed where salt diapirs and salt cored anticlines are present. Low temperature fields are observed along the western and southern basin margins and around Cornwall-Amund Ringnes islands, where regional Mesozoic aquifers are exposed to surface, connected to basin boundary faults, or regional unconformities. Meteoric and Holocene sub-glacial water recharge are inferred to be responsible for the low geothermal regime and low formation water salinity. Neither exhumation associated with the Eocene “Eurekan” orogeny nor volcanic intrusion associated with opening of Amerasia Basin in late Jurassic-early Cretaceous have been interpreted to be a significant influence on the present day temperature field, although thermal indicators show evidence of elevated thermal alteration of organic matter pointing to earlier, but now dissipated, thermal anomalies.
      PubDate: 2017-01-20T00:27:18.049369-05:
      DOI: 10.1111/bre.12232
  • The architecture of submarine monogenetic volcanoes – insights from
           3D seismic data
    • Authors: Peter Reynolds; Nick Schofield, Richard J. Brown, Simon Paul Holford
      Abstract: Many prospective sedimentary basins contain a variety of extrusive volcanic products that are ultimately sourced from volcanoes. However, seismic reflection-based studies of magmatic rift basins have tended to focus on the underlying magma plumbing system, meaning that the seismic characteristics of volcanoes are not well understood. Additionally, volcanoes have similar morphologies to hydrothermal vents, which are also linked to underlying magmatic intrusions. In this study, we use high resolution 3D seismic and well data from the Bass Basin, offshore southern Australia, to document 34 cone- and crater-type vents of Miocene age. The vents overlie magmatic intrusions and have seismic properties indicative of a volcanic origin: their moderate–high amplitude upper reflections and zones of “wash-out” and velocity pull-up beneath. The internal reflections of the vents are similar to those found in lava deltas, suggesting they are composed of volcaniclastic material. This interpretation is corroborated by data from exploration wells which penetrated the flanks of several vents. We infer that the vents we describe are composed of hyaloclastite and pyroclasts produced during submarine volcanic eruptions. The morphology of the vents is typical of monogenetic volcanoes, consistent with the onshore record of volcanism on the southern Australian margin. Based on temporal, spatial and volumetric relationships, we propose that submarine volcanoes can evolve from maars to tuff cones as a result of varying magma-water interaction efficiency. The morphologies of the volcanoes and their links to the underlying feeder systems are superficially similar to hydrothermal vents. This highlights the need for careful seismic interpretation and characterization of vent structures linked to magmatic intrusions within sedimentary basins.
      PubDate: 2017-01-20T00:27:05.023437-05:
      DOI: 10.1111/bre.12230
  • Magnetostratigraphy, age and depositional environment of the Lobo
           Formation, southwest New Mexico: implications for the Laramide orogeny in
           the southern Rocky Mountains
    • Authors: Marie G. De los Santos; Timothy F. Lawton, Peter Copeland, Alexis Licht, Stuart A. Hall
      Abstract: The Lobo Formation of southwestern New Mexico consists of spatially variable continental successions attributed to the Laramide orogeny (80–40 Myr), although its age and provenance are virtually undocumented. This study combines sedimentological, magnetostratigraphical and geochronological data to infer the timing and origin of the Lobo Formation. Measured sections of Lobo strata at two locations, Capitol Dome in the Florida Mountains and in the Victorio Mountains, indicate significant differences in depositional environments and sediment provenance. At Capitol Dome, where Lobo strata were deposited above a syncline developed in Palaeozoic strata, deposition took place in fluvial, palustrine and marginal lacustrine settings, with alluvial-fan deposits only at the top of the formation. Combined magnetostratigraphy and a young U–Pb detrital zircon age suggest deposition of the section at Capitol Dome from ~60 to 52 Ma. The Lobo Formation in the Victorio Mountains was deposited in alluvial-fan and fluvial settings; the age of deposition is poorly bracketed between 66 ± 2 Ma, the weighted-mean age of two young zircons, and middle Eocene (~40 Ma), the approximate age of overlying volcanic rocks. U–Pb zircon ages from sandstones at the Victorio and Capitol Dome localities indicate that different source rocks provided sediment to the Lobo Formation. Local Proterozoic basement (~1.47–1.45 Ga) dominated the source of the Lobo Formation in the Victorio Mountains, consistent with abundant granitic clasts that are present in the proximal facies there; a diverse range of grain ages suggest that recycled Lower Cretaceous strata provided the dominant source for Lobo Formation sediment at the Capitol Dome locality. The U–Pb data suggest that the depositional systems at the two sites were not connected. Contrasts in depositional setting and detrital zircon provenance indicate that the Palaeogene Lobo Formation in southwest New Mexico was deposited in an assemblage of local depositional settings, possibly in separate structural basins, as a consequence of Laramide tectonics in the region.
      PubDate: 2016-12-27T08:06:22.110909-05:
      DOI: 10.1111/bre.12226
  • Jurassic rifting to post-rift subsidence analysis in the Central High
           Atlas and its relation to salt diapirism
    • Authors: Mar Moragas; Jaume Vergés, Eduard Saura, Juan-Diego Martín-Martín, Grégoire Messager, Óscar Merino-Tomé, Isabel Suárez-Ruiz, Philippe Razin, Carine Grélaud, Manon Malaval, Rémi Joussiaume, David William Hunt
      Abstract: The subsidence evolution of the Tethyan Moroccan Atlas Basin, presently inverted as the Central High Atlas, is characterized by an Early Jurassic rifting episode, synchronous with salt diapirism of the Triassic evaporite-bearing rocks. Two contrasting regions of the rift basin – with and without salt diapirism – are examined to assess the effect of salt tectonics in the evolution of subsidence patterns and stratigraphy. The Djebel Bou Dahar platform to basin system, located in the southern margin of the Atlas Basin, shows a Lower Jurassic record of normal faulting and lacks any evidence of salt diapirism. In contrast, the Tazoult ridge and adjacent Amezraï basin, located in the centre of the Atlas Basin, reveals spectacular Early Jurassic diapirism. In addition, we analyse alternative Central High Atlas post-Middle Jurassic geohistories based on new thermal and burial models (GENEX® 4.0.3 software), constrained by new vitrinite reflectance data from the Amezraï basin. The comparison of the new subsidence curves from the studied areas with published subsidence curves from the Moroccan Atlas, the Saharan Atlas (Algeria) and Tunisian Atlas show that fast subsidence peaks were diachronous along the strike, being younger towards the east from Early–Middle Jurassic to Late Cretaceous. This analysis also evidences a close relationship between these high subsidence rate episodes and salt diapirism.
      PubDate: 2016-12-23T06:57:06.372065-05:
      DOI: 10.1111/bre.12223
  • Morphostructure, tectono-sedimentary evolution and seismic potential of
           the Horseshoe Fault, SW Iberian Margin
    • Authors: Sara Martínez-Loriente; Eulàlia Gràcia, Rafael Bartolome, Hector Perea, Dirk Klaeschen, Juan José Dañobeitia, Nevio Zitellini, Russell B. Wynn, Douglas G. Masson
      Abstract: High-resolution acoustic and seismic data acquired 100 km offshore Cape São Vicente, image with unprecedented detail one of the largest active reverse faults of the SW Iberian Margin, the Horseshoe Fault (HF). The HF region is an area seismogenically active, source of the largest magnitude instrumental and historical earthquake (Mw > 6) occurred in the SW Iberian Margin. The HF corresponds to a N40 trending, 110 km long, and NW-verging active thrust that affects the whole sedimentary sequence and reaches up to the seafloor, generating a relief of more than 1 km. The along-strike structural variability as well as fault trend suggests that the HF is composed by three main sub-segments: North (N25), Central (N50) and South (N45). Swath-bathymetry, TOBI sidescan sonar backscatter and parametric echosounder TOPAS profiles reveal the surface morphology of the HF block, characterized by several, steep (20°) small scarps located on the hangingwall, and a succession of mass transport deposits (i.e. turbidites) on its footwall, located in the Horseshoe Abyssal Plain. A succession of pre-stack depth-migrated multichannel seismic reflection profiles across the HF and neighbouring areas allowed us to constrain their seismo-stratigraphy, structural geometry, tectono-sedimentary evolution from Upper Jurassic to present-day, and to calculate their fault parameters. Finally, on the basis of segment length, surface fault area and seismogenic depth we evaluated the seismic potential of the HF, which in the worst-case scenario may generate an earthquake of magnitude Mw 7.8 ± 0.1. Thus, considering the tectonic behaviour and near-shore location, the HF should be recognized in seismic and tsunami hazard assessment models of Western Europe and North Africa.
      PubDate: 2016-12-09T07:39:45.216485-05:
      DOI: 10.1111/bre.12225
  • Impact of volcanism on the sedimentary record of the Neuquén rift basin,
           Argentina: towards a cause and effect model
    • Authors: Leandro D'Elia; Joan Martí, Martín Muravchik, Andrés Bilmes, Juan R. Franzese
      Abstract: The analysis of volcano-sedimentary infill in sedimentary basins constitutes a challenge for basin analysis and hydrocarbon exploration worldwide. In order to understand the contribution of volcanism to the sedimentary record in rift basins, we study the Jurassic effusive-explosive volcanic infill of an inverted extensional depocentre at the Neuquén Basin, Argentina. A cause and effect model that evaluates the relationship between volcanism and sedimentation was devised to develop a conceptual model for the tectono-stratigraphic evolution of this volcanic rift basin. We show how the variations in the volcanism, coupled with the activity of extensional faults, determined the types of volcanic edifices (i.e., composite volcanoes, graben-calderas, and lava fields). Volcanic edifices controlled the stacking patterns of the volcanic units as well as sedimentary systems. The landform of the volcanic edifices, as well as the styles and scales of the eruptions governed the sedimentary input to the basin, setting the main variables of the sedimentary systems, such as provenance, grain size, transport and deposition and geometry. As a result, the contrasting volcaniclastic input, from higher volcaniclastic input to lower volcaniclastic input, associated with different subsidence patterns, determined the high-resolution syn-rift infill patterns of the extensional depocentre. The cause and effect model presented in this study isolates the variables of the volcanic environments that control the sedimentary scenarios. We suggest that, by adjusting the first order input parameters of the model, these cause and effect scenarios could be adapted to similar rift basins, in order to establish predictive facies models with stratigraphic controls, and the impact of volcanism on their stratigraphic records.
      PubDate: 2016-11-27T23:01:13.332254-05:
      DOI: 10.1111/bre.12222
  • Analogue modelling of inverted domino-style basement fault systems
    • Authors: Lydia J. Jagger; Ken R. McClay
      Abstract: Inversion of pre-existing extensional fault systems is common in rift systems, back-arc basins and passive margins. It can significantly influence the development of structural traps in hydrocarbon basins. The analogue models of domino-style basement fault systems shown in this paper produced, on extension, characteristic hangingwall growth stratal wedges that, when contracted and inverted, formed classic inversion harpoon geometries and asymmetric hangingwall contractional fault-propagation folds. Segmented footwall shortcut faults formed as the basement faults were progressively back-rotated and steepened. The pre-existing extensional fault architectures, basement fault geometries and the relative hangingwall and footwall block rotations exerted fundamental controls on the inversion styles. Digital image correlation (DIC) strain monitoring illustrated complex vertical fault segmentation and linkage during inversion as the major faults were reactivated and strain was progressively transferred onto footwall shortcut faults. Hangingwall deformation during inversion was dominated by significant back-rotation as the inversion progressed. The mechanical stratigraphy of the cover sequences strongly influenced the fold and fault evolution of the reactivated fault systems. The implications of the experimental results for the interpretation and analysis of inversion structures are discussed and are compared with natural examples of inverted basement-involved extensional faults observed in seismic datasets.
      PubDate: 2016-11-06T23:15:52.203715-05:
      DOI: 10.1111/bre.12224
  • Impact of normal faulting and pre-rift salt tectonics on the structural
           style of salt-influenced rifts: the Late Jurassic Norwegian Central
           Graben, North Sea
    • Authors: Zhiyuan Ge; Rob L. Gawthorpe, Atle Rotevatn, Michel Bøgh Thomas
      Abstract: Studies of salt-influenced rift basins have focused on individual or basin-scale fault system and/or salt-related structure. In contrast, the large-scale rift structure, namely rift segments and rift accommodation zones and the role of pre-rift tectonics in controlling structural style and syn-rift basin evolution have received less attention. The Norwegian Central Graben, comprises a complex network of sub-salt normal faults and pre-rift salt-related structures that together influenced the structural style and evolution of the Late Jurassic rift. Beneath the halite-rich, Permian Zechstein Supergroup, the rift can be divided into two major rift segments, each comprising rift margin and rift axis domains, separated by a rift-wide accommodation zone – the Steinbit Accommodation Zone. Sub-salt normal faults in the rift segments are generally larger, in terms of fault throw, length and spacing, than those in the accommodation zone. The pre-rift structure varies laterally from sheet-like units, with limited salt tectonics, through domains characterised by isolated salt diapirs, to a network of elongate salt walls with intervening minibasins. Analysis of the interactions between the sub-salt normal fault network and the pre-rift salt-related structures reveals six types of syn-rift depocentres. Increasing the throw and spacing of sub-salt normal faults from rift segment to rift accommodation zone generally leads to simpler half-graben geometries and an increase in the size and thickness of syn-rift depocentres. In contrast, more complex pre-rift salt tectonics increases the mechanical heterogeneity of the pre-rift, leading to increased complexity of structural style. Along the rift margin, syn-rift depocentres occur as interpods above salt walls and are generally unrelated to the relatively minor sub-salt normal faults in this structural domain. Along the rift axis, deformation associated with large sub-salt normal faults created coupled and decoupled supra-salt faults. Tilting of the hanging wall associated with growth of the large normal faults along the rift axis also promoted a thin-skinned, gravity-driven deformation leading to a range of extensional and compressional structures affecting the syn-rift interval. The Steinbit Accommodation Zone contains rift-related structural styles that encompass elements seen along both the rift margin and axis. The wide variability in structural style and evolution of syn-rift depocentres recognised in this study has implications for the geomorphological evolution of rifts, sediment routing systems and stratigraphic evolution in rifts that contain pre-rift salt units.
      PubDate: 2016-10-20T04:26:35.141993-05:
      DOI: 10.1111/bre.12219
  • Chronology of Chilean Frontal Cordillera building from geochronological,
           stratigraphic and geomorphological data insights from Miocene
           intramontane-basin deposits
    • Authors: Katia Rossel; Germán Aguilar, Esteban Salazar, Joseph Martinod, Sébastien Carretier, Luisa Pinto, Albert Cabré
      Abstract: The Chilean Frontal Cordillera, near 28°45′S, provides a remarkable example to explore the evolution of the Central Andes; this area provides conspicuous pediment surfaces and continental deposits, which allowed us to analyse the timing and propagation of deformation which controlled the Andes building during the Cenozoic using structural, geomorphological, sedimentological, stratigraphic and geochronological data. The study area is characterized by outcrops of the Cerro del Burro Gravels, a continental deposit which is surrounded by four morphostructural mountain systems. Based on a 46 Ma tuff affected by a syncline, which is sealed by a 44 Ma tuff, we recognized an Eocene fault activity that contributed to the uplift of the western and northern systems, which have remained inactive during the last 44 Ma. The deformed lithologies during the last pulse of activity of the western fault and the youngest lithology carved by pediment processes (21 Ma) indicate a pediment surface developed during the Late Eocene and Oligocene. This pediment extended below the Cerro del Burro Gravels associated to a base level which drained to the east. We also recognized Miocene fault activity that played a main role in the uplift of the eastern and southern systems. Geochronological, stratigraphic and geomorphological data suggest a first pulse of fault activity between 19 and 13 Ma, which interrupted the pedimentation processes, developed an intramontane depocenter, and forced the accumulation of the Laguna Grande Succession in an alluvial-braided fluvial environment. After 13 Ma, an erosive event evidenced by the incision of valleys, resulted after the change in the extension and configuration of the hydric network.
      PubDate: 2016-10-11T07:20:58.109953-05:
      DOI: 10.1111/bre.12221
  • Cenozoic tectonic subsidence in the Qiongdongnan Basin, northern South
           China Sea
    • Authors: Zhongxian Zhao; Zhen Sun, Longtao Sun, Zhenfeng Wang, Zhipeng Sun
      Abstract: A number of major controversies exist in the South China Sea, including the timing and pattern of seafloor spreading, the anomalous alternating strike-slip movement on the Red River Fault, the existence of anomalous post-rift subsidence and how major submarine canyons have developed. The Qiongdongnan Basin is located in the intersection of the northern South China Sea margin and the strike-slip Red River fault zone. Analysing the subsidence of the Qiongdongnan Basin is critical in understanding these controversies. The basin-wide unloaded tectonic subsidence is computed through 1D backstripping constrained by the reconstruction of palaeo-water depths and the interpretation of dense seismic profiles and wells. Results show that discrete subsidence sags began to form in the central depression during the middle and late Eocene (45–31.5 Ma). Subsequently in the Oligocene (31.5–23 Ma), more faults with intense activity formed, leading to rapid extension with high subsidence (40–90 m Myr−1). This extension is also inferred to be affected by the sinistral movement of the offshore Red River Fault as new subsidence sags progressively formed adjacent to this structure. Evidence from faults, subsidence, magmatic intrusions and strata erosion suggests that the breakup unconformity formed at ca. 23 Ma, coeval with the initial seafloor spreading in the southwestern subbasin of the South China Sea, demonstrating that the breakup unconformity in the Qiongdongnan Basin is younger than that observed in the Pearl River Mouth Basin (ca. 32–28 Ma) and Taiwan region (ca. 39–33 Ma), which implies that the seafloor spreading in the South China Sea began diachronously from east to west. The post-rift subsidence was extremely slow during the early and middle Miocene (16 m Myr−1, 23–11.6 Ma), probably caused by the transient dynamic support induced by mantle convection during seafloor spreading. Subsequently, rapid post-rift subsidence occurred during the late Miocene (144 m Myr−1, 11.6–5.5 Ma) possibly as the dynamic support disappeared. The post-rift subsidence slowed again from the Pliocene to the Quaternary (24 m Myr−1, 5.5–0 Ma), but a subsidence centre formed in the west with the maximum subsidence of ca. 450 m, which coincided with a basin with the sediment thickness exceeding 5500 m and is inferred to be caused by sediment-induced ductile crust flow. Anomalous post-rift subsidence in the Qiongdongnan Basin increased from ca. 300 m in the northwest to ca. 1200 m in the southeast, and the post-rift vertical movement of the basement was probably the most important factor to facilitate the development of the central submarine canyon.
      PubDate: 2016-09-29T00:16:55.903215-05:
      DOI: 10.1111/bre.12220
  • Oligocene-Miocene Great Lakes in the India-Asia Collision Zone
    • Authors: Peter G. DeCelles; Isla S. Castañeda, Barbara Carrapa, Juan Liu, Jay Quade, Ryan Leary, Liyun Zhang
      Abstract: The Himalayan-Tibetan Plateau is Earth's highest topographic feature, and formed largely during Cenozoic time as India collided with and subducted beneath southern Asia. The>1300 km long, late Oligocene-early Miocene Kailas basin formed within the collisional suture zone more than 35 Ma after the onset of collision, and provides a detailed picture of surface environments, processes and possible geodynamic mechanisms operating within the suture zone during the ongoing convergence of India and Asia. We present new geochronological, sedimentological, organic geochemical and palaeontological data from a previously undocumented 400 km long portion of the Kailas basin. The new data demonstrate that this part of the basin was partly occupied by large, deep, probably meromictic lakes surrounded by coal-forming swamps. Lacustrine facies include coarse- and fine-grained turbidites, profundal black shales and marginal Gilbert-type deltas. Organic geochemical temperature proxies suggest that palaeolake water was warmer than 25 °C, and cyprinid fish fossils indicate an ecology capable of supporting large fish. Our findings demonstrate a brief period of low elevation in the suture zone during Oligocene-Miocene time (26–21 Ma) and call for a geodynamic mechanism capable of producing a long (>1000 km) and narrow basin along the southern edge of the upper, Asian plate, long after the onset of intercontinental collision. Kailas basin deposits presently are exposed at elevations>6000 m, requiring dramatic elevation gain in the region after Kailas deposition, without strongly shortening the upper crust. Episodic Indian slab rollback, followed by break-off and subsequent renewal of flat-slab subduction, can account for features of the Kailas basin.
      PubDate: 2016-09-26T23:16:56.572264-05:
      DOI: 10.1111/bre.12217
  • Normal fault evolution and coupled landscape response: examples from the
           Southern Apennines, Italy
    • Authors: Duna C. Roda-Boluda; Alexander C. Whittaker
      Abstract: We present new data addressing the evolution, activity and geomorphic impact of three normal faults in the Southern Apennines: the Vallo di Diano, East Agri and Monti della Maddalena faults. We show that these faults have minimum total throws of ca. 1000–2000 m, and throw rates of ca. 0.7–1 mm year−1 for at least the last ca. 18 ka. We demonstrate that for the Vallo di Diano and East Agri faults, the landscape is effectively recording tectonics, with relief, channel and catchment slopes varying along fault strike in the same manner as normal fault activity does, with little apparent influence of lithology. We therefore use these data to reconstruct the time-integrated history of fault interaction and growth. From the distribution of knickpoints on the footwall channels, we infer two episodes of base level change, which we attribute to fault interaction episodes. We reconstruct the amount of throw accumulated after each of these events, and the segments involved in each, from the fault throw profiles, and use fault interaction theory to estimate the magnitude of the perturbations and past throw rates. We estimate that fault linkage events took place 0.7 ± 0.2 Ma and 1.4 ± 0.3 Ma in the Vallo di Diano fault, and 1 ± 0.1 in the East Agri Fault, and that both faults likely started their activity between 3 and 3.5 Ma. These fault linkage scenarios are consistent with the observed knickpoint heights. This method for reconstructing fault evolution could potentially be applied for any normal faults for which there is information about throw and throw rates, and in which channels are transiently responding to tectonics.
      PubDate: 2016-09-24T00:05:47.201573-05:
      DOI: 10.1111/bre.12215
  • Why is there no Coastal Cordillera at the Arica Bend (Western Central
    • Authors: Andrea Madella; Romain Delunel, Laurence Audin, Fritz Schlunegger
      Abstract: The architecture of the Western Andes is remarkably constant between southern Peru and northern Chile. An exception, however, is present near Arica at 18°S, where the Andes change their strike direction by ca. 50° and the Coastal Cordillera is absent over an along-strike width of 50 km. Although this feature has been mentioned in several previous studies, no effort has been made yet to describe and explain this peculiar morphology of the Western Central Andean forearc. Here, we propose a large-scale model to explain the Myr-long low uplift rate of the Arica Bend concerning seismic coupling and continental wedge-top basin evolution. New geomorphic and sedimentologic data are integrated with seismicity and structural data from the literature to interpret the post-Oligocene pattern of uplift, erosion and sediment transport to the trench. Results show that the Arica Bend has been marked by exceptionally low coastal uplift rates over post-Oligocene timescales. In addition, this uplift anomaly at the Arica Bend correlates with relatively high sediment discharge to the corresponding trench segment since late Oligocene time. We interpret that before 25 Ma, the forming seaward concavity of the subduction zone induced trench-parallel extension at the curvature apex of the overriding forearc. The subsequent low uplift rate would have then triggered a feedback mechanism, where the interplay between relatively low interplate friction, low coastal uplift and relatively high sediment discharge favoured Myr-long relative subsidence at the Arica Bend, in contrast to Myr-long uplift of the Coastal Cordillera north and south of it.
      PubDate: 2016-09-15T06:42:01.468138-05:
      DOI: 10.1111/bre.12218
  • A reconstruction of the North Atlantic since the earliest Jurassic
    • Authors: Nicholas Barnett-Moore; Dietmar R. Müller, Simon Williams, Jakob Skogseid, Maria Seton
      Abstract: The stretched continental margins of the North Atlantic region record a plate kinematic history dominated by major episodes of extension since the Late Palaeozoic. Accounting for the restoration of this stretched continental crust across the region, and the subsequent derivation of plausible full-fit configurations between these continents, prior to extension, still remains unresolved. Previous plate reconstructions have highlighted difficulties such as determining the amount of extension to be distributed across the multiple episodes of rifting, or defining the distribution of extension across intraplate deformation occurring adjacent to the rifting of two major continents. Here, we implement a new approach to derive a set of total reconstruction poles based on a full-fit, palinspastic restoration of the conjugate margins that considers the rifting evolution of the North Atlantic in a regional plate kinematic context since the Earliest Jurassic. Gravity inversion forms the basis of our regional crustal thickness estimates, and aids in the identification of thinned continental crust. Our crustal restoration estimates are computed in multiple phases along margin segments in accordance with the timing of their major rifting episodes. Our model predicts a full-fit, prerift, palaeogeographic position of all the major continents across the North Atlantic; and predicts a time-dependent evolution of multiple phases of extension including regional divergence directions, consistent with previous observations. Our plate model represents a new approach to plate kinematic reconstructions incorporating the application of a multiphase restoration methodology applied in a major regional context, constrained by the synthesis of several different geological and geophysical data sets.
      PubDate: 2016-09-14T23:51:22.660094-05:
      DOI: 10.1111/bre.12214
  • Constraining basin thermal history and petroleum generation using
           palaeoclimate data in the Piceance Basin, Colorado
    • Authors: Yao Tong; Daniel E. Ibarra, Jeremy K. Caves, Tapan Mukerji, Stephan A. Graham
      Abstract: Careful assessment of basin thermal history is critical to modelling petroleum generation in sedimentary basins. In this paper, we propose a novel approach to constraining basin thermal history using palaeoclimate temperature reconstructions and study its impact on estimating source rock maturation and hydrocarbon generation in a terrestrial sedimentary basin. We compile mean annual temperature (MAT) estimates from macroflora assemblage data to capture past surface temperature variation for the Piceance Basin, a high-elevation, intermontane, sedimentary basin in Colorado, USA. We use macroflora assemblage data to constrain the temporal evolution of the upper thermal boundary condition and to capture the temperature change with basin uplift. We compare these results with the case where the upper thermal boundary condition is based solely upon a simplified latitudinal temperature estimate with no elevation effect. For illustrative purposes, 2 one-dimensional (1-D) basin models are constructed using these two different upper thermal boundary condition scenarios and additional geological and geochemical input data in order to investigate the impact of the upper thermal boundary condition on petroleum source rock maturation and kerogen transformation processes. The basin model predictions indicate that the source rock maturation is very sensitive to the upper thermal boundary condition for terrestrial basins with variable elevation histories. The models show substantial differences in source rock maturation histories and kerogen transformation ratio over geologic time. Vitrinite reflectance decreases by 0.21%Ro, source rock transformation ratio decreases 10.5% and hydrocarbon mass generation decreases by 16% using the macroflora assemblage data. In addition, we find that by using the macroflora assemblage data, the modelled depth profiles of vitrinite reflectance better matches present-day measurements. These differences demonstrate the importance of constraining thermal boundary conditions, which can be addressed by palaeotemperature reconstructions from palaeoclimate and palaeo-elevation data for many terrestrial basins. Although the palaeotemperature reconstruction compiled for this study is region specific, the approach presented here is generally applicable for other terrestrial basin settings, particularly basins which have undergone substantial subaerial elevation change over time.
      PubDate: 2016-09-14T23:50:58.907287-05:
      DOI: 10.1111/bre.12213
  • Synsedimentary broken-foreland tectonics during the Paleogene in the Andes
           of NW Argentine: new evidence from regional to centimetre-scale
           deformation features
    • Authors: Carolina Montero-López; Cecilia del Papa, Fernando Hongn, Manfred R. Strecker, Alejandro Aramayo
      Abstract: Unravelling the spatiotemporal evolution of the Cenozoic Andean (Altiplano-Puna) plateau has been one of the most intriguing problems of South American geology. Despite a number of investigations, the early deformation and uplift history of this area remained largely enigmatic. This paper analyses the Paleogene tectono-sedimentary history of the Casa Grande Basin, in the present-day transition zone between the northern sector of the Puna Plateau and the northern part of the Argentine Eastern Cordillera. Our detailed mapping of synsedimentary structures records the onset of regional contractional deformation during the middle Eocene, revealing reactivation of Cretaceous extensional structures and the development of doubly vergent thrusts. This is in agreement with records from other southern parts of the Puna Plateau and the Eastern Cordillera. These observations indicate the existence of an Eocene broken foreland setting within the region, characterized by low-lying compressional basins and ranges with spatially disparate sectors of deformation, which was subsequently subjected to regional uplift resulting in the attainment of present-day elevations during the Neogene.
      PubDate: 2016-09-07T23:35:57.567293-05:
      DOI: 10.1111/bre.12212
  • Interpretation of a gas chimney in the Polish Carpathian Foredeep based on
           integrated seismic and geochemical data
    • Authors: Paweł Marzec; Henryk Sechman, Monika Kasperska, Kamil Cichostępski, Piotr Guzy, Kaja Pietsch, Szczepan J. Porębski
      Abstract: Gas chimneys are common in offshore petroliferous basins, but little known on land where seismic columnar anomalies are often attributed as poor data quality or processing artefacts. This study utilizes high-quality 3D seismic data to document a seismic columnar anomaly penetrating through the Miocene heterolithic submarine fan-deltaic infill of the Carpathian Foredeep. The interpreted gas chimney exhibits vertically clustered velocity push-down features throughout the attenuated amplitude column accompanied by gas shows in well tests, has its root in gas-bearing Palaeozoic interval and culminates in an anomalous geochemical gas record at soil level. The chimney system, ca 2 km in height and 500-m wide, begins above the flank of a rotational bedrock fault-block and extends vertically along a fault-controlled conduit. At shallower levels, it passes upwards into amplitude wipeout zones that spread laterally around and partly across thin, gas-charged reservoirs showing bright spots associated with an AVO response. At shallow levels, gas pathways through muddy slope and deltaic clinoforms are not imaged in low-fold regions of the seismic volume. The surface geochemical anomalies, in contrast to the microbial methane signature of the Miocene succession, show significant enrichment in higher alkanes and alkenes with C2H6/C3H8 ratios indicative of a deep-sourced, thermogenic gas or gas condensate. These anomalies form a semi-enclosed halo around the chimney. Despite the juxtaposition of biogenic and thermogenic methane, the chimney structure imaged on seismic data supports a causal link of gases derived from Palaeozoic source rocks ascending to the surface.
      PubDate: 2016-09-05T23:36:07.199135-05:
      DOI: 10.1111/bre.12216
  • Spatial variations of magmatic crustal accretion during the opening of the
           Tyrrhenian back-arc from wide-angle seismic velocity models and seismic
           reflection images
    • Authors: Manel Prada; Valenti Sallares, César R. Ranero, Montserrat G. Vendrell, Ingo Grevemeyer, Nevio Zitellini, Roberto Franco
      Abstract: The structural complexity of back-arc basins is related to the evolution of the associated subduction system. Here, we present an integrated geophysical and geological study that constrains the 3D spatial variability of magmatic activity along the Tyrrhenian back-arc basin. We use wide-angle seismic and gravity data, acquired in 2010 within the MEDOC experiment along a ~300 km-long NW-SE transect that extends from SE Sardinia Island to the NW Sicily continental margin, across the Cornaglia Terrace. The geophysical transect is coincident with a seismic reflection line from the Italian CROP experiment that we have re-processed. The geophysical results, together with available basement dredges, support a basement along the profile fundamentally composed of continental-type rocks, locally affected by subduction-related magmatism. The continental nature of this region contrasts with the nature of the basement inferred along two geophysical cross-sections located to the north of the Cornaglia Terrace in which seismic velocity of the lower crust supports significant magmatic crustal accretion. The comparison of these three cross-sections supports that the highest magmatic activity occurred in the central and most extended region of the basin, whereas it was less important in the North and practically nonexistent in the South. These observations indicate abrupt variations of magmatism during the basin formation. As in other back-arcs, the temperature, water content and composition of the mantle might have played an important role in such variation, but they fail to explain the abruptness of it. We propose that the interaction of the overriding continental lithospheres of Adria and Africa with the Apenninic-Calabrian subduction system caused changes in slab rollback and trench retreat dynamics, which in turn resulted in variations of back-arc stretching and magmatism. Based on our observations, we suggest that the Cornaglia Terrace formation process might share some similarities with the formation of oceanic crust in the Red Sea.
      PubDate: 2016-08-17T23:15:52.049392-05:
      DOI: 10.1111/bre.12211
  • 3D numerical modelling of marine organic matter distribution: example of
           the early Jurassic sequences of the Lusitanian Basin (Portugal)
    • Authors: Benjamin Bruneau; Benoit Chauveau, Luis Vitor Duarte, Guy Desaubliaux, Isabelle Moretti, François Baudin
      Abstract: Due to the multiple controlling factors involved, it is a challenging task to identify and quantify the processes influencing the distribution and heterogeneity of marine organic-rich rocks. To improve our understanding of these deposits, we model their burial history and stratigraphic evolution as well as processes linked to marine organic matter history throughout the Lower Jurassic in of the Northern Lusitanian Basin (Western Iberian Margin). This 15-Ma-long interval is modelled using 100-kyr time steps to simulate lithologies and organic matter heterogeneity as layers with a thickness of 2–5 m, depending on the sedimentation rate in the basin. The model is calibrated by well and outcrop data which provide structural and biostratigraphic constraints, as well as information on the depositional facies and geochemistry of the sediments. The results show that the presence of organic-rich intervals is linked to first-order variations in the basin geometry and sedimentation rates. Without considering any variation of primary productivity or oxygen content in surface sea waters, the parameters of basin geometry and sedimentation rate are sufficient to predict the main characteristics of source rocks, i.e. their occurrence, thickness and mineralogy at the basin scale. However, to fit the measured organic carbon contents, we need to take account of other parameters such as variations of primary productivity or changes in dissolved oxygen concentration.
      PubDate: 2016-08-17T23:15:40.448212-05:
      DOI: 10.1111/bre.12210
  • Mass-transport complexes as markers of deep-water fold-and-thrust belt
           evolution: insights from the southern Magdalena fan, offshore Colombia
    • Authors: Andrea Ortiz-Karpf; David M. Hodgson, Christopher A.-L. Jackson, William D. McCaffrey
      Abstract: Mass wasting is an important process in the degradation of deep-water fold-and-thrust belts. However, the relationship between mass-transport complex (MTC) emplacement and the timing and spatial progression of contractional deformation of the seabed have not been extensively studied. This study uses high-quality, 3D seismic reflection data from the southern Magdalena Fan, offshore Colombia to investigate how the growth of a deep-water fold-and-thrust belt (the southern Sinú fold belt) is recorded in the source, distribution and size of MTCs. More than nine distinct, but coalesced MTCs overlie a major composite basal erosion surface. This surface formed by multiple syn- and post-tectonic mass-wasting events and is thus highly diachronous, thereby recording a protracted period of tectonism, seascape degradation and associated sedimentation. The size and source location of these MTCs changed through time: the oldest ‘detached’ MTCs are relatively small (over 9–100 km2 in area) and sourced from the flanks of growing anticlines, whereas the younger ‘shelf-attached’ MTCs are considerably larger (more than 200–300 km2), are sourced from the shelf, and post-date the main phase of active folding and thrusting. Changes in the source, distribution and size of MTCs are tied to the sequential nucleation, amplification and along-strike propagation of individual structures, showing that MTCs can be used to constrain the timing and style of contractional deformation, and seascape evolution in time and space.
      PubDate: 2016-08-02T03:42:10.696231-05:
      DOI: 10.1111/bre.12208
  • Reverse migration of lithofacies boundaries and shoreline in response to
           sea-level rise
    • Authors: Carolina Baumanis; Wonsuck Kim
      Abstract: The migration of the lithofacies boundaries preserved in the sedimentary record is key to interpreting changes in depositional environments. Grain size is one of the most recognizable physical characteristics of lithofacies. The advance and retreat of grain-size breaks, as a proxy for lithofacies boundaries (e.g. gravel–sand transition), is commonly attributed to variations in external controls (e.g. climate, sea level and tectonic subsidence). While most models of fluviodeltaic systems focus on predicting the response of the shoreline to these forcings, none have thoroughly incorporated the migration of grain-size transitions (GST) that coevolve with the shoreline. We present a numerical delta evolution model that treats both the shoreline and GST as moving boundaries to provide quantitative understanding of the dynamic interaction between the downstream boundary (shoreline) and the upstream lithofacies boundaries (GSTs) of the fluviodeltaic system under relative sea-level rise. We tested a range of relative sea-level rise rates in the model. The shoreline and GST gradually reduced their progradation rates and eventually retreated landward as the fluviodeltaic topset and foreset elongated. However, their timings of retreat were different, resulting in a counterintuitive case for a quicker retreat of GST while the shoreline still continued to advance. A series of scaled flume experiments with a sand and crushed walnut sediment mixture captured the same behaviours of these two moving boundaries. We found that GST experienced higher relative sea-level rise (RSLR) rates than the shoreline. This additional RSLR rate scales with the downstream river slope and the shoreline progradation rate to cause earlier GST retreat in comparison to the shoreline. The fundamental understanding from this study of migration of both the GST and shoreline in fluviodeltaic systems will aid in accurately assessing the trajectories of GST in sedimentary strata as a proxy for environmental change.
      PubDate: 2016-07-22T23:40:43.359229-05:
      DOI: 10.1111/bre.12209
  • Comment on Non-unique stratal geometries: implications for sequence
           stratigraphic interpretations, by: P.M. Burgess and G.D. Prince, Basin
           Research (2015) 27, 351–365
    • Authors: Octavian Catuneanu; Massimo Zecchin
      Abstract: The non-unique variability highlighted by Burgess & Prince (Basin Res. 2015, 27, 351) (i.e. the origin and timing of maximum flooding surfaces, maximum regressive surfaces and subaerial unconformities; the process of topset aggradation in relation with the various types of shoreline trajectory; and the multiple controls that may affect the progradation and retrogradation of a shoreline) is irrelevant to the workflow of sequence stratigraphy. What is relevant is the observation of the unique stratal geometries that are diagnostic to the definition of all units and surfaces of sequence stratigraphy. In downstream-controlled settings, these unique stratal stacking patterns relate to the forced regressive, normal regressive and transgressive shoreline trajectories. Multiple controls interplay during the formation of each type of stacking pattern, including accommodation, sediment supply and the energy of the sediment-transport agents. This interplay explains the non-unique variability, but does not change the unique criteria that afford a consistent application of sequence stratigraphy. Failure to rationalize the non-unique variability within the context of unique stratal geometries is counterproductive, and obscures the simple workflow of sequence stratigraphy.
      PubDate: 2016-07-13T23:10:26.315159-05:
      DOI: 10.1111/bre.12192
  • Reply to Comment of O. Catuneanu and M. Zecchin on Non-unique stratal
           geometries: implications for sequence stratigraphic interpretations, by:
           P. M. Burgess and G. D. Prince, Basin Research (2015) 27, 351–365
    • Authors: P. M. Burgess; G. D. Prince
      PubDate: 2016-07-09T00:00:40.483207-05:
      DOI: 10.1111/bre.12206
  • Slope-to-basin stratigraphic evolution of the northwestern Great Bahama
           Bank (Bahamas) during the Neogene to Quaternary: interactions between
           downslope and bottom currents deposits
    • Authors: Mélanie Principaud; Jean-Pierre Ponte, Thierry Mulder, Hervé Gillet, Cécile Robin, Jean Borgomano
      Abstract: Multichannel high-resolution seismic data along the northwestern margin of the Great Bahama Bank (GBB), Bahamas, detail the internal geometry and depositional history of a Neogene-Quaternary carbonate slope-to-basin area. The stratigraphic architecture through this period evolves from (i) a mud-dominated slope apron during the Miocene, (ii) a debris-dominated base-of-slope apron during the Late Pliocene and then (iii) return to a slope apron with very short prograding clinoformal aprons during the Pleistocene. This geometric evolution was broadly constrained by the development of the Santaren Drift by bottom current since the Langhian. The drift expands along the northwestern GBB slope, forming a continuous correlative massive feature that shows successive phases of growth and retreat and influenced the downslope sediments distribution. Indeed, Late Pliocene deposits are confined into the moat, forming a strike-continuous coarse debrites belt along the mid-slope, preventing their free expansion into the basin. The occurrence of basinal drift that operated since 15 Ma showed a significant upslope growth around 3.6 Ma and is interpreted as resulting from the closure of the Central American Seaway which also coincides with a global oceanographic re-organization and climate changes in the Northern Hemisphere.
      PubDate: 2016-07-05T06:29:08.852657-05:
      DOI: 10.1111/bre.12195
  • Deciphering exhumation and burial history with multi-sample down-well
           thermochronometric inverse modelling
    • Authors: Richard A. Ketcham; Andrés Mora, Mauricio Parra
      Abstract: The ability of thermochronometric data to shed light on the geologic history of samples and localities through thermal history inverse modelling is enhanced by the degree to which additional geological information can be incorporated into the modelling process. In this contribution, we describe a new set of methods and processes implemented in the HeFTy modelling software for specifying the stratigraphic relationships between samples down a well or borehole, allowing them to be modelled simultaneously, and demonstrate their use in bringing better definition to both predepositional and burial histories. Data from two wells in the Colombian Andes are examined, one in the Middle Magdalena Valley that experienced not only fast Miocene burial but also features a Mio-Pliocene unconformity, and one in the eastern foothills of the Eastern Cordillera in which burial was accomplished by a combination of sedimentation and overthrusting. Multiple-sample modelling in both wells considerably refines the results that are obtained from single-sample modelling. We also demonstrate how to use these methods to pose and evaluate distinct hypotheses concerning the geologic history. As a general rule, it is best practice to set up thermal history inverse models to pose specific geological questions while ruling out geologically impossible or inconsistent solutions.
      PubDate: 2016-07-04T23:06:32.541647-05:
      DOI: 10.1111/bre.12207
  • Permian exhumation of the Montagne Noire core complex recorded in the
           Graissessac-Lodève Basin, France
    • Authors: Lily S. Pfeifer; Gerilyn S. Soreghan, Stéphane Pochat, Jean Van Den Driessche, Stuart N. Thomson
      Abstract: The paleogeographic reconstruction of the Variscan Mountains during late Carboniferous-Permian post-orogenic extension remains poorly understood, owing to the subsequent erosion and/or burial of most associated sedimentary basins during the Mesozoic. The Graissessac-Lodève Basin (southern France) preserves a thick and exceptionally complete record of continental sedimentation spanning late Carboniferous through late Permian time. This section records the localized tectonic and paleogeographic evolution of southern France in the context of the low-latitude Variscan Belt of Western Europe. This study presents new detrital zircon and framework mineralogy data that address the provenance of siliciclastic strata exposed in the basin. The ages and compositions of units that constitute the Montagne Noire metamorphic core complex (west of the basin) dictate the detrital zircon age populations and sandstone compositions in Permian strata, recording rapid exhumation and unroofing of the Montagne Noire dome. Cambrian-Archean zircons and metamorphic lithic-rich compositions record derivation from recycled detritus of the earliest Paleozoic sedimentary cover and Neoproterozoic-early Cambrian metasedimentary Schistes X, which formerly covered the Montagne Noire dome. Ordovician zircons and subarkosic framework compositions indicate erosion of orthogneiss units that formed a large part of the dome. The youngest zircon population (320–285 Ma) reflects derivation from late Carboniferous-early Permian granite units in the axial zone of the Montagne Noire. This population appears first in the early Permian, persists throughout the Permian section and is accompanied by sandstone compositions dominated by feldspar, polycrystalline quartz and metamorphic lithic fragments. The most recent migmatization, magmatism and deformation occurred ca. 298 ± 2 Ma, at ca. 17 km depth (based on peak metamorphic conditions). Accordingly, these new provenance data, together with zircon fission-track thermochronology, demonstrate that exhumation of the Montagne Noire core complex was rapid (1–17 mm year−1) and early (300–285 Ma), reflecting deep-seated uplift in the southern Massif Central during post-orogenic extension.
      PubDate: 2016-07-04T06:47:22.101332-05:
      DOI: 10.1111/bre.12197
  • Gravitational deformation and inherited structural control on slope
    • Authors: Juan Becerra; César Arriagada, Eduardo Contreras-Reyes, Sebastián Bascuñan, Gregory P. De Pascale, Christian Reichert, Juan Díaz-Naveas, Natalia Cornejo
      Abstract: Subduction zones provide direct insight into plate boundary deformation and by studying these areas we better understand tectonic processes and variability over time. We studied the structure of the offshore subduction zone system of the Pampean flat-slab segment (ca. 29–33°S) of the Chilean margin using seismic and bathymetric constraints. Here, we related and analysed the structural styles of the offshore and onshore western fore-arc. Overlying the acoustic top of the continental basement, two syn-extensional seismic sequences were recognised and correlated with onshore geological units and the Valparaíso Forearc Basin seismic sequences: (SII) Pliocene-Pleistocene and (SI) Miocene-Pliocene (Late Cretaceous (') to Miocene-Pliocene) syn-extensional sequences. These sequences are separated by an unconformity (i.e. Valparaíso Unconformity). Seismic reflection data reveal that the eastward dipping extensional system (EI) recognised at the upper slope can be extended to the middle slope and controlled the accumulation of the older seismic package (SI). The westward dipping extensional system (EII) is essentially restricted to the middle slope. Here, EII cuts the eastward dipping extensional system (EI), preferentially parallel to the inclination of the older sequences (SI), and controlled a series of middle slope basins which are filled by the Pliocene-Pleistocene seismic sequence (SII). At the upper slope and in the western Coastal Cordillera, the SII sequence is controlled by eastward dipping faults (EII) which are the local reactivation of older extensional faults (EI). The tectonic boundary between the middle (eastern outermost forearc block) and upper continental slope (western coastal block) is a prominent system of trenchward dipping normal fault scarps (ca. 1 km offset) that resemble a major trenchward dipping extensional fault system. This prominent structural feature can be readily detected along the Chilean erosive margin as well as the two extensional sets (EI and EII). Evidence of slumping, thrusting, reactivated faults and mass transport deposits, were recognised in the slope domain and locally restricted to some eastern dipping faults. These features could be related to gravitational effects or slope deformation due to coseismic deformation. The regional inclination of the pre-Pliocene sequences favoured the gravitational collapse of the outermost forearc block. We propose that the structural configuration of the study area is dominantly controlled by tectonic erosion as well as the uplift of the Coastal Cordillera, which is partially controlled by pre-Pliocene architecture.
      PubDate: 2016-06-20T03:41:03.16707-05:0
      DOI: 10.1111/bre.12205
  • Deciphering the origin of cyclical gravel front and shoreline progradation
           and retrogradation in the stratigraphic record
    • Authors: John J. Armitage; Peter M. Burgess, Gary J. Hampson, Philip A. Allen
      Abstract: Nearly all successions of the near-shore strata exhibit cyclical movements of the shoreline, which have commonly been attributed to cyclical oscillations in relative sea level (combining eustasy and subsidence) or, more rarely, to cyclical variations in sediment supply. It has become accepted that cyclical change in sediment delivery from source catchments may lead to cyclical movement of boundaries such as the gravel front, particularly in the proximal segments of sediment-routing systems. In order to quantitatively assess how variations in sediment transport as a consequence of change in relative sea-level and surface run-off control stratigraphic architecture, we develop a simple numerical model of sediment transport and explore the sensitivity of moving boundaries within the sediment-routing system to change in upstream (sediment flux, precipitation rate) and downstream (sea level) controls. We find that downstream controls impact the shoreline and sand front, while the upstream controls can impact the whole system depending on the amplitude of change in sediment flux and precipitation rate. The model implies that under certain conditions, the relative movement of the gravel front and shoreline is a diagnostic marker of whether the sediment-routing system experienced oscillations in sea level or climatic conditions. The model is then used to assess the controls on stratigraphic architecture in a well-documented palaeo-sediment-routing system in the Late Cretaceous Western Interior Seaway of North America. Model results suggest that significant movement of the gravel front is forced by pronounced (±50%) oscillations in precipitation rate. The absence of such movement in gravel front position in the studied strata implies that time-equivalent movement of the shoreline was driven by relative sea-level change. We suggest that tracking the relative trajectories of internal boundaries such as the gravel front and shoreline is a powerful tool in constraining the interpretation of stratigraphic sequences.
      PubDate: 2016-06-08T19:44:21.220956-05:
      DOI: 10.1111/bre.12203
  • Detrital zircons as palaeodrainage indicators: insights into southeastern
           Gondwana from Permian basins in eastern Australia
    • Authors: Uri Shaanan; Gideon Rosenbaum
      Abstract: Radioisotope geochronology of detrital grains coupled with quantitative classification of grain morphology can provide valuable insight into the history of sediment transportation and recycling. Here we present ca. 750 new concordant U-Pb ages from detrital zircon grains from a relatively understudied Permian sedimentary succession in the New England Orogen (eastern Australia), coupled with values of abrasion that provides a proxy for the relative source-to-sink distance. We show that cumulative proportion curves for age groups that correspond to plausible source regions provide insights into the palaeodrainage, even if the basin stratigraphy is relatively poorly constrained. This approach is particularly suitable for investigating complex depositional systems that received inflow from different provenance, such as back-arc and intra-cratonic basins. Using the example from eastern Australia, our results show that during the Early Permian, a large regional fluvial system transported detritus from continental Gondwana across the landscape of the former active continental margin (New England Orogen) and the simultaneously developing East Australian Rift System. In addition, a local drainage system mobilised detritus within the New England Orogen. Our new constraints for the Early Permian palaeogeography support the idea that the Lower Permian successions of the southern New England Orogen were deposited in a back-arc region that was likely linked to a retreating subduction zone.
      PubDate: 2016-06-02T23:06:09.558148-05:
      DOI: 10.1111/bre.12204
  • Generic 3D interpolation of Holocene base-level rise and provision of
           accommodation space, developed for the Netherlands coastal plain and
           infilled palaeovalleys
    • Authors: Kay Koster; Jan Stafleu, Kim M. Cohen
      Abstract: We present an interpolation model that describes Holocene groundwater level rise and the creation of accommodation space in 3D in the Rhine-Meuse delta – the Netherlands. The model area (ca. 12 400 km2) covers two palaeovalleys of Late Pleistocene age (each 30 km wide) and the overlying Holocene deposits of the Rhine-Meuse delta, the Holland coastal plain, and the Zuiderzee former lagoon. Water table rise is modelled from 10 800 to 1000 cal. BP, making use of age-depth relations based on 384 basal peat index points, and producing output in the form of stacked palaeo groundwater surfaces, groundwater age-depth curves, and voxel sets. These products allow to resolve (i) regional change and variations of inland water table slopes, (ii) spatial differences in the timing and pacing of transgression, and (iii) analysis of interplay of coastal, fluvial and subsidence controls on the provision of accommodation space. The interpolation model is a multi-parameter trend function, to which a 3D-kriging procedure of the residuals is added. This split design deploys a generic approach for modelling provision of accommodation space in deltas and coastal lowlands, aiming to work both in areas of intermediate data availability and in the most data-rich environments. Major provision of accommodation space occurred from 8500 cal BP onwards, but a different evolution occurred in each of the two palaeovalleys. In the northern valley, creation of accommodation space began to stall at 7500 cal BP, while in the southern valley provision of new accommodation space in considerable quantities continued longer. The latter is due to the floodplain gradient that was maintained by the Rhine, which distinguishes the fluvial deltaic environment from the rest of the back-barrier coastal plain. The interpolation results allow advanced mapping and investigation of apparent spatial differences in Holocene aggradation in larger coastal sedimentary systems. Furthermore, they provide a means to generate first-order age information with centennial precision for 3D geological subsurface models of Holocene deltas and valley fills. As such, the interpolation is of use in studies into past and present land subsidence and into low land sedimentation.
      PubDate: 2016-05-24T23:35:45.541792-05:
      DOI: 10.1111/bre.12202
  • Palaeovalleys in foreland ramp settings: what happens as accommodation
           decreases down dip'
    • Authors: Rhodri M. Jerrett; Stephen S. Flint, Rufus L. Brunt
      Abstract: Recent advances in our understanding of palaeovalleys are largely guided by examples from passive margins, in which accommodation increases down depositional dip. This study tests these models against a dataset from the Pennsylvanian Breathitt Group of the central Appalachian foreland basin, USA. This fluvio-deltaic succession contains extensive erosionally based fluvio-estuarine sand bodies that can be tracked over 80 km down depositional dip from a proximal zone of high accommodation close to the orogenic margin to a distal, lower accommodation zone close to the cratonic margin of the basin. The sand bodies are up to 25 m thick, multi-storey and characterized in their lower parts by strongly amalgamated storeys containing sandy fluvial to estuarine bar accretion elements, and in their middle to upper parts by more fully preserved storeys up to 10 m thick and laterally extensive over 100s of metres. The upper storeys include abandonment channel-fills of heterolithic marine or marginal marine deposits or muddy to sandy point-bar elements. Three major regional-scale architectures include: (i) Tabular sand bodies that everywhere incise open marine prodelta and mouth bar facies and are interpreted as palaeovalleys formed during falling stage and lowstand systems tracts, when eustatic sea-level fall outpaced tectonic subsidence across the entire study area. (ii) Sand bodies that incise genetically related floodplain lake and/or bay-fill minor mouth bar deposits up depositional dip and open marine prodelta and mouth bar facies down dip. These stacked distributary channel deposits map down dip into palaeovalleys and formed when up dip subsidence rate resulted in positive, but reduced rate of accommodation creation, while lower tectonic subsidence rate down-dip resulted in incision. (iii) Sand bodies that incise genetically related floodplain, lake and/or bay-fill minor mouth bars up dip and pass down-dip into genetically related unconfined floodplain, prodelta and mouth bar deposits. These sand bodies represent stacked distributary channel fills and channel amalgamation was the product of high rates of lateral migration, typical of the behaviour of channels above their backwater reach. Case (2) sand bodies demonstrate that in rapidly subsiding foreland basins, cross-shelf palaeovalleys may form down depositional dip from aggradational, distributive fluival strata. Additionally, the genetic relationship between stacked distributary channels and palaeovalleys supports recent models for palaeovalley formation that emphasize diachronous, cut-and-fill during falling stage and lowstands of relative sea level.
      PubDate: 2016-05-22T23:10:55.932657-05:
      DOI: 10.1111/bre.12200
  • Using detrital zircon U-Pb ages to calculate Late Cretaceous sedimentation
           rates in the Magallanes-Austral basin, Patagonia
    • Authors: Theresa M. Schwartz; Julie C. Fosdick, Stephan A. Graham
      Abstract: Determining both short- and long-term sedimentation rates is becoming increasingly important in geomorphic (exhumation and sediment flux), structural (subsidence/flexure) and natural resource (predictive modelling) studies. Determining sedimentation rates for ancient sedimentary sequences is often hampered by poor understanding of stratigraphic architecture, long-term variability in large-scale sediment dispersal patterns and inconsistent availability of absolute age data. Uranium–Lead (U-Pb) detrital zircon (DZ) geochronology is not only a popular method to determine the provenance of siliciclastic sedimentary rocks but also helps delimit the age of sedimentary sequences, especially in basins associated with protracted volcanism. This study assesses the reliability of U-Pb DZ ages as proxies for depositional ages of Upper Cretaceous strata in the Magallanes-Austral retroarc foreland basin of Patagonia. Progressive younging of maximum depositional ages (MDAs) calculated from young zircon populations in the Upper Cretaceous Dorotea Formation suggests that the MDAs are potential proxies for absolute age, and constrain the age of the Dorotea Formation to be ca. 82–69 Ma. Even if the MDAs do not truly represent ages of contemporaneous volcanic eruptions in the arc, they may still indicate progressive-but-lagged delivery of increasingly younger volcanogenic zircon to the basin. In this case, MDAs may still be a means to determine long-term (≥1–2 Myr) average sedimentation rates. Burial history models built using the MDAs reveal high aggradation rates during an initial, deep-marine phase of the basin. As the basin shoaled to shelfal depths, aggradation rates decreased significantly and were outpaced by progradation of the deposystem. This transition is likely linked to eastward propagation of the Magallanes fold-thrust belt during Campanian-Maastrichtian time, and demonstrates the influence of predecessor basin history on foreland basin dynamics.
      PubDate: 2016-04-29T23:19:08.633956-05:
      DOI: 10.1111/bre.12198
  • Tectonic evolution of an intraplate basin: the Lower Tagus Cenozoic Basin,
    • Authors: João Carvalho; Carlos Pinto, Ruben Dias, Taha Rabeh, Luis Torres, José Borges, Ricardo Torres, Henrique Duarte
      Abstract: This article focuses on the reinterpretation of well, seismic reflection, magnetic, gravimetric, surface wave and geological surface data, together with the acquisition of seismic noise data to study the Lower Tagus Cenozoic Basin tectono-sedimentary evolution. For the first time, the structure of the base of the basin in its distal and intermediate sectors is unravelled, which was previously only known in the areas covered by seismic reflection data (distal and small part of intermediate sectors). A complex geometry was found, with three subbasins delimited by NNE-SSW faults and separated by WNW-ESE to NW-SE oriented horsts. In the area covered by seismic reflection data, four horizons were studied: top of the Upper Miocene, Lower to Middle Miocene top, the top of the Palaeogene and the base of Cenozoic. Seismic data show that the major filling of the basin occurred during Upper Miocene. The fault pattern affecting Neogene and Palaeogene units derived here points to that of a polyphasic basin. In the Palaeogene, the Vila Franca de Xira (VFX) and a NNE-SSW trending previously unknown structure (ABC fault zone) probably acted as the major strike-slip fault zones of the releasing bend of a pull-apart basin, which produced a WNW-ESE to NW-SE fault system with transtensional kinematic. During the Neogene, as the stress regime rotated anticlockwise to the present NW-SE to WNW-ESE orientation, the VFX and Azambuja fault zones acted as the major transpressive fault zones and Mesozoic rocks overthrusted Miocene sediments. The reactivation of WNW-ESE to NW-SE fault systems with a dextral strike-slip component generated a series of horsts and grabens and the partitioning of the basin into several subbasins. Therefore, we propose a polyphasic model for the area, with the formation of an early pull-apart basin during the Palaeogene caused by an Iberia–Eurasia plates collision that later evolved into an incipient foreland basin along the Neogene due to a NW-SE to WNE-ESE oriented Iberia–Nubia convergence. This convergence is producing uplift in the area since the Quaternary except for the Tagus estuary subbasin around the VFX fault, where subsidence is observed. This may be due to the locking or the development of a larger component of strike-slip movement of the NNE-SSW to N-S thrust fault system with the exception of the VFX fault, which is more favourably oriented to the maximum compressive stress.
      PubDate: 2016-04-27T23:26:54.328967-05:
      DOI: 10.1111/bre.12193
  • Detrital zircon geochronology of pre- and syncollisional strata, Acadian
           orogen, Maine Appalachians
    • Authors: Dwight C. Bradley; Paul O'Sullivan
      Abstract: The Central Maine Basin is the largest expanse of deep-marine, Upper Ordovician to Devonian metasedimentary rocks in the New England Appalachians, and is a key to the tectonics of the Acadian Orogeny. Detrital zircon ages are reported from two groups of strata: (1) the Quimby, Rangeley, Perry Mountain and Smalls Falls Formations, which were derived from inboard, northwesterly sources and are supposedly older; and (2) the Madrid, Carrabassett and Littleton Formations, which were derived from outboard, easterly sources and are supposedly younger. Deep-water deposition prevailed throughout, with the provenance shift inferred to mark the onset of foredeep deposition and orogeny. The detrital zircon age distribution of a composite of the inboard-derived units shows maxima at 988 and 429 Ma; a composite from the outboard-derived units shows maxima at 1324, 1141, 957, 628, and 437 Ma. The inboard-derived units have a greater proportion of zircons between 450 and 400 Ma. Three samples from the inboard-derived group have youngest age maxima that are significantly younger than the nominal depositional ages. The outboard-derived group does not share this problem. These results are consistent with the hypothesised provenance shift, but they signal potential problems with the established stratigraphy, structure, and (or) regional mapping. Shallow-marine deposits of the Silurian to Devonian Ripogenus Formation, from northwest of the Central Maine Basin, yielded detrital zircons featuring a single age maximum at 441 Ma. These zircons were likely derived from a nearby magmatic arc now concealed by younger strata. Detrital zircons from the Tarratine Formation, part of the Acadian foreland-basin succession in this strike belt, shows age maxima at 1615, 980 and 429 Ma. These results are consistent with three episodes of zircon recycling beginning with the deposition of inboard-derived strata of the Central Maine Basin, which were shed from post-Taconic highlands located to the northwest. Next, southeasterly parts of this succession were deformed in the Acadian orogeny, shedding detritus towards the northwest into what remained of the basin. Finally, by Pragian time, all strata in the Central Maine Basin had been deformed and detritus from this new source accumulated as the Tarratine Formation in a new incarnation of the foreland basin. Silurian-Devonian strata from the Central Maine Basin have similar detrital zircon age distributions to coeval rocks from the Arctic Alaska and Farewell terranes of Alaska and the Northwestern terrane of Svalbard. We suggest that these strata were derived from different segments of the 6500-km-long Appalachian-Caledonide orogen.
      PubDate: 2016-04-08T23:35:37.543896-05:
      DOI: 10.1111/bre.12188
  • Triassic to Early Jurassic climatic trends recorded in the Jameson Land
           Basin, East Greenland: clay mineralogy, petrography and heavy mineralogy
    • Authors: Audrey Decou; Steven D. Andrews, David H. M. Alderton, Andrew Morton
      Abstract: During the Early Triassic the Jameson Land Basin (Central East Greenland) was located around 30° N, in the Northern arid belt, but by the Early Jurassic was positioned at a latitude of approximately 50° N. This study examines the record of this transition through a largely continental succession using clay mineralogy, sedimentology, petrography and heavy mineralogy. The Jameson Land Basin is aligned north–south and is 280 km long and 80 km wide. Following an Early Triassic marine phase the basin was filled by predominantly continental sediments. The Early-to-Late Triassic succession comprises coarse alluvial clastics (Pingo Dal Formation) overlain by a succession of fine-grained evaporite-rich playa/lacustrine sediments (Gipsdalen Formation), indicative of arid climatic conditions. The overlying buff, dolomitic and then red lacustrine mudstones with subordinate sandstones (Fleming Fjord Formation) record reduced aridity. The uppermost Triassic grades into dark organic-rich, and in places coaly, mudstones and buff coarse-grained sandstones of lacustrine origin that belong to the Kap Stewart Group, which spans the Triassic–Jurassic boundary, and appear to record more humid climatic conditions. Clay mineralogy analyses highlight significant variations in the kaolinite/illite ratio, from both mudstone and sandstone samples, through the Triassic and into the earliest Jurassic. Complementary heavy mineral analyses demonstrate that the variations recognised in clay mineralogy and sandstone maturity through the Triassic–Early Jurassic succession are not a product of major provenance change or the effect of significant diagenetic alteration. The observed variations are consistent with sedimentological evidence for a long-term trend towards more humid conditions through the Late Triassic to Early Jurassic, and the suggestion of a significant pluvial episode in the mid-Carnian.
      PubDate: 2016-04-06T06:18:22.007015-05:
      DOI: 10.1111/bre.12194
  • The Asturian Basin within the North Iberian margin (Bay of Biscay):
           seismic characterisation of its geometry and its Mesozoic and Cenozoic
    • Authors: Patricia Cadenas; Gabriela Fernández-Viejo
      Abstract: The distribution and structure of the Mesozoic and Cenozoic cover within the central part of the North Iberian Margin (Bay of Biscay) is analysed based on a dense set of 2D seismic reflection lines and logs. The integration of well data allows the recognition of seven seismostratigraphic units and the construction of a surface that illustrates the 3D morphology of this area at the time of the Jurassic rifting. The study zone comprises what is known as Le Danois Bank, a basement high, and the Asturian Basin, one of the sedimentary basins originated during the Iberian rifting at the end of the Paleozoic. Its development continued with the oceanisation of the Bay of Biscay as a failed arm of the Atlantic rift; later, during the Cenozoic, a drastic change in tectonic regime induced the partial closure of Biscay and building up the Cantabrian−Pyrenean chain along the northern border of Iberia. This compressional period left its imprint in the Asturian Basin sediments in the form of a mild inversion and general uplift. The geometry of the basin bottom appears as an asymmetric bowl thinning out towards the edges, with a main E-W depocenter, separated by E-W striking faults from a secondary one. Those bounding faults show twisted trends in the north, interpreted as a consequence of the compressional period, when a transfer zone in a N-S direction formed between the two E-W striking deformation fronts in Biscay. This study shows that the transfer zone extends further to the west, reaching the longitude of Le Danois Bank. The maximum thickness of the filling within the Asturian Basin is estimated in more than 10 km, deeper than assessed in previous studies. The recognition of frequent halokynetic structures at this longitude is another observation worth to remark. Based on this study, it is suggested that the basin formed on top of a distal basement block of stretched crust limiting with the hyperextended rifted domain of Biscay. This location largely conditioned its deformation during the late compression.
      PubDate: 2016-03-24T06:42:26.30034-05:0
      DOI: 10.1111/bre.12187
  • Sediment partitioning, continental slopes and base-of-slope systems
    • Authors: Bradford E. Prather; Ciaran O'Byrne, Carlos Pirmez, Zoltán Sylvester
      Abstract: Deciphering the role slope topography plays in partitioning sediment on siliciclastic continental slope and base-of-slope systems helps our understanding of slope depositional processes in significant ways: (1) by validation of large-scale depositional process models for continental margins, (2) by validation of numerical basin-scale stratigraphic forward models used to test and deploy source-to-sink (S2S) concepts and (3) by creating models for setting reservoir presence and quality expectations in frontier areas poorly constrained by wells and seismic. A global database consisting of>700 km of drilled stratigraphy provide empirical rock data lacking from most S2S studies. Analysis of calibrated seismic stratigraphic units characterised using the contextual framework laid out in this paper show that both gross depositional environments (GDEs) and sand content occur across slope profiles in systematic ways. The challenge in using these observations to quantify reservoir risk and uncertainty lies with relating the observations to depositional processes that can be used to characterise frontier basins that lack calibration. Depositional process-based understanding encoded in 3D stratigraphic forward models (SFM) can simulate both lithologies and GDEs providing broad predictions for exploration at the scale of an entire basin or slope system. Stratigraphic forward models allow the integration of S2S understanding and provide a framework for testing sediment-partitioning hypotheses in frontier settings. Valid S2S models must balance sediment yield from the source catchments with sinks, and be consistent with basin specific observations. The proportions of GDEs across the slope provide additional validation criteria to ensure the models are plausible.
      PubDate: 2016-03-12T02:31:09.89148-05:0
      DOI: 10.1111/bre.12190
  • Evidence of quaternary transtensional tectonics in the Nekor basin (NE
    • Authors: Manfred Lafosse; Elia d'Acremont, Alain Rabaute, Bernard Mercier de Lépinay, Abdelilah Tahayt, Abdellah Ammar, Christian Gorini
      Abstract: The geodynamic processes in the western Mediterranean are driven by both deep (mantle) processes such as slab-rollback or delamination, oblique plate convergence and inherited structures. The present-day deformation of the Alboran Sea and in particular the Nekor basin area is linked to these coeval effects. The seismically active Nekor basin is an extensional basin formed in a convergent setting at the eastern part of the Rif Chain whose boundaries extend both onshore and offshore Morocco. We propose a new structural model of the Nekor basin based on high-resolution offshore data compiled from recent seismic reflection profiles, swath bathymetry acquisitions and industrial seismic reflection profiles. The new data set shows that the northern limit of the basin is oriented N49° with right-stepping faults from the Bousekkour–Aghbal fault to the sinistral Bokkoya fault zone. This pattern indicates the presence of an inherited left-lateral basement fault parallel to the major inherited Nekor fault. This fault has been interpreted as a Quaternary active left-lateral transfer fault localized on weak structural discontinuities inherited from the orogenic period. Onshore and offshore active faults enclose a rhombohedral tectonic Nekor Basin. Normal faults oriented N155° offset the most recent Quaternary deposits in the Nekor basin, and indicate the transtensional behaviour of this basin. The geometry of these faults suggests a likely rollover structure and the presence at depth of a crustal detachment. Inactive Plio-Quaternary normal faults to the east of the Ras Tarf promontory and geometries of depocentres seem to indicate the migration of deformation from east to west. The local orientations of horizontal stress directions deduced from normal fault orientations are compatible with the extrusion of the Rifian units and coherent with the westward rollback of the Tethyan slab and the localization of the present-day slab detachment or delamination.
      PubDate: 2016-03-03T03:13:54.007979-05:
      DOI: 10.1111/bre.12185
  • Structural evolution of a gravitationally detached normal fault array:
           analysis of 3D seismic data from the Ceduna Sub-Basin, Great Australian
    • Authors: A. G. Robson; R. C. King, S. P. Holford
      Abstract: The growth, interaction and controls on normal fault systems developed within stacked delta systems at extensional delta-top settings have not been extensively examined. We aim to analyse the kinematic, spatial and temporal growth of a Cretaceous aged, thin-skinned, listric fault system in order to further the understanding of how gravity-driven fault segments and fault systems develop and interact at an extensional delta-top setting. Furthermore, we aim to explore the influence of a pre-existing structural framework on the development of gravity-driven normal faults through the examination of two overlapping, spatially and temporally distinct delta systems. To do this, we use three-dimensional (3D) seismic reflection data from the central Ceduna Sub-basin, offshore southern Australia. The seismic reflection data images a Cenomanian-Santonian fault system, and a post-Santonian fault system, which are dip-linked through an intervening Turonian-early Campanian section. Both of these fault systems contain four hard-linked strike assemblages oriented NW–SE (127–307), each composed of 13 major fault segments. The Cenomanian-Santonian fault system detaches at the base of a shale interval of late Albian age, and is characterised by kilometre-scale growth faults in the Cenomanian-Sanontian interval. The post-Santonian fault system nucleated in vertical isolation from the Cenomanian-Santonian fault system. This is evident through displacement minima observed at Turonian-early Campanian levels, which is indicative of vertical segmentation and eventual hard dip-linkage. Our analysis constrains fault growth into four major evolutionary stages: (1) early Cenomanian nucleation and growth of fault segments, resulting from gravitational instability, and with faults detaching on the lower Albian interval; (2) Santonian cessation of growth for the majority of faults; (3) erosional truncation of fault upper tips coincident with the continental breakup of Australia and Antarctica (ca. 83 Ma); (4) Campanian-Maastrichtian reactivation of the underlying Cenomanian-Santonian fault system, inducing the nucleation, growth and consequential dip-linkage of the post-Santonian fault system with the underlying fault system. Our results highlight the along-strike linkage of fault segments and the interaction through dip-linkage and fault reactivation, between two overlapping, spatially and temporally independent delta systems of Cenomanian and late Santonian-Maastrichtian age in the frontier Ceduna Sub-Basin. This study has implications regarding the growth of normal fault assemblages, through vertical and lateral segment linkage, for other stacked delta systems (such as the Gulf of Mexico) where upper delta systems develop over a pre-existing structural framework.
      PubDate: 2016-03-02T04:03:45.942828-05:
      DOI: 10.1111/bre.12191
  • Numerical modelling study of mechanisms of mid-basin salt canopy evolution
           and their potential applications to the Northwestern Gulf of Mexico
    • Authors: Sofie Gradmann; Christopher Beaumont
      Abstract: Salt canopies are present in many of the worldwide large salt basins and are key players in the basins' structural evolution as well as in the development of associated hydrocarbon systems. This study employs 2D finite-element models which incorporate the dynamical interaction of viscous salt and frictional-plastic sediments in a gravity-spreading system. We investigate the general emplacement of salt canopies that form in the centre of a large, autochthonous salt basin. This is motivated by the potential application to a mid-basin canopy in the NW Gulf of Mexico (GoM) that developed in the late Eocene. Three different salt expulsion and canopy formation concepts that have been proposed in the salt-tectonic literature for the GoM are tested. Two of these mechanisms require pre-existing diapirs as precursory structures. We include their evolution in the models to assure a continuous, smooth evolution of the salt-sediment system. The most efficient canopy formation takes place under the squeezed diapir mechanism. Here, shortening of a region containing pre-existing diapirs is absorbed by the salt (the weakest part of the system), which is then expelled onto the seafloor. The expulsion rollover mechanism, which evacuates salt from beneath evolving rollover structures and expels it both laterally and to the surface, was not successfully captured by the numerical models. No rollover structures developed and only minor amounts of allochthonous salt emerged to the seafloor. The breached anticline mechanism requires substantial shortening of salt-cored, pre-weakened folds such that the salt breaches the anticlines and is expelled to the seafloor. The amount of shortening may be too large to occur in the central part of a salt basin, but may explain canopy evolution closer to the distal end of the allochthonous salt. When applying the different concepts to the northwestern GoM, none of the models adequately describes the entire system, yet the squeezed diapir mechanism captures most structural features of the Eocene paleocanopy. It is nevertheless possible that different mechanisms have acted in combination or sequentially in the northwestern GoM.
      PubDate: 2016-03-01T23:38:36.39987-05:0
      DOI: 10.1111/bre.12186
  • Development of sedimentary basins: differential stretching, phase
           transitions, shear heating and tectonic pressure
    • Authors: Ebbe H. Hartz; Sergei Medvedev, Daniel W. Schmid
      Abstract: Classical models of lithosphere thinning predict deep synrift basins covered by wider and thinner post-rift deposits. However, synextensional uplift and/or erosion of the crust are widely documented in nature (e.g. the Base Cretaceous unconformity of the NE Atlantic), and generally the post-rift deposits dominate basins fills. Accordingly, several basin models focus on this discrepancy between observations and the classical approach. These models either involve differential thinning, where the mantle thins more than the crust thereby increasing average temperature of the lithosphere, or focus on the effect of metamorphic reactions, showing that such reactions decrease the density of lithospheric rocks. Both approaches result in less synrift subsidence and increased post-rift subsidence. The synextensional uplift in these two approaches happens only for special cases, that is for a case of initially thin crust, specific mineral assemblage of the lithospheric mantle or extensive differential thinning of the lithosphere. Here, we analyse the effects of shear heating and tectonic underpressure on the evolution of sedimentary basins. In simple 1D models, we test the implications of various mechanisms in regard to uplift, subsidence, density variations and thermal history. Our numerical experiments show that tectonic underpressure during lithospheric thinning combined with pressure-dependent density is a widely applicable mechanism for synextensional uplift. Mineral phase transitions in the subcrustal lithosphere amplify the effect of underpressure and may result in more than 1 km of synextensional erosion. Additional heat from shear heating, especially combined with mineral phase transitions and differential thinning of the lithosphere, greatly decreases the amount of synrift deposits.
      PubDate: 2016-02-26T22:54:04.105965-05:
      DOI: 10.1111/bre.12189
  • Intraplate uplift: new constraints on the Hoggar dome from the Illizi
           basin (Algeria)
    • Authors: Kara L. English; Jonathan Redfern, Giovanni Bertotti, Joseph M. English, Rachida Yahia Cherif
      Abstract: Zones of anomalously high topography within continental interiors, distant from active plate boundaries, are interpreted as being either dynamically supported by viscous flow in the underlying mantle or influenced by plate tectonics. Constraining the models of their genesis requires accurate data on the timing and dimensions of such features. New apatite fission-track and thermal maturity data from the Illizi Basin in Algeria quantify the magnitude and timing of kilometre–scale uplift and exhumation of the northern flank of the Hoggar swell in North Africa. The findings of this study, integrated with previously published thermochronological data, confirm that long-wavelength regional uplift occurred during the Cenozoic extending over a distance in excess of 1500 km from north to south. The uplift, centred on the Hoggar Massif, significantly impacted the flanking Illizi and Tim Mersoï basins. The combination of thermal history modelling and regional stratigraphic observations indicates that the onset of exhumation of the Illizi Basin likely occurred during the Eocene, broadly coincident with magmatism on the Hoggar Massif to the south and the onset of tectonic shortening in the Atlasic belt to the north.
      PubDate: 2016-02-25T04:46:48.259375-05:
      DOI: 10.1111/bre.12182
  • Mechanisms of late Quaternary fault throw-rate variability along the north
           central Gulf of Mexico coast: implications for coastal subsidence
    • Authors: Zhixiong Shen; Nancye H. Dawers, Torbjörn E. Törnqvist, Nicole M. Gasparini, Marc P. Hijma, Barbara Mauz
      Abstract: Quaternary sea-level cycles have caused dramatic depocentre shifts near the mouths of major rivers. The effects of these shifts on fault activity in passive margin settings is poorly known, as no studies have constrained passive margin fault throw-rate variability over 103 to 105 year time scales. Here we present 11 mean throw rates for the Tepetate–Baton Rouge fault zone along the northern Gulf of Mexico coast in southern Louisiana. These data were obtained by optically stimulated luminescence dating over time scales spanning the last interglacial to the late Holocene. The mean throw rate is ca. 0.22 mm year−1 during the late Holocene, ca. 0.03 mm year−1 during the last glacial and at least 0.07 mm year−1 during the last interglacial. Throw rates averaged over the late Pleistocene to present are spatially uniform within our study area. The temporal variability in throw rates suggests that shifts of the Mississippi River depocentre relative to this fault zone, driven by Quaternary sea-level cycles, may have imposed a significant control on fault activity. The late Holocene throw rate is at least in the order of magnitude smaller than the rates of land-surface subsidence in the Mississippi Delta, indicating that this fault zone is not a dominant contributor to subsidence in this region.
      PubDate: 2016-02-23T01:13:15.37639-05:0
      DOI: 10.1111/bre.12184
  • Tectono-sedimentary evolution of the northern Iranian Plateau: insights
           from middle–late Miocene foreland-basin deposits
    • Authors: Paolo Ballato; Francesca Cifelli, Ghasem Heidarzadeh, Mohammad R. Ghassemi, Andrew D. Wickert, Jamshid Hassanzadeh, Guillaume Dupont-Nivet, Philipp Balling, Masafumi Sudo, Gerold Zeilinger, Axel K. Schmitt, Massimo Mattei, Manfred R. Strecker
      Abstract: Sedimentary basins in the interior of orogenic plateaus can provide unique insights into the early history of plateau evolution and related geodynamic processes. The northern sectors of the Iranian Plateau of the Arabia–Eurasia collision zone offer the unique possibility to study middle–late Miocene terrestrial clastic and volcaniclastic sediments that allow assessing the nascent stages of collisional plateau formation. In particular, these sedimentary archives allow investigating several debated and poorly understood issues associated with the long-term evolution of the Iranian Plateau, including the regional spatio-temporal characteristics of sedimentation and deformation and the mechanisms of plateau growth. We document that middle–late Miocene crustal shortening and thickening processes led to the growth of a basement-cored range (Takab Range Complex) in the interior of the plateau. This triggered the development of a foreland-basin (Great Pari Basin) to the east between 16.5 and 10.7 Ma. By 10.7 Ma, a fast progradation of conglomerates over the foreland strata occurred, most likely during a decrease in flexural subsidence triggered by rock uplift along an intraforeland basement-cored range (Mahneshan Range Complex). This was in turn followed by the final incorporation of the foreland deposits into the orogenic system and ensuing compartmentalization of the formerly contiguous foreland into several intermontane basins. Overall, our data suggest that shortening and thickening processes led to the outward and vertical growth of the northern sectors of the Iranian Plateau starting from the middle Miocene. This implies that mantle-flow processes may have had a limited contribution toward building the Iranian Plateau in NW Iran.
      PubDate: 2016-02-17T03:24:50.884036-05:
      DOI: 10.1111/bre.12180
  • Depositional systems in multiphase rifts: seismic case study from the
           Lofoten margin, Norway
    • Authors: Gijs A. Henstra; Robert L. Gawthorpe, William Helland-Hansen, Rodmar Ravnås, Atle Rotevatn
      Abstract: The evolution of depositional systems in multiphase rifts is influenced by the selective reactivation of faults between subsequent rift phases. The Middle Jurassic to Palaeocene tectonic history of the Lofoten margin, a segment of the North Atlantic rift system, is characterised by three distinct rift phases separated by long (>20 Myr) inter-rift periods. The initial rift phase comprised a distinct fault initiation and linkage stage, whereas the later rift phases were characterised by selective reactivation of previously linked through-going faults which resulted in immediate rift climax. Using 2-D and 3-D seismic reflection data in conjunction with shallow core data we present a 100 Myr record of shallow to deep marine depositional environments that includes deltaic clinoform packages, slope aprons and turbidite fans. The rapid re-establishment of major faults during the later rift phases impacts on drainage systems and sediment supply. Firstly, the immediate localisation of strain and accumulation of displacement on few faults results in pronounced footwall uplift and possible fault block rotation along those faults, which makes it more likely for any antecedent fault-transverse depositional systems to become reversed. Secondly, any antecedent axially-sourced depositional systems that are inherited from the foregoing rift phase(s) are likely to be sustained after reactivation because such axial systems have already been directed around fault tips. Hence, the immediate localisation of strain through selective reactivation in the later rift phases restricts fault-transverse sediment supply more than axial sediment supply, which is likely to be a key aspect of the tectono-sedimentary evolution of multiphase rifts.
      PubDate: 2016-02-15T23:20:21.380838-05:
      DOI: 10.1111/bre.12183
  • Cretaceous evolution of the Andean margin between 36°S and 40°S latitude
           through a multi-proxy provenance analysis of Neuquén Basin strata
    • Authors: Andrea Di Giulio; Ausonio Ronchi, Alessio Sanfilippo, Elizabeth A. Balgord, Barbara Carrapa, Victor A. Ramos
      Abstract: During the Cretaceous, the Neuquén Basin transitioned from an extensional back-arc to a retroarc foreland basin. We present a multi-proxy provenance study of Aptian to Santonian (125–84 Ma) continental sedimentary rocks preserved in the Neuquén Basin used to resolve changes of sediment drainage pattern in response to the change in tectonic regime. Sandstone petrology and U–Pb detrital zircon geochronology constrain the source units delivering detritus to the basin; apatite U–Pb and fission track dating further resolve provenance and determine the age and patterns of exhumation of the source rocks. Sandstone provenance records a sharp change from a mixed orogenic source during Aptian time (ca. 125 Ma), to a magmatic arc provenance in the Cenomanian (ca. 100 Ma). We interpret this provenance change as the result of the drainage pattern reorganisation from divergent to convergent caused by tectonic basin inversion. During this inversion and early stages of contraction, a transient phase of uplift and basin erosion, possibly due to continental buckling, caused the pre-Cenomanian unconformity dividing the Lower from Upper Cretaceous strata in the Neuquén Basin. This phase was followed by the development of a retroarc foreland basin characterised by a volcanic arc sediment provenance progressively shifting to a mixed continental basement provenance during Turonian-Santonian (90–84). According to multi-proxy provenance data and lag times derived from apatite fission track analysis, this trend is the result of a rapidly exhuming source within the Cordillera to the west, in response to active compressional tectonics along the western margin of South America, coupled with the increasing contribution of material from the stable craton to the east; this contribution is thought to be the result of the weak uplift and exhumation of the foreland due to eastward migration of the forebulge.
      PubDate: 2016-02-10T06:17:50.372588-05:
      DOI: 10.1111/bre.12176
  • A simplified stress analysis of rising salt domes
    • Authors: Mahdi Heidari; Maria A. Nikolinakou, Peter B. Flemings, Michael R. Hudec
      Abstract: We use a simple analytical model to estimate the stress field in density-driven, rising salt domes and adjacent sediments, and to describe the evolution of these domes. We show that the pressure exerted by the salt pushing out against its wall rocks (the salt pressure) decreases linearly up the flank of the dome, but is always greater than the overburden stress. In fact, the salt pressure normal to the dome boundary is everywhere the maximum principal stress, whereas the hoop stress parallel to the circumference of the dome is the minimum stress. In addition, we quantitatively describe the critical stages of salt dome evolution (initiation, upbuilding, and downbuilding), relating these stages to sedimentation rate and basin thickness. This analysis also shows that even the highest sedimentation rates are unlikely to accumulate enough sediments to bury downbuilding domes as long as the salt supply is unrestricted. Despite the simplicity of the model, its predictions are in good agreement with field observations near salt domes. Overall, our analytical model can provide critical insight into the stress field perturbation in and near rising salt domes and can be used to assess the accuracy of numerical models and field measurements near these domes.
      PubDate: 2016-02-04T23:24:07.414341-05:
      DOI: 10.1111/bre.12181
  • High-resolution evolution of terrigenous sediment yields in the Provence
           Basin during the last 6 Ma: relation with climate and tectonics
    • Authors: Estelle Leroux; Marina Rabineau, Daniel Aslanian, Christian Gorini, Stéphane Molliex, Francois Bache, Cécile Robin, Laurence Droz, Maryline Moulin, Jeffrey Poort, Jean-Loup Rubino, Jean-Pierre Suc
      Abstract: Basin-wide correlation of Messinian units and Plio-Quaternary chronostratigraphic markers (5.3 Ma, 2.6 Ma, 0.9 Ma and 0.45 Ma), the mapping of total sediment thickness and the determination of overall sedimentary volumes enabled us to provide a high-resolution quantitative history of sediment volumes for the last 6 Ma along the Gulf of Lions margin. The results point to (i) a dramatic increase in terrigenous sediment input during the Messinian Salinity Crisis. This increased sedimentation reflects enhanced regional fluvial erosion related to the dramatic fall of Mediterranean base-level. Stronger weathering due to a regional wetter climate probably also increased erosional fluxes. (ii) A sediment input three times higher during the Plio-Quaternary compared to the Miocene seems in agreement with published measurements from World's ocean. However, the timing of this increase being uncertain, it implies that the trigger(s) also remain(s) uncertain. (iii) A decrease in detrital volume around 2.6 Ma is attributed to a regional change in the drainage pattern of rivers in the northwestern Alps. (iv) This study also highlights the Mid-Pleistocene Revolution around 0.9 Ma, which resulted in an almost doubling of sediment input in the Provencal Basin.
      PubDate: 2016-01-25T02:17:38.188793-05:
      DOI: 10.1111/bre.12178
  • Models of the rapid post-rift subsidence in the eastern Qiongdongnan
           Basin, South China Sea: implications for the development of the deep
           thermal anomaly
    • Authors: Xiaobin Shi; Haiyan Jiang, Jun Yang, Xiaoqiu Yang, Hehua Xu
      Abstract: The Qiongdongnan Basin is one of the largest Cenozoic rifted basins on the northern passive margin of the South China Sea. It is well known that since the Late Miocene, approximately 10 Ma after the end of the syn-rift phase, this basin has exhibited rapid thermal subsidence. However, detailed analysis reveals a two-stage anomalous subsidence feature of the syn-rift subsidence deficit and the well-known rapid post-rift subsidence after 10.5 Ma. Heat-flow data show that heat flow in the central depression zone is 70–105 mW m−2, considerably higher than the heat flow (85 mW m−2 in the eastern basin. We used a numerical model of coupled geothermal processes, lithosphere thinning and depositional processes to analyse the origin of the anomalous subsidence pattern. Numerical analysis of different cases shows that the stretching factor βs based on syn-rift sequences is less than the observed crustal stretching factor βc, and if the lithosphere is thinned with βc during the syn-rift phase (before 21 Ma), the present basement depth can be predicted fairly accurately. Further analysis does not support crustal thinning after 21 Ma, which indicates that the syn-rift subsidence is in deficit compared with the predicted subsidence with the crustal stretching factor βc. The observed high heat flow in the central depression zone is caused by the heating of magmatic injection equivalently at approximately 3–5 Ma, which affected the eastern basin more than the western basin, and the Neogene magmatism might be fed by the deep thermal anomaly. Our results suggest that the causes of the syn-rift subsidence deficit and rapid post-rift subsidence might be related. The syn-rift subsidence deficit might be caused by the dynamic support of the influx of warmer asthenosphere material and a small-scale thermal upwelling beneath the study area, which might have been persisting for about 10 Ma during the early post-rift phase, and the post-rift rapid subsidence might be the result of losing the dynamic support with the decaying or moving away of the deep thermal source, and the rapid cooling of the asthenosphere. We concluded that the excess post-rift subsidence occurs to compensate for the syn-rift subsidence deficit, and the deep thermal anomaly might have affected the eastern Qiongdongnan Basin since the Late Oligocene.
      PubDate: 2016-01-25T02:14:53.99601-05:0
      DOI: 10.1111/bre.12179
  • Subsurface fluid flow in the deep-water Kwanza Basin, offshore Angola
    • Authors: Christophe Serié; Mads Huuse, Niels H. Schødt, James M. Brooks, Alan Williams
      Pages: 149 - 179
      Abstract: Integrated analysis of high-quality three-dimensional (3D) seismic, seabed geochemistry, and satellite-based surface slick data from the deep-water Kwanza Basin documents the widespread occurrence of past and present fluid flow associated with dewatering processes and hydrocarbon migration. Seismic scale fluid flow phenomena are defined by seep-related seafloor features including pockmarks, mud or asphalt volcanoes, gas hydrate pingoes, as well as shallow subsurface features such as palaeo-pockmarks, direct hydrocarbon indicators (DHIs), pipes and bottom-simulating reflections (BSRs). BSR-derived shallow geothermal gradients show elevated temperatures attributed to fluid advection along inclined stratigraphic carrier beds around salt structures in addition to elevated shallow thermal anomalies above highly conductive salt bodies. Seabed evidences of migrated thermogenic hydrocarbons and surface slicks are used to differentiate thermogenic hydrocarbon migration from fluid flow processes such as dewatering and biogenic gas migration. The analysis constrains the fluid plumbing system defined by the three-dimensional distribution of stratigraphic carriers and seal bypass systems through time. Detailed integration and iterative interpretation have confirmed the presence of mature source rock and effective migration pathways with significant implications for petroleum prospectivity in the post-salt interval. Integration of seismic, seabed geochemistry and satellite data represents a robust method to document and interpret fluid flow phenomena along continental margins, and highlights the importance of integrated fluid flow studies with regard to petroleum exploration, submarine geohazards, marine ecosystems and climate change.
      PubDate: 2016-01-20T06:32:31.361189-05:
      DOI: 10.1111/bre.12169
  • Fractionation of grain size in terrestrial sediment routing systems
    • Authors: Philip A. Allen; Nikolaos A. Michael, Mitchall D’Arcy, Duna C. Roda-Boluda, Alexander C. Whittaker, Robert A. Duller, John J. Armitage
      Pages: 180 - 202
      Abstract: Sediment is fractionated by size during its cascade from source to sink in sediment routing systems. It is anticipated, therefore, that the grain size distribution of sediment will undergo down-system changes as a result of fluvial sorting processes and selective deposition. We assess this hypothesis by comparing grain size statistical properties of samples from within the erosional source region with those that have undergone different amounts of transport. A truncated Pareto distribution describes well the coarser half of the clast size distribution of regolith, coarse channel bed sediment and proximal debris flows (particularly their levees), as well as the coarser half of the clast size distribution of gravels that have undergone considerable amounts of transport in rivers. The Pareto shape parameter a evolves in response to mobilization, sediment transport and, importantly, the selective extraction of particles from the surface flow to build underlying stratigraphy. A goodness of fit statistic, the Kolmogorov–Smirnov vertical difference, illustrates the closeness of the observed clast size distributions to the Pareto, Weibull and log-normal models as a function of distance from the depositional apex. The goodness of fit of the particle size distribution of regolith varies with bedrock geology. Bedload sediment at catchment outlets is fitted well by the log-normal and truncated Pareto models, whereas the exponential Weibull model provides a less good fit. In the Eocene Escanilla palaeo-sediment routing system of the south-central Pyrenees, the log-normal and truncated Pareto models provide excellent fits for distances of up to 80 km from the depositional apex, whereas the Weibull fit progressively worsens with increasing transport distance. A similar trend is found in the Miocene–Pliocene gravels of the Nebraskan Great Plains over a distance of>300 km. Despite the large fractionation in mean grain size and gravel percentage from source region to depositional sink, particle size distributions therefore appear to maintain log-normality over a wide range of transport distance. Use of statistical models enables down-system fractionation of sediment released from source regions to be better understood and predicted and is a potentially valuable tool in source-to-sink approaches to basin analysis.
      PubDate: 2016-01-05T04:22:36.371406-05:
      DOI: 10.1111/bre.12172
  • A record of the Messinian salinity crisis in the eastern Ionian
           tectonically active domain (Greece, eastern Mediterranean)
    • Authors: Vasileios Karakitsios; Marco Roveri, Stefano Lugli, Vinicio Manzi, Rocco Gennari, Assimina Antonarakou, Maria Triantaphyllou, Konstantina Agiadi, George Kontakiotis, Nefeli Kafousia, Marc Rafelis
      Pages: 203 - 233
      Abstract: This integrated study (field observations, micropalaeontology, magnetostratigraphy, geochemistry, borehole data and seismic profiles) of the Messinian–Zanclean deposits on Zakynthos Island (Ionian Sea) focuses on the sedimentary succession recording the pre-evaporitic phase of the Messinian salinity crisis (MSC) through the re-establishment of the marine conditions in a transitional area between the eastern and the western Mediterranean. Two intervals are distinguished through the palaeoenvironmental reconstruction of the pre-evaporitic Messinian in Kalamaki: (a) 6.45–6.122 Ma and (b) 6.122–5.97 Ma. Both the planktonic foraminifer and the fish assemblages indicate a cooling phase punctuated by hypersalinity episodes at around 6.05 Ma. Two evaporite units are recognized and associated with the tectonic evolution of the Kalamaki–Argassi area. The Primary Lower Gypsum (PLG) unit was deposited during the first MSC stage (5.971–5.60 Ma) in late-Messinian marginal basins within the pre-Apulian foreland basin and in the wedge-top (
      PubDate: 2016-01-13T04:39:56.994641-05:
      DOI: 10.1111/bre.12173
  • Late Quaternary aggradation rates and stratigraphic architecture of the
           southern Po Plain, Italy
    • Authors: Luigi Bruno; Alessandro Amorosi, Paolo Severi, Bianca Costagli
      Pages: 234 - 248
      Abstract: The Po River Basin, where accumulation and preservation of thick sedimentary packages are enhanced by high rates of tectonic subsidence, represents an ideal site to assess the relations between vertical changes in stratigraphic architecture and sediment accumulation rates. Based on a large stratigraphic database, a markedly contrasting stratigraphy of Late Pleistocene and Holocene deposits is reconstructed from the subsurface of the modern alluvial and coastal plains. Laterally extensive fluvial channel bodies and related pedogenically modified muds of latest Pleistocene age are unconformably overlain by Holocene overbank fines, grading seaward into paralic and nearshore facies associations. In the interfluvial areas, a stiff paleosol, dating at about 12.5–10 cal ky BP, marks the Pleistocene–Holocene boundary. Across this paleosol, aggradation rates (ARs) from 16 radiocarbon-dated cores invariably show a sharp increase, from 0.1–0.9 mm year−1 to 0.9–2.9 mm year−1. Comparatively lower Pleistocene values are inferred to reflect fluvial activity under a low-accommodation (lowstand and early transgressive) regime, whereas higher ARs during the Holocene are related to increasing accommodation under late transgressive and highstand conditions. Holocene sediment accumulation patterns vary significantly from site to site, and do not exhibit common trends. Very high accumulation rates (20–60 mm year−1) are indicated by fluvial channel or progradational delta facies, suggesting that extremely variable spatial distribution of Holocene ARs was primarily controlled by autogenic processes, such as fluvial channel avulsion or delta lobe switching. Contrasting AR between uppermost Pleistocene and Holocene deposits also are reported from the interfluves of several coeval, alluvial-coastal plain systems worldwide, suggesting a key control by allogenic processes. Sediment accumulation curves from adjacent incised valley fills show, instead, variable shapes as a function of the complex mechanisms of valley formation and filling.
      PubDate: 2016-01-07T06:32:43.134105-05:
      DOI: 10.1111/bre.12174
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