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  Subjects -> GEOGRAPHY (Total: 493 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
40 [degrees] South     Full-text available via subscription   (Followers: 1)
AAG Review of Books     Hybrid Journal   (Followers: 2)
AbeÁfrica : Revista da Associação Brasileira de Estudos Africanos     Open Access  
ACME : An International Journal for Critical Geographies     Open Access   (Followers: 1)
Acta Universitatis Lodziensis : Folia Geographica Socio-Oeconomica     Open Access   (Followers: 1)
Adam Academy : Journal of Social Sciences / Adam Akademi : Sosyal Bilimler Dergisi     Open Access   (Followers: 3)
Advances in Cartography and GIScience of the ICA     Open Access   (Followers: 3)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 20)
Advances in Statistical Climatology, Meteorology and Oceanography     Open Access   (Followers: 11)
Africa Insight     Full-text available via subscription   (Followers: 16)
Africa Spectrum     Open Access   (Followers: 16)
African Geographical Review     Hybrid Journal   (Followers: 2)
Afrika Focus     Open Access   (Followers: 1)
AGORA Magazine     Open Access   (Followers: 2)
Agronomía & Ambiente     Open Access   (Followers: 1)
AGU Advances     Open Access   (Followers: 1)
All Earth     Open Access   (Followers: 3)
American Journal of Geographic Information System     Open Access   (Followers: 14)
American Journal of Human Ecology     Open Access   (Followers: 11)
American Journal of Rural Development     Open Access   (Followers: 6)
Amerika     Open Access   (Followers: 1)
Anales de Geografía de la Universidad Complutense     Open Access  
Anatoli     Open Access  
Annales Universitatis Paedagogicae Cracoviensis / Studia de Cultura     Open Access  
Annals of GIS     Open Access   (Followers: 31)
Annals of the American Association of Geographers     Hybrid Journal   (Followers: 43)
Annual Review of Marine Science     Full-text available via subscription   (Followers: 13)
Antipode     Hybrid Journal   (Followers: 65)
Anuario     Open Access  
Applied Geography     Hybrid Journal   (Followers: 40)
Applied Geomatics     Hybrid Journal   (Followers: 4)
Ar@cne     Open Access  
Arctic     Open Access   (Followers: 6)
Arctic Science     Open Access   (Followers: 7)
Area Development and Policy     Hybrid Journal   (Followers: 1)
Asia Policy     Full-text available via subscription   (Followers: 6)
Asian Geographer     Hybrid Journal   (Followers: 5)
Asian Journal of Geographical Research     Open Access   (Followers: 2)
Ateneo Korean Studies Conference Proceedings     Open Access  
Atmospheric Measurement Techniques (AMT)     Open Access   (Followers: 19)
Atmospheric Measurement Techniques Discussions (AMTD)     Open Access   (Followers: 10)
Aurora Journal     Full-text available via subscription  
Australian Antarctic Magazine     Free   (Followers: 5)
Australian Geographer     Hybrid Journal   (Followers: 7)
Bandung : Journal of the Global South     Open Access   (Followers: 1)
Barn : Forskning om barn og barndom i Norden     Open Access  
Baru : Revista Brasileira de Assuntos Regionais e Urbanos     Open Access  
Belgeo     Open Access   (Followers: 2)
Biblio3W : Revista Bibliográfica de Geografía y Ciencias Sociales     Open Access  
Biogeographia : The Journal of Integrative Biogeography     Open Access   (Followers: 2)
BioRisk     Open Access   (Followers: 2)
Boletim Campineiro de Geografia     Open Access  
Boletim de Ciências Geodésicas     Open Access  
Boletim Gaúcho de Geografia     Open Access  
Boletim Goiano de Geografia     Open Access  
Boletín de Estudios Geográficos     Open Access  
Boletín de la Asociación de Geógrafos Españoles     Open Access  
Brill Research Perspectives in Map History     Full-text available via subscription   (Followers: 1)
Buildings & Landscapes: Journal of the Vernacular Architecture Forum     Full-text available via subscription   (Followers: 13)
Bulletin de la Société Géographique de Liège     Open Access  
Bulletin de l’association de géographes français     Open Access   (Followers: 1)
Bulletin of Geography. Physical Geography Series     Open Access   (Followers: 4)
Bulletin of Geography. Socio-economic Series     Open Access   (Followers: 3)
Bulletin of Geosciences     Open Access   (Followers: 12)
Bulletin of the Ecological Society of America     Open Access   (Followers: 4)
Bulletin of the Serbian Geographical Society     Open Access  
Caderno de Geografia     Open Access  
Cahiers Balkaniques     Open Access   (Followers: 2)
Cahiers Charlevoix : Études franco-ontariennes     Full-text available via subscription  
Cahiers franco-canadiens de l'Ouest     Full-text available via subscription   (Followers: 2)
California Italian Studies Journal     Full-text available via subscription   (Followers: 7)
Canadian Journal of Latin American and Caribbean Studies     Hybrid Journal   (Followers: 10)
Canadian Journal of Soil Science     Full-text available via subscription   (Followers: 11)
Cardinalis     Open Access  
Carnets de géographes     Open Access  
Cartographic Journal     Hybrid Journal   (Followers: 9)
Cartographic Perspectives     Open Access   (Followers: 2)
Cartographica : The International Journal for Geographic Information and Geovisualization     Full-text available via subscription   (Followers: 17)
Cartography and Geographic Information Science     Hybrid Journal   (Followers: 32)
Check List : The Journal of Biodiversity Data     Open Access   (Followers: 2)
China : An International Journal     Full-text available via subscription   (Followers: 20)
Climate and Development     Hybrid Journal   (Followers: 35)
Climate Change Economics     Hybrid Journal   (Followers: 52)
Comparative Cultural Studies : European and Latin American Perspectives     Open Access   (Followers: 5)
Computational Geosciences     Hybrid Journal   (Followers: 16)
Computational Urban Science     Open Access   (Followers: 1)
Confins     Open Access  
Conjuntura Austral : Journal of the Global South     Open Access   (Followers: 2)
Coolabah     Open Access  
Creativity Studies     Open Access   (Followers: 5)
Critical Romani Studies     Open Access  
Crossings : Journal of Migration & Culture     Hybrid Journal   (Followers: 16)
Cuadernos de Desarrollo Rural     Open Access  
Cuadernos de Geografía : Revista Colombiana de Geografía     Open Access  
Cuadernos de Geografía de la Universitat de València     Open Access  
Cuadernos de Investigación Geográfica / Geographical Research Letters     Open Access  
Cuadernos Inter.c.a.mbio sobre Centroamérica y el Caribe     Open Access   (Followers: 1)
Current Research in Geoscience     Open Access   (Followers: 5)
Dela     Open Access  
Dialogues in Human Geography     Hybrid Journal   (Followers: 20)
Didáctica Geográfica     Open Access  
DIE ERDE : Journal of the Geographical Society of Berlin     Open Access   (Followers: 1)
Documenti Geografici     Open Access  
Documents d'Anàlisi Geogràfica     Open Access  
Doğu Coğrafya Dergisi : Eastern Geographical Review     Open Access  
DRd - Desenvolvimento Regional em debate     Open Access  
Earth System Governance     Open Access   (Followers: 1)
Earth Systems and Environment     Hybrid Journal   (Followers: 3)
East/West : Journal of Ukrainian Studies     Open Access  
Eastern European Countryside     Open Access   (Followers: 2)
Economic and Regional Studies / Studia Ekonomiczne i Regionalne     Open Access  
Economic Geography     Hybrid Journal   (Followers: 42)
Économie rurale     Open Access   (Followers: 3)
Ecosystems and People     Open Access   (Followers: 4)
Entorno Geográfico     Open Access  
Environment & Ecosystem Science     Open Access   (Followers: 3)
Environmental and Sustainability Indicators     Open Access   (Followers: 7)
Environmental Science : Atmospheres     Open Access  
Environmental Science and Sustainable Development : International Journal Of Environmental Science & Sustainable Development     Open Access   (Followers: 13)
Environmental Smoke     Open Access  
Ería : Revista Cuatrimestral de Geografía     Open Access  
Espacio y Desarrollo     Open Access  
Espacios : Revista de |Geografía     Open Access  
Espaço & Economia : Revista Brasileira de Geografia Econômica     Open Access  
Espaço Aberto     Open Access  
Espaço e Cultura     Open Access  
Espaço e Tempo Midiáticos     Open Access  
Estudios Geográficos     Open Access   (Followers: 1)
Estudios Socioterritoriales : Revista de Geografía     Open Access  
Ethnobiology Letters     Open Access  
Ethnoscientia : Brazilian Journal of Ethnobiology and Ethnoecology     Open Access  
eTropic : electronic journal of studies in the tropics     Open Access  
Études internationales     Full-text available via subscription   (Followers: 1)
Études rurales     Open Access   (Followers: 2)
Études/Inuit/Studies     Full-text available via subscription  
European Bulletin of Himalayan Research     Open Access   (Followers: 10)
European Countryside     Open Access   (Followers: 1)
European Spatial Research and Policy     Open Access   (Followers: 9)
Evolutionary Human Sciences     Open Access   (Followers: 5)
Fennia : International Journal of Geography     Open Access   (Followers: 1)
Finisterra : Revista Portuguesa de Geografia     Open Access  
Fire Ecology     Open Access   (Followers: 3)
Florida Geographer     Open Access   (Followers: 1)
Focus on Geography     Partially Free   (Followers: 5)
Forum Geografi     Open Access  
Frontera Norte     Open Access  
GEM - International Journal on Geomathematics     Hybrid Journal   (Followers: 1)
Genre & histoire     Open Access   (Followers: 4)
Geo : Geography and Environment     Open Access   (Followers: 9)
Geo UERJ     Open Access  
Geo-Image     Open Access   (Followers: 1)
Geo-spatial Information Science     Open Access   (Followers: 8)
GeoArabia     Hybrid Journal  
Géocarrefour     Open Access  
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (Followers: 34)
Geochronometria     Open Access   (Followers: 1)
Geoderma Regional : The International Journal for Regional Soil Research     Full-text available via subscription   (Followers: 4)
Geodesy and Cartography     Open Access   (Followers: 2)
Geoforum Perspektiv     Open Access   (Followers: 1)
Geofronter     Open Access  
Geografares     Open Access  
Geografisk Tidsskrift-Danish Journal of Geography     Hybrid Journal   (Followers: 3)
Geografiska Annaler, Series A : Physical Geography     Hybrid Journal   (Followers: 4)
Geographia     Open Access   (Followers: 3)
Geographica Helvetica     Open Access   (Followers: 13)
Geographical Analysis     Hybrid Journal   (Followers: 11)
Geographical Education     Full-text available via subscription   (Followers: 2)
Geographical Journal of Nepal     Open Access  
Geographical Research     Hybrid Journal   (Followers: 11)
Geographical Review     Hybrid Journal   (Followers: 13)
Geographicalia     Open Access  
Géographie et cultures     Open Access   (Followers: 3)
Geography and Natural Resources     Hybrid Journal   (Followers: 10)
Geography and Sustainability     Open Access   (Followers: 3)
Geography Compass     Hybrid Journal   (Followers: 18)
GeoHumanities     Hybrid Journal   (Followers: 2)
GeoInformatica     Hybrid Journal   (Followers: 7)
Geoinformatics & Geostatistics     Hybrid Journal   (Followers: 13)
Geoinformatics FCE CTU     Open Access   (Followers: 7)
Geoingá : Revista do Programa de Pós-Graduação em Geografia     Open Access  
GeoJournal     Hybrid Journal   (Followers: 11)
GEOMATICA     Hybrid Journal   (Followers: 1)
Geomatics, Natural Hazards and Risk     Open Access   (Followers: 14)
GEOmedia     Open Access   (Followers: 1)
Geopauta : Revista de Geografia da Universidade Estadual do Sudoeste da Bahia     Open Access  
Geophysical Research Letters     Full-text available via subscription   (Followers: 199)
Geoplanning : Journal of Geomatics and Planning     Open Access   (Followers: 5)
GeoScape     Open Access  
Geosciences Journal     Hybrid Journal   (Followers: 11)
Geosphere     Open Access   (Followers: 2)
GEOUSP : Espaço e Tempo     Open Access  
Ghana Journal of Geography     Open Access   (Followers: 11)
Ghana Studies     Full-text available via subscription   (Followers: 15)
GIScience & Remote Sensing     Open Access   (Followers: 55)
Global Challenges     Open Access   (Followers: 2)
Global Sustainability     Open Access   (Followers: 5)
Globe, The     Full-text available via subscription   (Followers: 4)
GPS Solutions     Hybrid Journal   (Followers: 28)
Grafo Working Papers     Open Access  
HiN : Alexander von Humboldt im Netz. Internationale Zeitschrift für Humboldt-Studien     Open Access  

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Geosciences Journal
Journal Prestige (SJR): 0.381
Citation Impact (citeScore): 1
Number of Followers: 11  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1598-7477 - ISSN (Online) 1226-4806
Published by Springer-Verlag Homepage  [2467 journals]
  • Geochronology, geochemistry, Hf isotope, and electron probe analysis of
           the diorite in the Jianhei Mountain, East Kunlun Orogenic Belt, China, and
           their geological significance

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      Abstract: Abstract The Eastern Kunlun orogenic belt (EKOB) is located in southern margin of the Qaidam Basin. After the evolution of the Proto-Tethys Ocean and the Paleo-Tethys Ocean, the geological structure is complex and diverse in the EKOB. Herein, the results of geochronological, geochemical, Hf isotope, and electron probe analyses are presented for the Jianhei Mountain diorite in the EKOB. The results of the geochemical studies show that the rock is enriched in Al, Ca, and Fe, depleted in Ni and Cr, and contains moderate amounts of Mg. The samples exhibit a high degree of fractionation of light and heavy rare earth elements (REEs), with the light REEs being enriched, and the heavy REEs being depleted. Furthermore, the samples are enriched in the large ion lithophile elements, and depleted in the high field strength elements. The Jianhei Mountain diorite yields a weighted mean zircon U-Pb dating age of 251.3 ±1.8 Ma, which is in the Early Triassic. The Zircon Hf isotope analysis gives a zircon (Eu/Eu⋆)N value that ranges from −5.2 to −3.3, and the two-stage model age is 1244–1342 Ma. Combined with other geochemical characteristics, it can be concluded that the source area of the Jianhei Mountain diorite is dominated by Mesoproterozoic crustal materials, with a small amount of mantle material involved in the petrogenetic process. In addition, the results of electron probe micro-analysis show that the MgO content of the hornblende is 9.57–10.40%, the Mg/(Mg + Fe2+) ratio is 0.49–0.52, the Mg content is 2.15–2.31, the Ca content is 1.71–1.80, and the total of Fe3+ + Fe2+ is 2.04–2.17. The MgO content of the biotite is 8.47–9.31%, and the Fe2+/(Mg + Fe2+) ratio is 0.50–0.52. In accordance with previous studies, the mineral compositions of the hornblende and biotite are closely related to their genesis. It can be concluded that the hornblende and biotite of the Jianhei Mountain diorite have the characteristics of a crust-mantle mixed source. Overall, the present authors believe that the Jianhei Mountain diorite is the product of partial melting of the lower crust in the tectonic background of the northward subduction of the Paleo-Tethys Ocean, with a small amount of mantle material involved in the petrogenetic process.
      PubDate: 2022-12-01
       
  • Surface sediment geochemistry for understanding the recent sedimentary
           environment in northwestern Karnataka, south India

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      Abstract: Abstract Geochemical study of 195 stream sediment samples (in less than 75 µm grain size) distributed in parts of Belgaum, Dharwad, and Uttar Kanada districts (bounded by latitudes from 15°15′00″ to 15°30′00″ and longitudes from 74°30′00″ to 74°45′00″) were studied for the major oxide, trace and rare earth element content. The objective of this study is to understand the recent sedimentary environment by establishing the generalized climatic conditions, chemical weathering, sediment sorting and recycling, sediment sources, and the tectonic setting of the study area. Geochemical signatures of the sediments indicate a semi-arid to the moist climate in the study area. Geochemical proxies show that annual rainfall in the study area varies from 378 to 692 mm, higher in the western part compared to that in the eastern side. The chemical index of alteration (67.70–94.01) and chemical index of weathering (76.24–97.37) collectively suggest moderate to high chemical weathering. Studied samples show a wide variation in major oxides and trace elements. Fe2O3, MnO, K2O, P2O5, Rb, Zr, and Sc display a positive correlation with Al2O3 confirming their possible hydraulic fractionation. Zr/Sc vs. Th/Sc plot and correlation between CIA vs. Al2O3 indicate strong sediment recycling and sorting. Bulk geochemistry data suggests the involvement of granite and other felsic rocks, intermediate and mafic rocks as the sources of surface sediments. Our observations are very well matching with the geology of the area. Major and trace element set of discrimination diagrams demarcates the passive margin settings for the studied samples, except for a few samples plotting into an active continental margin tectonic settings.
      PubDate: 2022-12-01
       
  • Formation of talc fault gouge analog using high-energy ball mill

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      Abstract: Abstract Fault gouge, located in highly deformed fault cores, shows substantial particle size reduction and loss of crystallinity, which could affect the physicochemical properties and thus control the slip behavior and earthquake stability of a fault. To systematically investigate the effect of deformed fault gouge on fault slip behavior in laboratory-scale experiments, a fault gouge analog with variable particle size and crystallinity is required. However, the systematic study for formation of a fault gouge analog (i.e., controlling the particle size and crystallinity) was not performed well. In this study, we investigated the effect of the rotation speed of a high-energy ball mill on particle size reduction rate and degree of amorphization. As the rotation speed increased from 500 to 2000 rpm, the comminution rate linearly increased, and reached a reduced particle size limit. The degree of amorphization and its rate also increased with increasing rotation speed. Upon grinding, the X-ray diffraction (XRD) peaks markedly decreased and reached critical amorphization points within 120 min, except for the case of grinding with a rotation speed of 500 rpm. Talc ground with a rotation speed of 500 rpm did not reach steady-state in mechanical amorphization after 360 min of grinding, thus necessitating prolonged grinding for further amorphization. A comparison of talc powders having similar specific surface areas, but ground at different rotation speeds, shows that grinding with a higher rotation speed for a shorter duration preserves the crystalline structure relatively well compared with grinding at a lower rotation speed for a longer duration. These results indicate that optimizing the grinding rotation speed facilitates the formation of talc fault gouge analogs with systematically varying particle size and crystallinity. The specific surface area of talc increased from 6.1 to 365 m2/g, and the degree of crystallinity decreased from approximately 75% to 11%. Our results indicate that an artificial talc fault gouge can be prepared by varying the particle size and crystallinity using a high-energy ball mill.
      PubDate: 2022-12-01
       
  • A machine learning algorithm with random forest for recognizing hidden
           control factors from seismic fault distribution

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      Abstract: Abstract Stress interaction among many faults in earthquake prone region is strongly affected by the spatial distribution of faults. To build a robust Machine Learning (ML) algorithm for finding hidden relationships between fault distribution and its controlling factors, the performance of ML in dependence of various parameters, such as the complexity and data size of the fault distribution, needs to be investigated. We have, therefore, developed an ML algorithm by combining Principal Component Analysis (PCA) with a Random Forest (RF) to unveil the controlling factors on seismic fault distribution. We synthesized fault images for training of RF classifier ND (> 10,000) fault images, which scattered the faults in a square with R km R km. R, ranging from 200 km to 600 km, is a controlling factor of fault distribution. PCA extracts the dominant features of the seismic fault images to supply the refined training data to the RF. This leads to a dimensional reduction of the data. We tested the influence of the number of principal components (NP) on PCA performance in retaining the information. Larger and more variable R values (i.e., a more complicated fault distribution) with larger amounts of training data required more principal components for a full preservation of the original data. We quantified the optimized NP/ND ratio for an efficient RF classifier, which was about ∼0.1 for the evaluating efficacy of the PCA. This showed that the RF classifiers is effective in predicting R values depending on the fault zone with R km R km and not on specific fault locations. We propose that a small NP, equivalent to ∼10% of the training data, suffices for training accurately RF classifier for fault distributions, which can reduce the complexity of fault distribution to understand stress interaction among many faults.
      PubDate: 2022-11-19
       
  • Evolution process of W−Pb−Zn mineralizing fluid: implication from the
           carbonate-hosted Subok deposit in the Hwanggangri mineralized district,
           South Korea

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      Abstract: Abstract The evolutionary process and spatiotemporal variation of W and Pb−Zn mineralizing fluids was investigated for the Subok deposit, a representative W−Pb−Zn deposit in the Hwanggangri mineralized district (HMD) in South Korea. The deposit was emplaced in Paleozoic carbonate rocks, which were intruded by Cretaceous Muamsa granite. The paragenetic sequence is characterized by early pyrrhotite-scheelite-arsenopyrite and late arsenopyrite-sphalerite-galena assemblages. In terms of spatial distribution, pyrrhotite and scheelite were dominant in the lower part, whereas arsenopyrite mainly occurred in the upper part. The upward increasing δ34SH2S values of ore-bearing fluids range from 1.0 to 5.9‰, corresponding to a magmatic origin. In this deposit, according to As content of arsenopyrite, fluid inclusion, and sulfur stable isotope, the early W and late Pb−Zn mineralization was controlled by decreasing temperature (425–590 to 380–450 °C), pressure (0.54–5.13 to 0.38–3.99 kbar), and sulfur fugacity of the uprising ore-bearing fluids. In the HMD, wolframite and molybdenite mainly occur in the granitic rock, whereas scheelite is precipitated in the carbonate host rock under decreasing oxygen fugacity, salinity, and pH, and the input of Ca from the host rock in the distal area. Late Pb−Zn mineralization was achieved by decreasing temperature and pressure of ore-bearing fluids and mixing with meteoric water in the distal area. The mineral zonation and physicochemical variation of W and Pb−Zn mineralizations can be applicable as indicators for the exploration of ore deposits.
      PubDate: 2022-11-17
       
  • Non-invasive mineral analysis of pigments of wall paintings in the
           Sungseonjeon Hall

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      Abstract: Abstract Non-destructive investigations were conducted by applying various analysis methods to investigate the production period of six wall paintings of the Sungseonjeon Hall in the royal tomb of King Suro, Historic Site No. 73 in Gimhae, South Korea. Portable microscopy and portable X-ray fluorescence analysis were performed in situ, and Raman spectroscopy and X-ray diffraction were applied to small fragments of painting layers. From microscopic observations, the size and arrangement of the mineral pigment particles used in the wall paintings were confirmed to be suitable for non-destructive analysis. Among the major elements and mineral phases detected in the wall paintings that are regarded to be earlier works (late 17th century), talc, minium with cinnabar, atacamite with botallackite, and lazurite have been detected in white, red, green, and blue specimens, respectively, confirming the use of traditional mineral pigments employed since ancient times. In contrast, in wall paintings added later (after the 19th century), anatase, minium, lavendulan with cornwallite, and lazurite were detected, along with crocoite in yellow specimens. These results indicate the existence of modern traces through synthetic pigments such as titanium white, emerald green, and chrome yellow, which were introduced by the West with the passage of time.
      PubDate: 2022-11-17
       
  • A method of determining optimum sections suitable for the simultaneous
           extraction of coalbed methane from 3# and 15# coal seams in the
           Wangcun-Xiadian Block and its application

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      Abstract: Abstract In addition to reservoir geological factors, economic benefits are another important factor that determines the feasibility of co-layer drainage. In view of this, this paper takes the 3# and 15# coal seams in the Wangcun-Xiadian block of the Qinshui Basin (Shanxi Province, China) as the research object, adopts the step-by-step method to summarize the geological influencing factors and thresholds of the drainage of the total combined seam, and eliminates the unsuitable geological conditions blocks for layer development. Using the productivity numerical simulation software combined with the constructed economic evaluation model, the suitable blocks for co-production in this zone were identified. The one-sidedness of the evaluation results caused by only considering the geological reservoir conditions is avoided, and the practicability of the evaluation results is guaranteed. The results indicate that the difference of formation liquid supply capacity between the two layers of coal is the key factor affecting combined layer drainage. When the gas content of 3# coal seam is 8,15m3/t and the post-fracturing permeability exceeds 5.17 × 10−3 µm2 and 1.13 × 10−3 µm2 respectively, it is suitable for single development of 3# coal seam. When the geological conditions for commingled production are met, it is suitable for simultaneous development of 3# and 15# when the permeability after fracturing exceeds 6.27 × 10−3 µm2 and 1.31 × 10−3 µm2 respectively under the same gas content. The study methodology considers both geological reservoirs and economic benefits, which can more objectively and accurately evaluate the suitable development blocks.
      PubDate: 2022-11-17
       
  • The use of magnetic and geoelectrical methods to locate buried ancient
           artificial canals and wells around the cultural heritage of Indrapatra
           Fort, Aceh, Indonesia

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      Abstract: Abstract The application of magnetic and geoelectrical methods for archaeological study is presented in this paper. The study was intended to map near-surface structures around the Indrapatra Fort, the 16th-century fortification built during the Early Aceh Sultanate in the north of Sumatra. Some of the structures around the fort have been buried after the 2004 Indian Ocean Tsunami or even by previous paleotsunami deposits. The ground magnetic measurements were performed over an area of 6 750 m2 using a high-resolution Proton Precession Magnetometer G-19 Geometric. Total magnetic field data were acquired as a 3-m grid station along survey lines spaced 3-m apart. Total magnetic field anomalies were calculated by diurnal and International Geomagnetic Reference Field corrections. To clarify the position of objects causing the anomalies, analytical signals and tilt derivative filters have been applied to the total magnetic field anomalies. The method found several structures with contrasting physical properties to those of the surrounding material. Both filters were able to identify the presence of circular, elongated, and square anomalies around the Indrapatra site. The archaeological interpretation of such structures is in terms of wells, canals, and road floors. The structures are made of limestone boulders buried within the uppermost sand layer. The burning process to cement the boulders causes their magnetic properties to be different in contrast to the layer of sand that covers them. Based on magnetic interpretation, three geoelectrical profiles were measured crossing the targeted objects using Supersting R8/IP 56 Electrode Electric Resistivity. Wenner configuration with 1-meter electrodes spacing was applied for a better model resolution. The inverted models of apparent resistivity data show an agreement with magnetic interpretation at shallow depth. The models also imaged the depth and geometry of the objects based on the electrical resistivity properties of subsurface materials. It is expected that the structures preserved tsunamigenic deposits, so the discovery of the structures will be able to contribute to further research on paleotsunami in Aceh.
      PubDate: 2022-11-07
       
  • Impact of road embankment construction on groundwater system in alluvial
           aquifers

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      Abstract: Abstract This study aims to evaluate the impact of road embankment construction on the groundwater system in alluvial aquifers that have excessively used groundwater. A road embankment was constructed across extensive flat alluvial deposits. Laboratory permeability tests demonstrated that the loading by road embankment significantly reduced the permeability of alluvial sediments, creating an impermeable boundary in the groundwater system. The numerical modeling results showed that road embankment acting as an impermeable boundary caused groundwater levels to rise in the upstream area but decline in the downstream area. However, unlike in other upstream areas, there was no noticeable rise in the groundwater level after the embankment construction in the area where the groundwater was in extensive use. The long-term water level monitoring also confirmed no meaningful change in water level during the road embankment construction. This is because the additional decline of the water level due to the decrease in the influence radius of groundwater pumping by the impermeable boundary offsets the increase in the upstream water level. The flow modeling and the water level monitoring showed that the overall impact of the road embankment construction on the groundwater supplies could be insignificant. However, the numerical modeling indicates that the degree of impact varies with the distance from the road embankment. This study implies that the impact of the road embankment construction on the groundwater supplies in the upstream area will depend on the geological and hydraulic settings, which determine the radius of influence, such as the hydraulic property of the alluvial aquifer, pumping rate, the number and location of pumps, etc.
      PubDate: 2022-11-02
       
  • Study on pore evolution characteristics of gas adsorption and desorption
           in coal under the action of liquid nitrogen

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      Abstract: Abstract CBM (Coalbed methane) belongs to unconventional natural gas mineral resources. The development and utilization of CBM can greatly reduce the occurrence of mine gas accidents, and how to improve the desorption capacity of CBM has always been a hot issue for researchers. Liquid nitrogen has obvious effect on coal seam cracking and permeability improvement. The purpose of this paper is to study the cracking mechanism of liquid nitrogen on coal, and provide a theoretical basis for using liquid nitrogen freezing and thawing to treat coal so as to improve the production of coalbed methane. Coal samples from Yangquan County, Shanxi Province were pretreated. The pore structure test, microscopic observation test and methane isothermal adsorption test were carried out after the coal samples with different particle sizes were treated with different liquid nitrogen freeze-thaw cycles. According to the experimental data, the evolution law of pores of coal before and after freezing and thawing with liquid nitrogen, the cracking mechanism of coal treated with freezing and thawing with liquid nitrogen, and the optimal number of freezing and thawing cycles with liquid nitrogen are analyzed. The results show that: 1) the evolution characteristics of pore structure of lower coal after liquid nitrogen freezing and thawing are that micropores in coal are promoted to develop into transition pores and mesopores, and mesopores and transition pores develop into macropores and fractures. 2) Through the observation of a metallographic microscope, the expansion degree of coal surface crack is positively correlated with the times of liquid nitrogen freeze-thaw. 3) Liquid nitrogen freeze-thaw treatment has an optimal number of cycles for the cracking degree of coal. With the increase of freeze-thaw cycles, the final adsorption capacity of coal pillar increases first and then decreases; The adsorption capacity of granular coal first increases and then decreases. After reaching freeze-thaw saturation, continued freeze-thaw is not conducive to the increase of adsorption capacity. These research results provide theoretical support for the implementation of liquid nitrogen fracturing and permeability enhancement technology in coal reservoirs.
      PubDate: 2022-11-02
       
  • Controls on sediment storage in wide mountain valleys — a case study
           from Srinagar (Garhwal) valley, NW Himalaya

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      Abstract: Abstract The valley-fill deposits in a tectonically active setting play a key role in understanding a river’s response to climatic/tectonic shifts. These deposits are a result of the interaction between the regional and the local processes, which in turn are controlled by tectonics and climate. In this study, valley-fill deposits in the widest reach of the Alaknanda River (a headwater tributary of the Ganga River)—the Srinagar valley—in the northwest Himalaya is investigated for the interaction between, 1) the axial channel (representing regional processes) and local tributary (representing local processes) and 2) axial channel and hillslope (representing local processes). We identified eight levels of terraces and five levels of debris flow surfaces in the Srinagar valley. The terraces are composed of axial river deposits and local stream deposits, whereas debris flow surfaces mainly consist of hillslope deposits. Strath terraces are also present towards the western part of the valley. The 1D resistivity survey and field data show that thick sedimentary cover caps the bedrock in the eastern part of the Srinagar valley. Geochronology data based on optically stimulated luminescence (OSL) dating suggests that some of the sediments in the Alaknanda valley are older than 80 ± 5 ka. Integration of results shows that the width of the Srinagar valley is controlled structurally by the presence of the North Almora Thrust (NAT), a regional structure present in the Alaknanda River basin. The valley width increases around the central part of the Srinagar valley; this increase in width has provided accommodation space and resulted in thick sedimentation. Major filling and evacuation of the Srinagar valley occurred between 80 ± 5 ka and 8 ± 1 ka. The study demonstrates that the long-term interaction of the axial river, tributaries, and the hillslope processes can often be masked by the younger sediments to give a deceptive morphology and evolution history, if not thoroughly investigated.
      PubDate: 2022-11-02
       
  • Measurement of surface deformation related to the December 2018 Mt. Etna
           eruption using time-series interferometry and magma modeling for hazard
           zone mapping

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      Abstract: Abstract Mount Etna has erupted several times since it was first formed. Recently, Mount Etna began erupting again over 24–27 December 2018. Because it erupts frequently, Mount Etna should be observed on a frequent basis. From June 2018 to October 2019, 34 and 56 synthetic aperture radar (SAR) images were acquired from the ascending and descending tracks of the Sentinel-1 satellite, respectively. We employed the Stanford Method for Persistent Scatterers (StaMPS) and a refined small baseline subset (SBAS) InSAR method to produce a surface deformation time-series map. In the time-series analysis, the phase signal remained unaltered with time. The Okada model was then applied to the result to generate a modeled interferogram, and the Q-LavHA program was run to generate a lava flow prediction model. A direct comparison of the results showed that Persistent Scatterers Interferometry (PSI)-StaMPS and the refined SBAS technique were comparable in terms of the displacement pattern, with slightly different velocity values obtained for individual points. In particular, a velocity range of −25 to 21 cm/yr was obtained from PSI-StaMPS, whereas a range of −30 to 25 cm/yr was obtained from the refined SBAS method. Upon computation of the vertical and east-west displacement components based on ascending and descending track data using both methods, deformation velocities of 51.5 and 52.5 cm/yr in the westerly direction on the western flank of Mount Etna were obtained from PSI-StaMPS and the refined SBAS method, respectively, whereas on the eastern flank, deformation toward the east was estimated to occur at a velocity of 50.1 or 54.2 cm/yr, respectively. PSI-StaMPS estimated a vertical deformation velocity of −5.3 to 18.3 cm/yr, whereas the refined SBAS method produced a velocity range of approximately −7 to 19 cm/yr. The interferogram obtained via Okada modeling showed two fault sources in the 2018 Mount Etna eruption and a total volume change of approximately 12.39 × 106 m3. From the modeling results, a lava flow prediction model was generated using the Q-LavHA program. The approaches described in this study can be used by government officials, authorities, and other decision-makers to monitor and assess the risk of volcanic activity in the region.
      PubDate: 2022-10-17
       
  • Improvement of fluid penetration in soil by plasma blasting

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      Abstract: Abstract Plasma blasting by high-voltage arc discharge was performed in laboratory-scale soil samples to investigate fluid penetration. A plasma blasting device with a large-capacity capacitor and columnar soil samples with a diameter of 80 cm and a height of 60 cm were prepared. The columnar soil samples were made of sand and silt mixed in a 7:3 ratio (the A samples) or a 9:1 ratio (the B samples). When fluid was injected by pressure without plasma blasting, fluid penetrated into the soil only near the borehole, and the penetration area ratio was less than 10%. In further tests, fluid was injected by plasma blasting with different discharge energies of 1–27 kJ. When plasma blasting was performed once in the A samples, the penetration area ratios of the fluid were 16–25%; after five consecutive blasts, the penetration area ratios were 30–48%. When five consecutive plasma blasts were carried out on the B samples, the fluid penetration area ratios were 33–72%. This difference indicates that the fluid penetration area increases with higher discharge energy of plasma blasting and with a greater number of blasts. The fluid penetration radius was calculated to assess the fluid penetration volume. When the fluid was injected by hydraulic pressure only, the penetration radius was 9–12.4 cm, whereas the penetration radius was 27–33.2 cm when blasting was performed five times. The radius was increased by up to 200% by plasma blasting. In the field tests, the fluid injection in the test hole subjected to plasma blasting was greater by about 170% compared with the control test hole, in which the fluid was injected only by hydraulic pressure. In addition, the electrical resistivity around the test hole subjected to plasma blasting was markedly lower, and fluid diffused from this test hole to a minimum radius of 2 m. These results indicate that a cleaning agent will penetrate further and the remediation efficiency of contaminated soil will be improved if plasma blasting is applied for in situ cleaning of low-permeability contaminated soil.
      PubDate: 2022-10-11
       
  • Geochemical signatures of organic matter associated with gas generation in
           the Pohang Basin, South Korea

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      Abstract: Abstract We investigated the source, maturity, and biodegradation of organic matter (OM) deposited at two core sites (PSG-02 and PSG-03) of the Pohang Basin by analyzing stable isotopic compositions of bulk organic matter and specific lipid molecules (n-alkanes). In contrast to the lack of substantial variations in bulk carbon isotopic compositions along core depths, a homologous series of saturated alkanes (C16 to C35) showed distinct carbon chain-length distribution between both core sites, having predominance in C20 to C25 for PSG-02 and C29 for PSG-03. Such variation may reflect the different geochemical properties of the deposited OM involved in gas generation. In this regard, various n-alkane indices, for example, carbon preference index (CPI), terrestrial/aquatic ratio (TAR), average chain length (ACL), natural n-alkanes ratio (NAR), percentage of aquatic plants (Pmar-aq), and pristane/phytane (Pr/Ph), were applied to understand the OM origins and depositional environments at both core sites. The contribution of thermally petroleum-derived OM is predominant in PSG-02, as shown by the low values of CPI (< 1) and NAR (< 0.6). Conversely, high values of ACL (> 29), TAR (> 2), low values of Pmar-aq (< 0.4) and Pr/Ph (∼1) may be associated with mixed contributions of marine and terrestrial OM sources in PSG-03. In addition, Pr/Ph ratios suggest that sedimentary diagenesis conditions such as maturity and redox condition should be different between both core sites. Our results highlight useful information regarding the geochemical properties of OM involved in gas generation in the Pohang Basin. This will help us better define accumulated gas systems and reduce the risk associated with future exploration efforts in this area.
      PubDate: 2022-10-01
      DOI: 10.1007/s12303-021-0046-y
       
  • Confirmation of the Floian-Darriwilian (Lower to Middle Ordovician) hiatus
           in the Taebaek Group, Korea: integration of conodont biostratigraphy and
           sedimentology

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      Abstract: Abstract An Ordovician depositional hiatus spanning the middle Floian to lower Darriwilian, estimated to represent a period of at least 3 Myr, is confirmed for the first time in the Taebaek Group, Korea, based on integrated conodont biostratigraphic and sedimentologic data. The conodont biozones of the uppermost Dumugol and lower Makgol formations are revised and redefined with presentation of a new biozonal framework, which contains, the Serratognathus bilobatus Biozone, the Serratognathus extensus Biozone, the Paraserratognathus obesus Biozone, and the Tangshanodus tangshanensis Biozone in ascending order. The hiatus lies within the barren interval between the middle Floian Paraserratognathus obesus Biozone and the early Darriwilian Tangshanodus tangshanensis Biozone. The unconformity surface is located at the boundary between the basal and lower members of the Makgol Formation, 1.5 meters above the base of the barren interval, on the basis of sedimentary evidence such as differences in the depositional and diagenetic features as well as a sharp contact between the two members with subaerial exposure feature including vuggy to channel pore and dolostone breccia. The barren interval above the hiatus is considered due to environmental factor: the peritidal condition is regarded unfavorable for inhabitation of conodont animals. The newly established Floian and Darriwilian conodont biozones and depositional hiatus within the lower Makgol Formation indicate that the Ordovician succession of the Taebaek Group is essentially an extension of that of the North China Block.
      PubDate: 2022-09-07
      DOI: 10.1007/s12303-022-0018-x
       
  • Crack initiation and propagation thresholds of Hwangdeung granite under
           elevated temperature

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      Abstract: Abstract In this study, we investigated the effect of high temperature on the mechanical behavior of Hwangdeung granite in Korea. Uniaxial compression and Brazilian tests were performed under temperatures ranging from 20 °C to 250 °C. The development of the thermally induced microcracks was observed utilizing a scanning electron microscope (SEM). The target temperature was chosen for rock engineering projects, such as high-level radioactive waste disposal, enhanced geothermal energy, and thermal energy storage. Considering the long-term strength and fracture process associated with crack development, we examined the temperature dependence of crack initiation and propagation thresholds and conventional strength and deformation parameters, as well as the stress-strain relation under high temperature. Compressive strength, tensile strength, and Young’s modulus decreased with increasing temperature, particularly at temperatures above 100 °C, and Poisson’s ratio decreased linearly. The changes in the tensile strength and elastic constants were more pronounced than those in uniaxial compressive strength. The stress-strain curves revealed that the thermal effect on deformation, rather than strength, was evident. Microscopic observations of the heated rock samples have revealed that high temperature promoted the interaction and networking of pre-existing and thermally induced cracks, resulting in microstructural damage before loading. We determined the crack closure stress, crack initiation stress, and crack damage stress under the respective temperatures by analyzing the stress-strain curves. An increase in temperature increased the crack closure stress and reduced the crack initiation stress, resulting in a decreased elastic range; the former increased by 12.1 MPa as the temperature increased from 20 °C to 250 °C, and the latter significantly reduced by 25.1 MPa. This finding suggests that the mechanical behavior of rocks or rock masses under high-temperature conditions, particularly at low-stress levels, is uncertain and cannot be approximated with standard material properties. No systemic relation was detected between temperature and crack damage stress; however, the volumetric strain at the crack damage stress increased consistently with temperature.
      PubDate: 2022-08-13
      DOI: 10.1007/s12303-022-0015-0
       
  • Seismological characteristics of microearthquake sequence near Suncheon,
           South Korea, from 2009 to 2020

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      Abstract: Abstract We analyzed the seismological characteristics of a microearthquake sequence that occurred from September 2009 to August 2020 with epicenters concentrated within a small area, ∼10 km WNW of downtown Suncheon, South Korea. During the study period, 33 events with a local magnitude (ML) < 2.0 were cataloged by the Korea Meteorological Administration. We identified 101 uncataloged events in the source region by using the matched filter method and estimated magnitudes based on amplitude ratios measured with a reference event. The focal mechanism solutions of 16 events were obtained with P-wave polarities and S-wave to P-wave amplitude ratios, which were used in iterative stress inversion to estimate the current stress orientation. The hypocenters of this sequence were relocated using the double-difference method. A total of 133 relocated microearthquakes were aligned at ∼11 km depth along a 500 m long lineation with an azimuth of N80°E and a dip of 84°N. This matched very well with the principal focal mechanism from the stress inversion of 16 focal mechanism solutions, striking N77°E with a dip of 88°N. The maximum principal stress direction of the Suncheon microearthquake sequence was a trend of NE-SW, slightly different from the regional tectonic stress in the eastern Eurasian plate, which may imply the existence of local stress perturbations in the study area.
      PubDate: 2022-07-14
      DOI: 10.1007/s12303-022-0010-5
       
  • Outcrop modeling of flow units and reductant within a sandstone uranium
           reservoir in the Zhiluo Formation, eastern Ordos Basin: implications for
           the uranium mineralization mechanism

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      Abstract: Abstract The spatial distribution of flow units and reductant within a sandstone uranium reservoir is very beneficial for exploring the uranium mineralization mechanism; however, such studies have been almost neglected. As such, this paper aims to provide the sedimentological interpretation and heterogeneity models of the sandstone of the Middle Jurassic Zhiluo Formation at Shiwan outcrop area, in the eastern Ordos Basin. The outcrops are sandstone-dominated subaqueous distributary channel successions, in which five distinct architectural elements are identified and interpreted: channel units (CU), downstream accretion elements (DA), lateral accretion elements (LA), sandy bedforms (SB) and no-channelized fine-grained sediments (NFS). Within the sandstone succession, six flow units are present in the middle and lower parts of CU, or the lower parts of DA and SB elements, with their geometry to be controlled by the fourth- or third-order bounding surfaces. Moreover, the carbonaceous debris-rich zones (CDZ) are places with the highest abundance of reductant and preserve exclusively upon the basal erosional surfaces of CU and DA elements. Based on those results, a prediction model is established and shows that the formation of interlayer oxidation zone is strongly selective and confined within the CU and DA elements. The favorable site of uranium mineralization is preferentially distributed in the transition zone between the front of flow unit and the CDZ.
      PubDate: 2022-06-27
      DOI: 10.1007/s12303-022-0008-z
       
  • An optimal strategy for determining triple oxygen isotope ratios in
           natural water using a commercial cavity ring-down spectrometer

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      Abstract: Abstract Triple oxygen isotope ratios have been increasingly acknowledged as useful hydrological tracers but measuring both 17O/16O and 18O/16O ratios with meaningful precision has been challenging due to the much lower natural abundance of 17O than 16O and even 18O. In this study, in line with the advancement of laser-based techniques and their growing applications, we demonstrate how to optimize the determination of 17O-excess (Δ17O = ln(δ17O + 1) − 0.528 × ln(δ18O + 1)) in natural water using a commercial wavelength-scanned cavity ring-down spectrometer (WS-CRDS). We particularly focus on how to decide the injection numbers of samples and standard solutions utilized for normalization of sample results to the VSMOW-SLAP reference scale. With a measurement strategy aimed at an uncertainty better than 10 per meg (1σ), the Δ17O of Greenland Ice Sheet Precipitation (GISP) is determined to be 24 ± 9 per meg (n = 104), in agreement with previous literature values. By applying this method to Antarctic glacial ice, it is shown to be useful in detecting the seasonality of Δ17O values in Antarctic precipitation. Our approach represents an underlying analytical method that provides guidelines for determining Δ17O from various types of natural waters.
      PubDate: 2022-06-27
      DOI: 10.1007/s12303-022-0009-y
       
  • The Jangsan Formation refined

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      Abstract: Abstract Formation comprises a distinctive set of sedimentary layers, which can be traceable laterally and mapped as a unit. It is a fundamental unit for stratigraphic position in a regional scale and provides an important basis for the interpretation of depositional processes and environments. This paper reviews the occurrence of the Jangsan Formation at the base of the Taebaek Group (Cambrian-Ordovician) in the Taebaeksan Basin and refines the geologic map unit for sedimentary characteristics and stratigraphic position. The refined Jangsan Formation comprises a set of distinctive sandstone (quartzite) with a number of sedimentary facies, including conglomerate, conglomeratic sandstone, and mudstone. The “Myeonsan Formation” is limited to a localized set, and leads it fallen into disuse. The refined Jangsan Formation can be reliably correlated with the equivalent early Cambrian sandstone unit (Liguan Formation) in Shandong Province, China about a thousand kilometers apart and elsewhere in the northeast Asian continent.
      PubDate: 2022-06-09
      DOI: 10.1007/s12303-022-0006-1
       
 
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