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EARTH SCIENCES (527 journals)            First | 1 2 3     

Showing 401 - 371 of 371 Journals sorted alphabetically
Physical Geography     Hybrid Journal   (Followers: 8)
Physical Science International Journal     Open Access  
Physics in Medicine & Biology     Full-text available via subscription   (Followers: 15)
Physics of Life Reviews     Hybrid Journal   (Followers: 1)
Physics of Metals and Metallography     Hybrid Journal   (Followers: 18)
Physics of Plasmas     Hybrid Journal   (Followers: 10)
Physics of the Earth and Planetary Interiors     Hybrid Journal   (Followers: 34)
Physics of the Solid State     Hybrid Journal   (Followers: 6)
Physics of Wave Phenomena     Hybrid Journal  
Physics World     Full-text available via subscription   (Followers: 18)
Physik in unserer Zeit     Hybrid Journal   (Followers: 9)
Pirineos     Open Access  
Planet     Open Access   (Followers: 4)
Plasma Physics and Controlled Fusion     Hybrid Journal   (Followers: 6)
Plasma Physics Reports     Hybrid Journal   (Followers: 7)
Polar Record     Hybrid Journal   (Followers: 2)
Positioning     Open Access   (Followers: 4)
Pramana     Open Access   (Followers: 13)
Precambrian Research     Hybrid Journal   (Followers: 7)
Preview     Hybrid Journal  
Proceedings of the Geologists' Association     Full-text available via subscription   (Followers: 6)
Proceedings of the Linnean Society of New South Wales     Full-text available via subscription   (Followers: 2)
Proceedings of the Yorkshire Geological Society     Hybrid Journal   (Followers: 1)
Progress in Earth and Planetary Science     Open Access   (Followers: 16)
Pure and Applied Geophysics     Hybrid Journal   (Followers: 12)
Quarterly Journal of Engineering Geology and Hydrogeology     Hybrid Journal   (Followers: 4)
Quaternary     Open Access  
Quaternary Australasia     Full-text available via subscription  
Quaternary Geochronology     Hybrid Journal   (Followers: 8)
Quaternary International     Hybrid Journal   (Followers: 14)
Quaternary Research     Full-text available via subscription   (Followers: 19)
Quaternary Science Advances     Open Access  
Quaternary Science Reviews     Hybrid Journal   (Followers: 26)
Radiocarbon     Hybrid Journal   (Followers: 12)
Remote Sensing     Open Access   (Followers: 57)
Remote Sensing Applications : Society and Environment     Full-text available via subscription   (Followers: 9)
Remote Sensing in Earth Systems Sciences     Hybrid Journal   (Followers: 5)
Remote Sensing Letters     Hybrid Journal   (Followers: 45)
Remote Sensing Science     Open Access   (Followers: 29)
Rendiconti Lincei     Hybrid Journal  
Reports on Geodesy and Geoinformatics     Open Access   (Followers: 8)
Reports on Mathematical Physics     Full-text available via subscription   (Followers: 2)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 18)
Resource Geology     Hybrid Journal   (Followers: 6)
Resources, Environment and Sustainability     Open Access   (Followers: 1)
Results in Geochemistry     Open Access  
Results in Geophysical Sciences     Open Access  
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 4)
Reviews of Modern Physics     Full-text available via subscription   (Followers: 31)
Revista Cerrados     Open Access  
Revista de Ciências Exatas Aplicadas e Tecnológicas da Universidade de Passo Fundo : CIATEC-UPF     Open Access  
Revista de Ingenieria Sismica     Open Access  
Revista de Investigaciones en Energía, Medio Ambiente y Tecnología     Open Access  
Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales     Open Access  
Revista de Teledetección     Open Access  
Revista Geológica de Chile     Open Access  
Revue Française de Géotechnique     Hybrid Journal  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 7)
Rocks & Minerals     Hybrid Journal   (Followers: 3)
Russian Geology and Geophysics     Hybrid Journal   (Followers: 2)
Russian Journal of Mathematical Physics     Full-text available via subscription  
Russian Journal of Pacific Geology     Hybrid Journal  
Russian Physics Journal     Hybrid Journal   (Followers: 1)
Science China Earth Sciences     Hybrid Journal   (Followers: 3)
Science News     Hybrid Journal   (Followers: 11)
Science of Remote Sensing     Open Access   (Followers: 7)
Scientific Annals of Stefan cel Mare University of Suceava. Geography Series     Open Access  
Scientific Journal of Earth Science     Open Access   (Followers: 1)
Scientific Reports     Open Access   (Followers: 85)
Sedimentary Geology     Hybrid Journal   (Followers: 20)
Sedimentology     Hybrid Journal   (Followers: 15)
Seismic Instruments     Hybrid Journal   (Followers: 1)
Seismological Research Letters     Full-text available via subscription   (Followers: 12)
Soil Dynamics and Earthquake Engineering     Hybrid Journal   (Followers: 14)
Soil Security     Open Access   (Followers: 3)
Solid Earth     Open Access   (Followers: 5)
Solid Earth Discussions     Open Access   (Followers: 1)
Solid Earth Sciences     Open Access   (Followers: 1)
South African Journal of Geomatics     Open Access   (Followers: 2)
Standort - Zeitschrift für angewandte Geographie     Hybrid Journal   (Followers: 2)
Stratigraphy and Geological Correlation     Full-text available via subscription   (Followers: 2)
Studia Geophysica et Geodaetica     Hybrid Journal   (Followers: 1)
Studia Geotechnica et Mechanica     Open Access  
Studia Universitatis Babes-Bolyai, Geologia     Open Access  
Survey Review     Hybrid Journal   (Followers: 6)
Surveys in Geophysics     Hybrid Journal   (Followers: 3)
Swiss Journal of Palaeontology     Hybrid Journal   (Followers: 4)
Tectonics     Full-text available via subscription   (Followers: 15)
Tectonophysics     Hybrid Journal   (Followers: 24)
Tellus A     Open Access   (Followers: 21)
Tellus B     Open Access   (Followers: 20)
Terra Latinoamericana     Open Access  
Terra Nova     Hybrid Journal   (Followers: 5)
The Compass : Earth Science Journal of Sigma Gamma Epsilon     Open Access  
The Holocene     Hybrid Journal   (Followers: 16)
The Leading Edge     Hybrid Journal   (Followers: 1)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Turkish Journal of Earth Sciences     Open Access  
UD y la Geomática     Open Access  
Unconventional Resources     Open Access  
Underwater Technology: The International Journal of the Society for Underwater     Full-text available via subscription   (Followers: 1)
Universal Journal of Geoscience     Open Access  
Unoesc & Ciência - ACET     Open Access  
Vadose Zone Journal     Open Access   (Followers: 5)
Volcanica     Open Access  
Water     Open Access   (Followers: 10)
Water International     Hybrid Journal   (Followers: 19)
Water Resources     Hybrid Journal   (Followers: 21)
Water Resources Research     Full-text available via subscription   (Followers: 94)
Watershed Ecology and the Environment     Open Access  
Weather, Climate, and Society     Hybrid Journal   (Followers: 15)
Wiley Interdisciplinary Reviews - Climate Change     Hybrid Journal   (Followers: 33)
World Environment     Open Access   (Followers: 1)
Yearbook of the Association of Pacific Coast Geographers     Full-text available via subscription   (Followers: 2)
Yugra State University Bulletin     Open Access   (Followers: 1)
Zeitschrift der Deutschen Gesellschaft für Geowissenschaften     Full-text available via subscription   (Followers: 3)
Zeitschrift für Geomorphologie     Full-text available via subscription   (Followers: 5)
Zitteliana     Open Access  
Землеустрій, кадастр і моніторинг земель     Open Access   (Followers: 1)

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Russian Journal of Pacific Geology
Journal Prestige (SJR): 0.374
Citation Impact (citeScore): 1
Number of Followers: 0  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1819-7159 - ISSN (Online) 1819-7140
Published by Springer-Verlag Homepage  [2469 journals]
  • The Khanka Massif: The Heterogeneity of its Basement and Regional
           Correlations

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      Abstract: Abstract This paper reports new geochronological data on metagranitoids (U–Pb SIMS) and ophiolites (Sm–Nd) from the Khanka massif. New and published data define the Early Neoproterozoic Matveevka–Nakhimovka terrane with 935- and 915-Ma early suprasubduction magmatism, 850–880-Ma and 757-Ma withinplate and Pacific-type transform margin magmatism, as well as the Late Neoproterozoic–Early Cambrian Dvoryan and Tafuin terranes with 543, 520, 517, and 513-Ma suprasubduction magmatism. These two terranes are separated by a suture (Voznesenka and Spassk terranes) formed by Ediacaran–Cambrian shelf deposits and a Cambrian accretionary wedge with ophiolites older than 514 Ma. The greater part of the Khanka massif formed in the late Cambrian, with the Kordonka island-arc terrane accreted at the end of the Silurian. The Sergeevka terrane of the Ordovician island arc joined it through the Early Cretaceous strike-slip movements. Heterogeneous structures of the main part of the Khanka massif can be traced to the north based on the analogous stages of magmatism and metamorphism, where the Jiamusi massif (including the East Bureya terrane) is an Early Neoproterozoic block and the eastern Songnen massif (including the West Bureya terrane) is a Late Neoproterozoic–Cambrian block. These blocks are separated by the Spassk–Wuxingzhen–Melgin suture formed by their collision in the Late Cambrian. The Bureya–Songnen–Jiamusi–Khanka superterrane formed as a part of the Gondwana supercontinent approximately 500 Ma ago through orogeny and accretion of the Rodinia supercontinent fragments.
      PubDate: 2022-08-01
       
  • The Eocene–Oligocene Boundary in the Cenozoic Complex in the Primorye
           Region (Far Eastern Russia)

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      Abstract: Upper Eocene–Lower Oligocene sections in the Primorye region were analyzed to choose the most promising one to mark the Eocene–Oligocene boundary. We proposed that the boundary between the Khasan and Fatashinskaya formations in the Cenozoic Complex of the Khasan depression is its stratotype. Zircon radioisotope datings confirm the inferences on the age of the formations derived from paleobotanical data. The age of the lower strata of the Khasan Formation is estimated at 38 Ma in the stratotype (Posyet Peninsula) and 37 Ma in the hypostratotype (in the northern part of the depression). The age of the Fatashinskaya Formation base is constrained by the Kraskino flora with its complex of taxa in the narrow stratigraphic range. Analogs of this fossil flora are known to be found in the adjacent and distant areas. According to the radioisotope data, the age of the corresponding deposits correlates with the time interval of 31.4–33.6 Ma.
      PubDate: 2022-08-01
       
  • Geodynamic Analysis and a Regional-Scale Forecast of the Hydrocarbon
           Exploration Potential of the Tatar Strait, Sea of Japan Using Numerical
           Modeling Technologies

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      Abstract: This paper presents the results of analysis and numerical modeling of the sedimentary basins of the riftogenic trough of the Tatar Strait, the Sea of Japan, which allowed the creation of its 3D structural model and determination of the conditions for the formation of its generation-accumulation hydrocarbon systems. To study the geodynamic evolution of the sedimentary basins in the Tatar Strait, the digital reconstruction of the history of subsidence and sedimentation was performed using the numerical basin modeling technologies. The chronothermobaric conditions of the occurrence and evolution of the sources of hydrocarbon generation and the formation of oil and gas accumulations in the sedimentary basins of the riftogenic trough were reconstructed by 3D modeling of the generation–accumulation hydrocarbon systems using PetroMod software (Schlumberger, Ltd., United States). Modeling of the hydrocarbon systems revealed the fundamental features of their structure in the Tatar Strait water area at the modern stage of their development, which are generally as follows: the sources of hydrocarbon generation are located in the depressions of the sedimentary basins, the rock maturity decreases from south to north with their occurrence depths, and hydrocarbons accumulate along the marginal zones of the basins.
      PubDate: 2022-08-01
       
  • The Petrophysical Characteristics of Tectonic Structures in the Western
           Okhotsk Region

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      Abstract: Abstract The physical properties of rocks from the western Okhotsk region were studied and petrophysical maps were constructed to highlight the petrophysical features of tectonic elements of the territory. Petrophysical heterogeneities and anomalies of the respective geophysical fields were compared. The relationship between magnetic anomalies and subsurface rock complexes has been established only for the Mesozoic volcano-plutonic structures of the Okhotsk-Chukotka volcanic belt and partly for the Yudoma–Maya lithotectonic zone. In the ancient blocks of the Aldan–Stanovoy shield and the Uchur–Maya plate, the magnetic anomalies are mainly associated with activation of tectonic–magmatic processes and, to a lesser extent, with the magnetic properties of definite rocks. Inverse relationships have been established between the gravity anomalies and rock density anomalies within the regional gravity low (Tyrkan and South-Verkhoyansk gravity fields) and in the Vilyui syneclise, where gravity high corresponds to the low-density domains.
      PubDate: 2022-08-01
       
  • Taking a Fresh Look at the Stratigraphy of the Selemdzha and Tokur
           Terranes of the Mongol–Okhotsk Belt: The Results of U–Pb, Lu–Hf, and
           Sm–Nd Isotope Studies

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      Abstract: Abstract The results from U–Pb, Lu–Hf, and Sm–Nd isotope studies of metasedimentary rocks from the Selemdzha and Tokur terranes of the Mongol–Okhotsk belt contradict the existing concepts on the stratigraphy of the region and indicate the need to revise the traditional principles of mapping within the belt. Two types of deposits that sharply differ in their Sm–Nd whole-rock characteristics and Lu–Hf isotope compositions of detrital zircons have been established within the terranes. Deposits of different types are involved in the formation of the two opposite accretionary systems: in front of the Siberian Craton margin (type I) and the Amur superterrane (type II). The type I deposits are divided into groups with different lower age limits: 553–498 Ma, Late Ediacaran–Cambrian; ~373 Ma, Upper Devonian; 333–327 Ma, Upper Mississippian; and ~304 Ma, Pennsylvanian. The deposits of the tectonic-stratigraphic units show a general trend of decreasing age from north southward. The same trend is observed from the upper to lower sheets. Such a structure is typical of accretionary wedge-shaped terranes with a rear part in the north and a frontal part in the south. The tectonic-stratigraphic units formed by type I deposits and previously ascribed to the Selemdzha and Tokur terranes likely belong to the Galam accretionary wedge terrane.
      PubDate: 2022-08-01
       
  • The Role of Metamorphic Devolatilization in Building Orogenic Gold
           Deposits within Paleoproterozoic Organic-Rich Sediments: P-T-X
           Thermobarometric and Carbon Isotopic Constraints from the Chertovo Koryto
           Deposit (Eastern Siberia)

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      Abstract: Orogenic gold deposits hosted by terrigenous sediments rich in organic matter as well as the role of host sediments and their metamorphic modification in making up such deposits remain highly debatable. So far, the origin of gold deposits in the Lena gold province (Eastern Siberia) mainly hosted by folded and deformed Neoproterozoic complexes of passive-margin sediments, including the giant Sukhoi Log teposit, has been regarded to as postmagmatic (juvenile) or metamorphic, primarily driven by metamorphic devolatilization and redistribution of metals with carbon-rich fluids. Yet, the origin of similar but smaller-scale deposits hosted by the underlying Paleoproterozoic metasediments in the same area is poorly known. The aim of this work was to establish the key processes, which contributed to the formation of gold and associated mineralization of the Chertovo Koryto deposit, through fluid inclusion thermobarometry, spectroscopy and carbon isotopic composition. Fluid inclusions in different types of quartz from the deposit were studied by Raman spectroscopy and cryothermometry. The high P–T parameters (2.8 kbar; 440°C) indicate the initial stage of the ore process. The interaction of metamorphic water-rich fluid with organic matter of the host sediments led to oxidation of water with the release of CO2. The ore precipitation was associated with a sharp pressure decrease (0.3–0.6 kbar) and cooling of the system (320–200°C), which, according to the model, occurred as a result of tectonic deformations and open cavities within the zone of maximum tectonic stress. This pressure reduction zone was the most suitable for the deposition of gold-containing liquid. The overprinting ore-barren stage was characterized by even lower temperatures to (154–87°C) but a wider pressure range (0.1–0.6 kbar). Similar carbon isotopic composition of fluid inclusions in quartz from the early ore stage (δ13C within –16.9 to –17.8%) and the gold precipitation stage (from –16.6 to –17.9%) resembling that of the host Neoproterozoic sediments and previously reported isotopic data for other deposits (Sukhoi Log, Krasniy) suggest the uniform inheritance of metal-bearing C–N–H–S-rich fluid fluid from the host black-shale sediments. Overall, the results suggest that the whole process of sedimentary preconditioning to metamorphic redistribution of gold and other metals in carbon-rich fluids in the Chertovo Koryto deposit was governed primarily by host sediments without any contribution from postmagmatic fluid activity. The data obtained are consistent with the model of orogenic deposits of the Sukhoi Log type and point out the contemporaneous and similar ore-forming processes overprinting both Neoproterozoic and Paleoproterozoic strata.
      PubDate: 2022-08-01
       
  • The Geoelectric Section of the Lithosphere in the Central Southern Sikhote
           Alin Fold System along the Dalnerechensk–Nakhodka Bay Profile from MT
           Soundings

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      Abstract: Based on the results of magnetotelluric soundings carried out along the profile starting in the north of the Khanka Massif, running toward the Sikhote Alin Fold System (SAFS) and extending along the eastern boundary of the massif to the Sea of Japan coast, the geoelectric section of the lithosphere was constructed down to a depth of 150 km. Conductive zones within the crust and high-resistivity zones in the upper mantle have been distinguished. Differences in the geoelectric parameters of the crust of the Late Proterozoic–Paleozoic Khanka Massif and the Central zone of the Albian-Cenomanian SAFS have been established. The crust and upper mantle latitudinal zonality has been confirmed. The impact of the coastal effect on the behavior of the Wiese vectors has been investigated and their relationship with the conductive zones in the crust and faults have been demonstrated.
      PubDate: 2022-08-01
       
  • Application of the LURR Method for Studying Seismicity in the Southern
           Kuril Islands

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      Abstract: An approach is proposed for analysis of seismic sequences in the Southern Kuril Islands using the Load/Unload Response Ratio (LURR) method. For our calculations, the optimal parameters were chosen for a circular area, the center of which was the epicenter of the Shikotan earthquake of October 4, 1994. The calculations were also carried out for two more earthquakes of August 11, 1969, and March 24, 1978, which were the strongest in the past century. In all cases, anomalies of the LURR parameter have been detected several years before the earthquakes. To test the stability of the anomalies, several zones were investigated near the epicenters of the events tested. The anomalies were inferred to be unstable; that is, they could emerge at different times or disappear completely. The prediction efficiency was tested in the epicentral region of the Shikotan earthquake for the time period of 1965–2020. Six anomalies were recorded during that time, five of which preceded earthquakes with a magnitude of mb ≥ 6.5 that either occurred in close proximity to or fell within the calculated area. In addition, one false alarm was revealed and a missed target was detected.
      PubDate: 2022-06-01
      DOI: 10.1134/S1819714022030071
       
  • A Spatiotemporal Change in Deep Sources for Cenozoic Volcanic Rocks in the
           Eastern Koryak Highlands

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      Abstract: A spatiotemporal analysis of the trace-element ratios and Sr, Nd, and Pb isotopic composition of Cenozoic post-accretionary volcanic rocks in the eastern Koryak Highlands (Northeastern Russia) has been carried out. The Early Paleogene volcanic complex is shown to be represented by moderate-Ti aluminous tholeiites with elevated contents of high field strength elements (HFSE) (except for Ta and Nb), which makes them similar to E-MORBs. The low (La/Yb)n and high Zr/Nb (25–35) ratios indicate the contribution of a depleted MORB-type component. At the same time, the basalts have low Nb/Ta, Ce/Pb, and Nb/La ratios at a high K/Nb ratio, which indicates the presence of a subduction component in the source. The low Zr/Hf and (Dy/Yb)n ratios indicate melting of a garnet-free protolith. The second (Miocene) stage is represented by subalkaline basaltic flows and dacitic extrusions and dikes forming a bimodal series. The basalts are characterized by low concentrations of large ion lithophile elements (LILE), enrichment in HFSE, and a fractionated REE pattern, with (La/Yb)n ratios varying from typical E-MORB values to those of within-plate tholeiites. The Nb/Ta, Ce/Pb, La/Ta, and Hf/Th ratios are close to those of within-plate tholeiites. The (Dy/Yb)n and (La/Yb)pm–Ybpm relations indicate the formation of Miocene basalts through selective melting of garnet peridotite with varying garnet contents in the source. Dacitic dikes, compared to the effusive facies, differ in the calc-alkaline differentiation trends and absolute concentrations of some elements. Early Quaternary alkaline olivine basalts and basanites of the Navarin area have high HFSE, LILE, and REE contents and are compositionally close to within-plate volcanic rocks of oceanic islands and continental rifts. The data points of these rocks in the discriminant diagrams are confined to the field of the low-degree melting of a garnet-rich within-plate source. The initial Sr, Nd, and Pb isotopic ratios indicate the derivation of Cenozoic basaltic rocks in the eastern part of the Koryak Highlands from depleted deep-seated sources. The similarity of isotope ratios in the Miocene and Early Quaternary basalts testifies that the source mantle was isotopically homogenized by local convection.
      PubDate: 2022-06-01
      DOI: 10.1134/S1819714022030034
       
  • Age and Composition of Igneous Rocks from the Cenozoic Sedimentary Cover
           of the Sakhalin Shelf

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      Abstract: The K–Ar isotope age and petrological–geochemical data were obtained for the first time on igneous rocks from a core recovered from previously drilled wells on the Sakhalin shelf. Based on these data, the igneous rocks were compared to the rocks of the Anivskiy, Orlovskiy, Lamanonskiy, and Chekhovskiy volcanic complexes. The isotopic ages obtained on rocks from the Lesogorskiy Complex of hypabyssal small intrusions exposed on the western coast of Sakhalin Island allowed tighter constraints to be placed on the timing of its formation (8.9–16.2 Ma).
      PubDate: 2022-06-01
      DOI: 10.1134/S1819714022030046
       
  • Time Pulses of Cenozoic Explosive Phreatic Eruptions in Southwestern
           Primorye: Correlation of the Results of Isotopic and Phytostratigraphic
           Age Dating

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      Abstract: The Cenozoic tephroid deposits as products of explosive phreatic eruptions of maar volcanoes in the southwestern part of the Primorye region are studied. These deposits represent rhyolitic ash and pumice pyroclastic layers with a high terrigenous component, including tephroid pseudoconglomerates. Isotopic dating of tephroid layers has made it possible to identify two time pulses of explosive volcanism: 30–34 and 23–24 Mya. The first time pulse coincides with the beginning of the formation of marginal seas and continental coal basins. It corresponds to the most productive coal accumulation stage, accelerated wood waste burial and coalification, and the development of a high-temperature geothermal field, and it can be compared with the well-known catastrophic eruption of Mount St. Helens in the United States of America. The second time pulse of explosive volcanism is regional in nature. It is characterized by the formation of green tuff complexes on submarine elevations of the Sea of Japan as well as along the western and eastern coasts of Japan. The volcanic activity is accompanied by the accelerated sinking of the bottom of the Sea of Japan in response to the active rising of asthenospheric diapirs. The estimated isotopic ages do not conform to those determined for fossil leaves and pollen from the deposits likely due to the climate-forming type of this explosive process.
      PubDate: 2022-06-01
      DOI: 10.1134/S181971402203006X
       
  • Changes in the Mineral and Chemical Composition of Sills during their
           Intrusion Emplacement into the Sedimentary Cover, Guaymas Basin, Gulf of
           California (DSDP Holes 477, 477A, 478, 481/481A)

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      Abstract: In the Guaymas Basin of the Gulf of California, changes in the mineral and chemical composition of sills of different thicknesses were studied in hydrothermal systems, which originated during the intrusion of the hot sills into young (Pleistocene) cold seawater-saturated sediments. Holes DSDP 477 and 477A were drilled in a high heat flow area, and holes 478 and 481/481A, in a low heat flow area. Thick sills from holes 477, 477A, and 478 (47, 30, and 112 m, respectively) remained fresh or very weakly altered because water released from the host Pleistocene sediments upon heating practically did not penetrate them. Olivine (a few wt %) in the sills remains unaltered, whereas mesostasis also amounting to a few percent is replaced by clay minerals. The high heat flow alone, without water input, could not provide favorable conditions for the changes in the mineral and chemical composition of thick sills in holes 477 and 477A (1250 mW/m2). The thin (from 0.1 to 0.65 m thick) and relatively thin (from 1.2 to 4.5 m) sills recovered in holes 478 and 481/481A were altered. They are fractured and therefore favorable for the penetration of water released from heated host sediments. In addition, a large volume of these sills is occupied by mesostasis (mainly from 18 to 45%, reaching in some samples from 53 to 70%) variably replaced by clay minerals. Olivine is frequently completely replaced by clay minerals. The alteration of thin basalt sills is accompanied by a sharp decrease in the K content, which in some cases is accompanied by an insignificant decrease in Mn, Mg, P, Na, and Ti. The low heat flow measured in the areas of holes 478 and 481/481A (150 and 165 mW/m2) indicates that the established mineral and chemical changes in the thin sills were caused by auto-hydrothermal processes, without heat and mass impact of convective long-lived hydrothermal systems.
      PubDate: 2022-06-01
      DOI: 10.1134/S1819714022030058
       
  • Rock Magnetism and Paleomagnetism of Mafic Dykes of the Sergeevka Terrane
           (Southern Sikhote-Alin)

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      Abstract: The results of petromagnetic and paleomagnetic studies of rocks from mafic dykes of the Sergeevka Terrane that intruded the basement rocks and are widespread in coastal outcrops of the eastern part of Peter the Great Bay of the Sea of Japan between the Anna and Priboinaya bays in the southern part of Primorskii krai are reported. The structural information allows us to conclude that dykes of both the eastern (Srednyaya Bay–Priboinaya Bay) and western (Anna Bay–Cape De Livron) clusters intruded from the igneous feeding channels of the same orientation. Rocks of the dykes were subjected to significant secondary alterations. Inverse magnetic fabric in the dykes is due to high-temperature decomposition and granulation of primary titanomagnetites upon postmagmatic deformations and metamorphism, traces of which are clearly visible in the microscopic and microprobe study of secondary alteration products. This provides evidence for a significant secondary change in rocks of the dykes after their intrusion. This is the secondary heating of the dykes above the temperature of 600°C, i.e., above the Curie point of magnetite (578°C). The nature of the isolated high-temperature NRM component of the dykes is not primary, but secondary, that is, metachronous. The paleomagnetic data constrained the time of the metamorphic event leading to the remagnetization of mafic dykes of the Sergeevka Terrane to about 250 Ma. The calculated paleolatitude of the Sergeevka Terrane at the time of acquisition of the metachronous NRM component by mafic dykes (21.8° ± 4.2° N) is consistent with the paleolatitudes of the northeastern edge of the North China Craton at the Late Permian/Early Triassic boundary.
      PubDate: 2022-06-01
      DOI: 10.1134/S1819714022030022
       
  • The Bolshoi Payalpan Volcano (Sredinny Range, Kamchatka): Problematic
           Aspects of the Convergence of Island-Arc and Within-Plate Petrological and
           Geochemical Signatures in the Magmatic System

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      Abstract: Abstract New age, mineralogical, geochemical, and isotope–geochemical data on the rocks of Bolshoi Payalpan Volcano (Sredinny Range, Kamchatka) are presented and compared with the available data on the Nosichan and Belogolovsky volcanoes within the common Belogolovsky volcanic center. Basalts of the neck and upper lava complex of Bolshoi Payalpan Volcano resemble withinplate-type trachybasalts of Belogolovsky Volcano, and basaltic andesites of the lower lava and the cone complex are similar to the island-arc rocks of Nosichan Volcano. Analysis of the data we obtained indicates that spatiotemporal association of intraplate and island-arc volcanism at Bolshoi Payalpan Volcano is not accidental, but may be caused by a change in the degree of melting and depth of a common deep source with the involvement of a mantle diapir. The Belogolovsky volcanic center formed in the Late Miocene–Early Pliocene rifting setting. Its evolution up to extinction proceeded in the same geodynamic setting with increasing depth coupled with a decreasing degree of melting of a mantle source. Rocks of Early–Middle Pliocene Nosichan Volcano retain island-arc signatures under incipient rifting conditions, since they are related to the mantle reservoir that is located at a shallower depth and experienced a higher degree of melting. There is good reason for consideration of large volcanic centers as self-developing geological systems. As the endogenous activity attenuates, the degree of melting decreases and the depth of melting increases, thus leading to a change from island-arc to withinplate volcanism. The volcanic center becomes extinct.
      PubDate: 2022-04-01
      DOI: 10.1134/S1819714022020063
       
  • Columbite–Tantalite of the Kester Deposit (Eastern Yakutia)

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      Abstract: Three mineral types of the columbite group have been revealed at the Kester Deposit (Eastern Yakutia), that is, columbite-(Fe), columbite-(Mn) and tantalite-(Mn), which are part of rare-metal granites, ongonites, albitites, and greisens. Columbite-(Mn) prevails: Ta/(Ta + Nb) = 0.30, and Mn/(Mn + Fe) = 0.64. The generalized formula of columbite–tantalite of the deposit is (Mn0.61Fe0.34)0.95(Nb1.37Ta0.58Ti0.04W0.03Sn0.01)2.03O6. Columbite–tantalite forms polymineral individuals with concentric growth zonality (from the core to the rim): columbite-(Fe) → columbite-(Mn) → tantalite-(Mn) + uranmicrolite → columbite-(Mn). In columbite of the Kester Deposit, WO3 is a typomorphic impurity, which is 2.67%, on average (formula coefficent, apfu is 0.04); the maximum value is 7.12% (apfu is 0.11). The isomorphic replacement of cations in the B position is assumed according to the following scheme: 2(Nb, Ta)5+ ↔ W6+ + Ti4+. In tantalite, SnO2 is a typomorphic impurity, which is 1.01%, on average (apfu is 0.03); the maximum value is 3.74% (apfu is 0.21). The paragenesis of the columbite group minerals includes albite, topaz, lepidolite, Nb-Ta-bearing cassiterite, wolframoixiolite, wolframite, U-Hf-bearing zircon, and struverite. At the Kester Deposit, the evolution of columbite–tantalite is accompanied by an increase in Ta/Nb, Mn/Fe, and Sn/W ratios manifested in the change of columbite by tantalite both in the process of the formation of ore-bearing rocks and in the rock series: rare-metal granites → albitites → greisens. The variation limits of Ta/(Ta + Nb) and Mn/(Mn + Fe) ratios are 0.07–0.74 and 0.16–0.96, respectively. The diversity and evolution of the columbite group minerals of the Kester Deposit indicate their belonging to the rare-metal ore-magmatic system, which includes ore-bearing rare-metal granites, albitites, and greisens. The presence of small intrusions of rare-metal granites and ongonites in the deposit area allows the forecasting of new objects with bedrock and placer columbite–tantalite mineralization.
      PubDate: 2022-04-01
      DOI: 10.1134/S1819714022020026
       
  • The Influence of the Structure and Composition of Lithotectonic Units on
           the Geochemical Specialization of Hydrothermal Mineralization of the
           Kolyma Terrane, Northeast Russia

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      Abstract: Abstract This study focused on the relationship between the mineralogical composition of hydrothermal mineralization and the structure and lithology of host units with specific reference to the Kolyma passive continental-margin terrane (Northeast Asia). The long geological history of the terrane was shown to be reflected in the geochemical specialization and distribution patterns of gold–rare metal and porphyry copper mineralization. The Proterozoic host units of the Kolyma region influenced the geochemistry and isotope composition of the ores. The imbricate–thrust structure of the terrane was formed in the Precambrian and underwent several episodes of reworking in the Phanerozoic, thus contributing to the repeated rejuvenation of the ores.
      PubDate: 2022-04-01
      DOI: 10.1134/S181971402202004X
       
  • The Deep Structure Model for Southern Kamchatka Based on 3D Density
           Modeling and Geological and Geophysical Data

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      Abstract: Comprehensive deep geophysical studies were conducted along the profile lines in the south of Kamchatka. The aim of the research was to study the lithosphere in the zone of present-day volcanism and active seismicity. Geological and geophysical models of the crust and upper mantle were constructed along the profiles. The results were obtained as part of two-dimensional modeling of the geophysical fields. However, the data analysis shows that the territory is characterized by a complex geological structure, which is shown by the three-dimensional distribution of gravitating masses. This article presents the results of volumetric density modeling carried out for the area of southern Kamchatka, including the Sea of Okhotsk and the Pacific water areas, for the first time. The model is based on the technique of three-dimensional imaging of 2D-modeling results obtained from the network of intersecting profiles. The 3D modeling has revealed the isodensity surfaces that border layers of high density (≥3.33 g/cm3). Thus, the surface revealed beneath the oceanic water area is interpreted as a fragment of the top of the subducting plate and the surface under the peninsula is identified as the top of the paleosubduction slab. A subhorizontal high-gradient zone (3.0–3.3 g/cm3) is recognized on the density sections that intersect the 3D model, which is identified as the Moho boundary. A model of the subduction interaction between the oceanic and continental lithospheric plates is proposed. A two-dimensional model shows the formation of a transitional layer between the Moho boundary of the overhanging lithospheric plate and the top of the paleosubducting oceanic plate. A low-density zone is distinguished in the transitional layer, where separate maximally low-density areas are identified as melting chambers. The conditions are shown for the formation of the crustal block, with abundant basic–ultrabasic intrusions and the diorite–granodiorite intrusive massif. All ore occurrences and a gold deposit of the Karymshinsky Ore Cluster are located within the contours of the projection onto the surface of the deep high-gradient zone that borders a low-density zone. Ore occurrences are genetically related to the zones of crustal weakness where the epithermal deposits are formed in closed hydrothermal systems. By analogy, it is possible to forecast gold ore occurrences in other areas of the projection of the high-gradient zone.
      PubDate: 2022-04-01
      DOI: 10.1134/S1819714022020075
       
  • Rare-Earth Element Mineralization in Argillized Granites of Southern
           Primorye: New Data

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      Abstract: Abstract Rare-earth element (REE) mineralization in weathered granites of Primorye is localized in the basement rocks and rocks surrounding coal-bearing basins, which have been recently deformed and undergone argillic metasomatism. It was shown that the clay material from the zones of intense argillization can be a source of deficient REE and yttrium. The ion-sorbed and carbonate REE+Y species in them in combination with the clay composition of most of the ores make it possible to use inexpensive and low-toxicity salt and hydrochloric acid solutions during heap leaching.
      PubDate: 2022-04-01
      DOI: 10.1134/S1819714022020038
       
  • The Records of Environmental Changes in Lacustrine–Swamp Sequences
           within the Mountain Area of Iturup Island since the Late Glacial Period

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      Abstract: We have received unique material on the development of the natural environment for the last 12 400 cal. yr. BP in the central part of Iturup Island. High-resolution paleoreconstructions have been based on the multi-proxy study of paleolake sediments found on the plateau (height 400–420 m) located northwest of the Baransky Volcano. For the first time, a record of paleogeographic events has been obtained for the Late Glacial and the Early Holocene. The age model is based on nine radiocarbon dates. Diatom analysis has made it possible to distinguish 11 stages of lake–swamp evolution. The paleolake reached its maximum depth at ~9890–7900 cal. yr. BP and became extinct at 1400 cal. yr. BP. The vegetation development stages and the landscape change factors have been restored. The Younger Dryas cooling recorded in Iturup was characterized by humidity changes. The role of forest vegetation rapidly increased at the Pleistocene–Holocene boundary of ~11 470 cal. yr. BP under warmer climatic conditions. Distribution of dwarf pine as an indicator of stable snow cover has been analyzed. Dark-coniferous forests existed in the mountainous part of the island since the Late Glacial and were the most widespread in the Early Holocene. The onset of birch forest expansion at 6200 cal. yr. BP was related to the intensification of volcanic activity and frequent ash falls. A number of identified cold events were enhanced by the weakening of the warm Soya Current. The intensive transfer of allochthonous pollen from the southern Kuril Islands and the Japanese Islands at 3540 cal. yr. BP is a sign of cyclogenesis intensification in the Kuril Islands. The Holocene climatic rhythms in the landscape development of the Iturup mountains, as well as the influence of warm and cold currents and other regional factors, have been analyzed.
      PubDate: 2022-04-01
      DOI: 10.1134/S1819714022020087
       
  • Correlation of the Acoustic Parameters and the Age of the Basal Horizons
           of the Cenozoic Sedimentary Cover, the Sea of Japan

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      Abstract: The velocity sections and acoustic parameters of the sedimentary cover in the Central (Japan), Yamato (Honshu), and Tsushima basins, and the Kita–Yamato Trough of the Sea of Japan, as well as the rocks of the basement and the Cenozoic cover of the submarine Yamato Rise were studied. A comparative analysis of similar parameters of the Cenozoic basins in the South China and East China marginal seas was performed. The relationship between the acoustic properties (P-wave velocity, Vp) of the basal horizons and the age of the Cenozoic cover in the above basins was analyzed. The values of Vp = 3.0–3.6 km/s have been validated as the acoustic parameter of Paleocene–Eocene sedimentary strata. According to the studies we performed, the basal layers in the supposed depocenters of the Japan basins (Central, Yamato, and Tsushima) have Vp = 3.0–3.3 km/s, which indicates the Paleocene–Eocene age of the onset of their formation.
      PubDate: 2022-04-01
      DOI: 10.1134/S1819714022020099
       
 
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