The Berezitovoe deposit is a large-sized Au-Ag-Zn-Pb deposit in the east of the SelengaStanovoi superterrane, Russia. Au-Ag orebodies are hosted by tourmaline-garnet-quartz-muscovite metasomatic rocks; Zn-Pb orebodies...The Berezitovoe deposit is a large-sized Au-Ag-Zn-Pb deposit in the east of the SelengaStanovoi superterrane, Russia. Au-Ag orebodies are hosted by tourmaline-garnet-quartz-muscovite metasomatic rocks; Zn-Pb orebodies are hosted by granodiorites, porphyritic granites and tourmalinegarnet-quartz-muscovite metasomatic rocks. These orebodies are surrounded by wall rocks dominated by the Tukuringra Complex granodiorites, porphyritic granites, and gneissic granodiorites. The alteration includes silicification and garnet, sericitization chloritization, carbonatization and kaollinization. LA-ICP-MS U-Pb zircon dating indicates that the gold mineralization can be divided into two stages in the Berezitovoe polymetallic gold deposit(at 363.5 ± 1.5 Ma, and133.4± 0.5).Hornblende-plagioclase gneisses of the Mogocha Group in the study area underwent Paleoproterozoic metamorphism(at 1870 ± 7.8 and 2400 ± 13 Ma), gneissic granodiorite of the Tukuringra Complex yields a late Paleozoic magmatic age(at 379.2 ± 1.1 Ma),and subalkaline porphyritic granitoid of the Amudzhikan Complex yield late Mesozoic magmatic ages(133-139 and 150-163 Ma). Granodiorites of the Tukuringra Complex in the study area have high concentrations of SiO_2(average of 60.9 wt%), are aluminum-oversaturated(average A/CNK of 1.49), are enriched in the large ion lithophile elements(e.g.,K, Rb, and Ba), U, Th, and Pb, are depleted in high field strength elements(e.g., Ta, Nb, and Ti), and have slightly negative Eu and no Ce anomalies in chondrite-normalized rare earth element diagrams.Fluid inclusions from quartz veins include three types: aqueous two-phase, CO_2-bearing three-phase,and pure CO_2. Aqueous two-phase inclusions homogenize at 167℃-249℃ and have salinities of 4.32%-9.47% NaCl equivalent, densities of 0.86-0.95 g/cm^3, and formed at depths of 0.52-0.94 km. In comparison, the C0_2-bearing three-phase inclusions have homogenization temperatures of 265℃-346℃,salinities of 7.14%-11.57% NaCl equivalent, and total densities of 0.62-0.67 g/cm^3. The geochemical and zircon U-Pb data and the regional tectonic evolution of the study area, show that the Berezitovoe polymetallic gold deposit formed in an island arc or active continental margin setting, most probably related to late Paleozoic subduction of Okhotsk Ocean crust beneath the Siberian Plate.展开更多
Studied waters belong to warm(T=30-50℃),alkaline(pH=8.9-9.3),low mineralized(TDS<235 mg/1)Na-HCO_3 or Na-SO_4-HCO_3 thermal waters with high content of SiO_2(up to 81 mg/l)and F(up to 3.9 mg/1),occur on modern vol...Studied waters belong to warm(T=30-50℃),alkaline(pH=8.9-9.3),low mineralized(TDS<235 mg/1)Na-HCO_3 or Na-SO_4-HCO_3 thermal waters with high content of SiO_2(up to 81 mg/l)and F(up to 3.9 mg/1),occur on modern volcano-tectonic rejuvenated areas of Eastern Sikhote-Alin orogenic belt.Low^3He concentration as well as N_2/O_2 and N_2/Ar ratios exclude influence of deep mantle fluid.New rare earth element data constrain our understandmg of water-rock interaction occurring in the water source region.Meteoric origin of waters is proved by stable isotope values varying from-71‰to-136.1‰and from-10.8‰to-18.8‰forδ~2U andδ^(18)O respectively.REE patterns reflect high pH,resultfing from water-rock interaction and oxidative conditions.Calculations of deep aquifer temperature using Na-K and quartz geothermometers show 116.8-131.1°C and 82.2-125.8℃respectively.Presence of deep faults both with abnormal thermal gradient(~45-50 K/km)define unique geochemical shape of thermal waters of Sikhote-Alin,area,where no present volcanic activity is registered.展开更多
New isotopic,geochemical and geochronological data justify the widespread occurrence of middle Paleocene to early Eocene(60–53 Ma)post-subduction felsic magmatism across the entire Sikhote-Alin territory(southeastern...New isotopic,geochemical and geochronological data justify the widespread occurrence of middle Paleocene to early Eocene(60–53 Ma)post-subduction felsic magmatism across the entire Sikhote-Alin territory(southeastern Russia),conform with previous observations in Northeast China,the southern Korean Peninsula,and the Inner Zone of Japan.This igneous activity in East Asia coincided with the reactivation(after tectonic quiescence between~93–60Ma)of left-lateral strike-slip displacements along the Tan-Lu and Central Sikhote-Alin faults and with the post-60 Ma cessation of subduction/accretion recorded in the Shimanto belt of SW Japan.The Sikhote-Alin post-subduction igneous A-type rocks present diverse mineralogical and geochemical features that suggest interactions of the subducting plate with anhydrous mantle upwelling through slab tears in the continental margin.The middle Paleocene–early Eocene magmatismis not related to subduction but is synchronous with strikeslip tectonics and the termination of accretionary prism development,suggesting a shift in tectonic regime from oceanic plate subduction at a convergent margin to parallel sliding and initiation of a transformcontinental margin.These new observations are inconsistent with the current tectonic model of 60–50 Ma Izanagi-Pacific ridge subduction beneath East Asian continental margin.展开更多
this work focuses on one of the critical points of Earth's history when the Solar System passed through the most distant point of its galactic orbit. During this event, Earth may have suffered from maximum extensi...this work focuses on one of the critical points of Earth's history when the Solar System passed through the most distant point of its galactic orbit. During this event, Earth may have suffered from maximum extension, associated with its relative proximity to the Sun at that time, followed by long-term contraction related to its later distancing. This paper is based on generalized data on the Cretaceous evolution of the Earth as a whole and of East Asia in particular. The evidence suggests that major geological processes at this time may be interpreted as transitional changes in the state of Earth. A liquid nature of its core may have reacted to the gravitational and electromagnetic transformations. When the cosmic changes took place at 135-120 Ma, more turbulent flows in the outer core would have favoured the rise of voluminous magmatic plumes and associated fluid flows. These would substantially transform the mantle, crust, hydrosphere, biosphere and atmosphere. In particular, plume-related melting of overlying subducting slabs and lower continental crust could have initiated numerous adakitic melts that formed the East Asian Adakitic Province. These and associated juvenile events produced numerous metallic ore, coal, gas and oil deposits. The Cretaceous is one of the most significant resource-producing periods.展开更多
This study presents new chemical and isotopic data on the two types of cold high pCO2 groundwaters located in the Mukhen deposit (Far East of Russia). The first type belongs to HCO3-Ca-Mg waters with a relatively low ...This study presents new chemical and isotopic data on the two types of cold high pCO2 groundwaters located in the Mukhen deposit (Far East of Russia). The first type belongs to HCO3-Ca-Mg waters with a relatively low TDS (up to 1.7 g/l) and high concentrations of Fe2+, Mn2+, Ba2+, and SiO2. The second type is of HCO3-Na water with high TDS (up to 14 g/l) and elevated Li+, B, Sr2+, Br?, and I?. New isotopic data of water (δ18O, δD and 3H) and gas (δ13CTIC) phases along with a detailed geological and hydrogeological investigation of the study area allowed identifying genesis of both the mineral waters. The residence time of groundwaters were calculated as well. It was established that the origin of the high pCO2 groundwaters was caused by active faulting and CO2 venting in the subsurface zone.展开更多
In the southeast part of the North-Asian craton, several ring basite-ultrabasite plutons have been recognized, with which the commercial placers of platinoids associate. Analysis of the known geodynamic models of the ...In the southeast part of the North-Asian craton, several ring basite-ultrabasite plutons have been recognized, with which the commercial placers of platinoids associate. Analysis of the known geodynamic models of the region formation and materials of seismic tomography showed that the subduction processes, that actively manifested themselves in the Asia-Pacific convergence zone in Mesozoic, were responsible for initiation of the stagnated oceanic slab. Its NE and SW boundaries appear to coincide with the transform faults. Projection of the transform fault, bordering the above mentioned slab in the NEN, coincides with the Konder-Feklistovsky metallogenic belt distinguished earlier and its Aldan (Inaglinsky) member. Higher platinum content of ring massifs of the belt is controlled by the influence of the lower mantle derivatives on the ascending upper mantle plumes.展开更多
The sources of large and unique platinum-metal placers were the zonal alkali-ultrabasic massifs becoming active in the Cretaceous time that gravitated to the periphery of the areal of the North-Asian Superplume (NAS) ...The sources of large and unique platinum-metal placers were the zonal alkali-ultrabasic massifs becoming active in the Cretaceous time that gravitated to the periphery of the areal of the North-Asian Superplume (NAS) influence. Origin of the conditions favorable for the formation of the placer platinum presence in the region is governed by the plume ore-generating magmatism of several generations (in Proterozoic and Phanerozoic). Ultramafite-mafite magmatism was responsible for the origin of the stratified zonal massifs subjected in the Late Paleozoic and Mesozoic to the action of granitogene derivations of the NAS. The latter provided the development of the ore-forming magmagene-fluid-metasomatic processes and favorable conditions for the platinum group elements concentration.展开更多
The first data of geochemical study of the Benevka Section cherty rocks belonging to the Taukha terrane of the Sikhote-Alin Late Jurassic–Early Cretaceous accretionary prism, Russia Far East are presented. These data...The first data of geochemical study of the Benevka Section cherty rocks belonging to the Taukha terrane of the Sikhote-Alin Late Jurassic–Early Cretaceous accretionary prism, Russia Far East are presented. These data demonstrate essential distinctions of major, trace and rare earth element concentrations in different parts of the measured stratigraphic section. The lower chert horizons exhibit high Fe2O3 and Mn O contents, low concentrations of Al2O3 and Ti O2, relatively high V/Y ratio, and extremely low value of negative Ce anomaly. In contrast the upper horizons composed of clayey cherts and siliceous mudstones are characterized by high Al2O3, Ti O2 and K2 O contents, low Fe2O3 and Mn O values, low V/Y ratio, and slightly negative Ce anomaly. In the middle part of the Benevka Section, in which cherts gradually changed to clayey cherts, intermediate geochemical characteristics are present. Based on these data obtained the depositional environments correspond to proximal to the spreding ridge, open-ocean and near continental margin regimes were successfully reconstructed from bottom to top of the Benevka Section, that indicate that significant horizontal movement took place of the sea-floor, on which the cherts were deposited.展开更多
The article presents the results of a comparative geochemical study of cherts and siliceous-clayey rocks composing the tectono-sedimentary complexes of various structural levels of the Taukha terrain of the Sikhote-Al...The article presents the results of a comparative geochemical study of cherts and siliceous-clayey rocks composing the tectono-sedimentary complexes of various structural levels of the Taukha terrain of the Sikhote-Alin Late Jurassic-Early Cretaceous accretionary prism.The data obtained show that the same-aged parts of the crosssections of the cherty-terrigenous sequences of the terrane lower and middle structural levels are characterized by significantly different contents and distribution patterns of major petrogenic oxides,trace,and rare-earth elements due to their accumulation in various facies of oceanic zones.The set of geochemical data indicates that the formation of both tectono-sedimentary complexes was carried out differently,gradually replacing each others’facies oceanic zones,and started in the near-spreading ridge area,then in the pelagial,and completed in the continental-margin deposition environment.Based on the time interval of the facies conditions changing for each complex(i.e.,time of transition from one facies zone to another),the speeds of a paleo-oceanic plate motion(and,correspondingly,the speeds of spreading)for individual intervals of the Jurassic were calculated.Differences in the spreading speeds at various sites of a paleorift zone caused the turning of a paleocontinent margin contour and spreading ridge axis at the perpendicular position,which in turn caused change of the geodynamic mode on the eastern margin of the PaleoAsian continent at the Jurassic-Cretaceous transition.展开更多
The Berezitovoe deposit in the Sergachi volcano-plutonic and metallogenic belt preserves evidence for polymetallic mineralization of multiple stages.The steeply dipping gamet-tourmaline-muscovite-quartz metasomatites(...The Berezitovoe deposit in the Sergachi volcano-plutonic and metallogenic belt preserves evidence for polymetallic mineralization of multiple stages.The steeply dipping gamet-tourmaline-muscovite-quartz metasomatites(with K-Ar ages of 132 ± 2.9 and 127 ± 4.4 Ma) carry two distinct stages of mineralization developed at different times:(1) polymetallic mineralization and(2) gold-quartz.The deposit is located within Paleozoic gneissose granitoids of the Pikansky complex(dated as 379 ± 1.1 Ma by zircon U-Pb method) intruded by early Cretaceous porphyry-like granites of the Haikta pluton(dated as137 ± 0.67 Ma by zircon U-Pb method) and late Cretaceous dikes of porphyrites,porphyries,and lamprophyres.Evidence suggests the action of late gold-bearing hydrothermal fluids on the early polymetallic ores and the selective mobilization of some elements from these lead to redeposition together with complex sulphosalts.展开更多
A groundwater radon monitoring in the southern and western part of Sakhalin Island was carried out in 2014 in order to study the correlation between radon anomalies and the seismic activity of the region. The objects ...A groundwater radon monitoring in the southern and western part of Sakhalin Island was carried out in 2014 in order to study the correlation between radon anomalies and the seismic activity of the region. The objects of investigations were located within large tectonic dislocations of the island—the southern part of the Central Sakhalin fault and the central part of the West Sakhalin fault. The soil gas monitoring was carried out using a Sirad probe (Quarta-Rad, Russia) and the continuous radon monitoring in the groundwater was carried out using a Radon Seismic Station (CPC-05, NTM-Zashita, Russia). The effect of geochemical parameters, namely, temperature, pressure and conductivity on the radon emission has been studied. The present work contains an analytical protocol which is based on the analysis of radon emitted from the fault planes, a geo- chemical precursor when predicting the tectonic activity.展开更多
This article is to reveal and corroborate the geodynamic conditions for the formation of Cretaceous sedimentary basins of the Russian Far East. The conclusions are based on the comprehensive analysis of the extensive ...This article is to reveal and corroborate the geodynamic conditions for the formation of Cretaceous sedimentary basins of the Russian Far East. The conclusions are based on the comprehensive analysis of the extensive mapping materials and special structural field studies. It has been found that sedimentary basins developed as rift-grabens were synchronous with formation of horsts separating the basins. The imbricated-thrust structures, which are morphologically similar to the subduction-related accretionary prisms but nevertheless different in nature, were formed within the transition zone between the uplifted structures and basins. A synsedimentary supply of a mantle-derived material into basins points to a temporarily continual extension of continental lithosphere. The lithospheric plates moved apart during the strike slip faulting with the subsequent involvement of convective mantle flows and plume diapirism (continental spreading?). Because of horizontal movement of lithospheric plates, horstlike uplifts were formed in the frontal zones. In sedimentary formations overlapping the lithospheric plates, the synsedimentary imbricated-thrust structures were developed, favouring a growth of the uplifts in lateral direction toward the axial zones of rift-grabens. Synchronously with basaltic volcanic activity in the rift-graben zones, basic-ultrabasic intrusive magmatism occurred within the limits of the contiguous uplifts.展开更多
There are known brown coal deposits in Primorsky Krai(Russian Federation),where coals contain rare elements(Ge,U,REE,etc.)up to industrial concentrations.One of the known metalliferous coals is the Rakovka coal-bearin...There are known brown coal deposits in Primorsky Krai(Russian Federation),where coals contain rare elements(Ge,U,REE,etc.)up to industrial concentrations.One of the known metalliferous coals is the Rakovka coal-bearing depression,located on the southern edge of the Khanka(Prikhankaiskaya)Lowland,with an area of about 70 km2.Rare-metal granites with a developed weathering crust are spread in its basement and flanks.The structural conditions forming the depression were studied using measurements of orientations of structural elements(layering,contacts,veins,and dikes)with regard to kinematic conditions of faulting.The coal and host rocks were sampled in sections in the cross strike of the coal seam.Granites and dikes cutting them were sampled by separate rock chip samples.The chemical composition and element content were determined for all samples.It was found that the adjacent rocks played a major role in the formation of the Rakovka rare-metal-coal deposit.The rare-elements enrichment is not associated with active tectonics,faults,and hydrothermal sources,as was previously assumed.Rather,it was caused by the hydrogenic and clastogenic removal of these metals from the weathering crust of granites of the depression's flanks and argillated basite dikes cutting the granites.The hydrogenic nature of the anomalous accumulation of U in sorbed form on organic matter of coals is confirmed by the predominant enrichment of low-ash beds.Rare earth elements entered coal seams both in mineral and dissolved forms.A model of REE and uranium input into the coal-bearing sediments of the Rakovka depression was proposed.展开更多
Garnet megacryst with a multiphase inclusion from intraplate alkali basalts of the Shavaryn Tsaram(Tariat,Mongolia)was the object of the study.This unusual aggregate consists of porous glass,Ti-rich biotite,orthopyrox...Garnet megacryst with a multiphase inclusion from intraplate alkali basalts of the Shavaryn Tsaram(Tariat,Mongolia)was the object of the study.This unusual aggregate consists of porous glass,Ti-rich biotite,orthopyroxene,spinel,clinopyroxene,olivine,and ilmenite.Win TWQ 2.32 thermodynamic simulation of this system revealed a few intervals of equilibrium.Pressure and temperature adjustment reflected in the paragenetic minerals of the melt pocket.The capture of already crystallised garnet megacryst was at P=0.8-1 GPa and T=1120-1160℃.Mineral crystallisation inside the melt pocket,accompanied by external inputs,occurred at P=0.75-0.95 GPa;T=790-1120℃.Symplectite assemblage formed in the garnet megacryst due to decomposition at(P=0.55-0.7 GPa;T=850-930℃).The study of the oxygen isotope content in primary garnet and biotite of the melt pocket showed that the δ^(18)O_(VSMOW) values are the same and correspond to that of typical mantle xenoliths.However,the chemical and microcomponent composition of the melt pocket minerals reveals a material that differs from basalts and peridotites.Thus,it has been revealed that the multiphase inclusion in the garnet megacryst formed not only on account of the garnet’s substance,but also due to the entrapped material of the Earth’s interior.展开更多
Diatoms from Middle Miocene deposits of Khanka Lake’s northwestern shore (Primorye) were studied using light and scanning microscopes. The analyses of diatom flora composition and species diversity showed that there ...Diatoms from Middle Miocene deposits of Khanka Lake’s northwestern shore (Primorye) were studied using light and scanning microscopes. The analyses of diatom flora composition and species diversity showed that there was a dominace of several taxa that made possible the recognition of two diatom complexes. The lower complex differs from the upper one by higher species diversity, by presence of many subtropical diatoms and absence of pronounced dominant species. Differences between the complexes can be explained by the progressing climatic cooling and predominance of fluvial-lakustrine sedimentation over the typically lake one due to development of a wide system of river valleys.展开更多
Different types of groundwater manifestations occurring on modern structure of the Baransky volcano were studied. Volcanic and seismic activity influences strongly on hydrology and hydrochemistry of the groundwater of...Different types of groundwater manifestations occurring on modern structure of the Baransky volcano were studied. Volcanic and seismic activity influences strongly on hydrology and hydrochemistry of the groundwater of the watershed of Sernaya river. Three types of fluids have been established: volcanic-heated, steam-heated and mature. Existing model of hydrothermal system of Baransky volcano was confirmed using geothermometry and hydrochemical calculations. Thus Baransky volcano is a complex object with atmospheric recharge, deep diorite body as heat source and thick fractured altered andesitic water reservoir, where different types of water springs can emerge.展开更多
基金funded bythe Chinese Geological Survey Programme(Grant Nos.1212011120342,1212011121088)the Doctoral Scientific Research Foundation of Liaoning Provicen(Grant Nos.201601370)the Sixth Batch Production Technology Problem Foundation of Liaoning Technical University(Grant Nos.20160084T)
文摘The Berezitovoe deposit is a large-sized Au-Ag-Zn-Pb deposit in the east of the SelengaStanovoi superterrane, Russia. Au-Ag orebodies are hosted by tourmaline-garnet-quartz-muscovite metasomatic rocks; Zn-Pb orebodies are hosted by granodiorites, porphyritic granites and tourmalinegarnet-quartz-muscovite metasomatic rocks. These orebodies are surrounded by wall rocks dominated by the Tukuringra Complex granodiorites, porphyritic granites, and gneissic granodiorites. The alteration includes silicification and garnet, sericitization chloritization, carbonatization and kaollinization. LA-ICP-MS U-Pb zircon dating indicates that the gold mineralization can be divided into two stages in the Berezitovoe polymetallic gold deposit(at 363.5 ± 1.5 Ma, and133.4± 0.5).Hornblende-plagioclase gneisses of the Mogocha Group in the study area underwent Paleoproterozoic metamorphism(at 1870 ± 7.8 and 2400 ± 13 Ma), gneissic granodiorite of the Tukuringra Complex yields a late Paleozoic magmatic age(at 379.2 ± 1.1 Ma),and subalkaline porphyritic granitoid of the Amudzhikan Complex yield late Mesozoic magmatic ages(133-139 and 150-163 Ma). Granodiorites of the Tukuringra Complex in the study area have high concentrations of SiO_2(average of 60.9 wt%), are aluminum-oversaturated(average A/CNK of 1.49), are enriched in the large ion lithophile elements(e.g.,K, Rb, and Ba), U, Th, and Pb, are depleted in high field strength elements(e.g., Ta, Nb, and Ti), and have slightly negative Eu and no Ce anomalies in chondrite-normalized rare earth element diagrams.Fluid inclusions from quartz veins include three types: aqueous two-phase, CO_2-bearing three-phase,and pure CO_2. Aqueous two-phase inclusions homogenize at 167℃-249℃ and have salinities of 4.32%-9.47% NaCl equivalent, densities of 0.86-0.95 g/cm^3, and formed at depths of 0.52-0.94 km. In comparison, the C0_2-bearing three-phase inclusions have homogenization temperatures of 265℃-346℃,salinities of 7.14%-11.57% NaCl equivalent, and total densities of 0.62-0.67 g/cm^3. The geochemical and zircon U-Pb data and the regional tectonic evolution of the study area, show that the Berezitovoe polymetallic gold deposit formed in an island arc or active continental margin setting, most probably related to late Paleozoic subduction of Okhotsk Ocean crust beneath the Siberian Plate.
文摘Studied waters belong to warm(T=30-50℃),alkaline(pH=8.9-9.3),low mineralized(TDS<235 mg/1)Na-HCO_3 or Na-SO_4-HCO_3 thermal waters with high content of SiO_2(up to 81 mg/l)and F(up to 3.9 mg/1),occur on modern volcano-tectonic rejuvenated areas of Eastern Sikhote-Alin orogenic belt.Low^3He concentration as well as N_2/O_2 and N_2/Ar ratios exclude influence of deep mantle fluid.New rare earth element data constrain our understandmg of water-rock interaction occurring in the water source region.Meteoric origin of waters is proved by stable isotope values varying from-71‰to-136.1‰and from-10.8‰to-18.8‰forδ~2U andδ^(18)O respectively.REE patterns reflect high pH,resultfing from water-rock interaction and oxidative conditions.Calculations of deep aquifer temperature using Na-K and quartz geothermometers show 116.8-131.1°C and 82.2-125.8℃respectively.Presence of deep faults both with abnormal thermal gradient(~45-50 K/km)define unique geochemical shape of thermal waters of Sikhote-Alin,area,where no present volcanic activity is registered.
基金by the Russian Foundation for Basic Research and the National Natural Science Foundation of China for scientific project No.19-55-53008by the partial financial support of the Russian Foundation for Basic Research(No.19-05-00100).
文摘New isotopic,geochemical and geochronological data justify the widespread occurrence of middle Paleocene to early Eocene(60–53 Ma)post-subduction felsic magmatism across the entire Sikhote-Alin territory(southeastern Russia),conform with previous observations in Northeast China,the southern Korean Peninsula,and the Inner Zone of Japan.This igneous activity in East Asia coincided with the reactivation(after tectonic quiescence between~93–60Ma)of left-lateral strike-slip displacements along the Tan-Lu and Central Sikhote-Alin faults and with the post-60 Ma cessation of subduction/accretion recorded in the Shimanto belt of SW Japan.The Sikhote-Alin post-subduction igneous A-type rocks present diverse mineralogical and geochemical features that suggest interactions of the subducting plate with anhydrous mantle upwelling through slab tears in the continental margin.The middle Paleocene–early Eocene magmatismis not related to subduction but is synchronous with strikeslip tectonics and the termination of accretionary prism development,suggesting a shift in tectonic regime from oceanic plate subduction at a convergent margin to parallel sliding and initiation of a transformcontinental margin.These new observations are inconsistent with the current tectonic model of 60–50 Ma Izanagi-Pacific ridge subduction beneath East Asian continental margin.
基金supported by the National Natural Science Foundation of China(No.41420104001)the ‘111’ Project(No.B17042)
文摘this work focuses on one of the critical points of Earth's history when the Solar System passed through the most distant point of its galactic orbit. During this event, Earth may have suffered from maximum extension, associated with its relative proximity to the Sun at that time, followed by long-term contraction related to its later distancing. This paper is based on generalized data on the Cretaceous evolution of the Earth as a whole and of East Asia in particular. The evidence suggests that major geological processes at this time may be interpreted as transitional changes in the state of Earth. A liquid nature of its core may have reacted to the gravitational and electromagnetic transformations. When the cosmic changes took place at 135-120 Ma, more turbulent flows in the outer core would have favoured the rise of voluminous magmatic plumes and associated fluid flows. These would substantially transform the mantle, crust, hydrosphere, biosphere and atmosphere. In particular, plume-related melting of overlying subducting slabs and lower continental crust could have initiated numerous adakitic melts that formed the East Asian Adakitic Province. These and associated juvenile events produced numerous metallic ore, coal, gas and oil deposits. The Cretaceous is one of the most significant resource-producing periods.
文摘This study presents new chemical and isotopic data on the two types of cold high pCO2 groundwaters located in the Mukhen deposit (Far East of Russia). The first type belongs to HCO3-Ca-Mg waters with a relatively low TDS (up to 1.7 g/l) and high concentrations of Fe2+, Mn2+, Ba2+, and SiO2. The second type is of HCO3-Na water with high TDS (up to 14 g/l) and elevated Li+, B, Sr2+, Br?, and I?. New isotopic data of water (δ18O, δD and 3H) and gas (δ13CTIC) phases along with a detailed geological and hydrogeological investigation of the study area allowed identifying genesis of both the mineral waters. The residence time of groundwaters were calculated as well. It was established that the origin of the high pCO2 groundwaters was caused by active faulting and CO2 venting in the subsurface zone.
文摘In the southeast part of the North-Asian craton, several ring basite-ultrabasite plutons have been recognized, with which the commercial placers of platinoids associate. Analysis of the known geodynamic models of the region formation and materials of seismic tomography showed that the subduction processes, that actively manifested themselves in the Asia-Pacific convergence zone in Mesozoic, were responsible for initiation of the stagnated oceanic slab. Its NE and SW boundaries appear to coincide with the transform faults. Projection of the transform fault, bordering the above mentioned slab in the NEN, coincides with the Konder-Feklistovsky metallogenic belt distinguished earlier and its Aldan (Inaglinsky) member. Higher platinum content of ring massifs of the belt is controlled by the influence of the lower mantle derivatives on the ascending upper mantle plumes.
文摘The sources of large and unique platinum-metal placers were the zonal alkali-ultrabasic massifs becoming active in the Cretaceous time that gravitated to the periphery of the areal of the North-Asian Superplume (NAS) influence. Origin of the conditions favorable for the formation of the placer platinum presence in the region is governed by the plume ore-generating magmatism of several generations (in Proterozoic and Phanerozoic). Ultramafite-mafite magmatism was responsible for the origin of the stratified zonal massifs subjected in the Late Paleozoic and Mesozoic to the action of granitogene derivations of the NAS. The latter provided the development of the ore-forming magmagene-fluid-metasomatic processes and favorable conditions for the platinum group elements concentration.
基金financially supported by the President of the Russian Federation (No. 1159.2014.5)the Far Eastern Branch of the Russian Academy of Sciences (No. 15-1-2-013-2)
文摘The first data of geochemical study of the Benevka Section cherty rocks belonging to the Taukha terrane of the Sikhote-Alin Late Jurassic–Early Cretaceous accretionary prism, Russia Far East are presented. These data demonstrate essential distinctions of major, trace and rare earth element concentrations in different parts of the measured stratigraphic section. The lower chert horizons exhibit high Fe2O3 and Mn O contents, low concentrations of Al2O3 and Ti O2, relatively high V/Y ratio, and extremely low value of negative Ce anomaly. In contrast the upper horizons composed of clayey cherts and siliceous mudstones are characterized by high Al2O3, Ti O2 and K2 O contents, low Fe2O3 and Mn O values, low V/Y ratio, and slightly negative Ce anomaly. In the middle part of the Benevka Section, in which cherts gradually changed to clayey cherts, intermediate geochemical characteristics are present. Based on these data obtained the depositional environments correspond to proximal to the spreding ridge, open-ocean and near continental margin regimes were successfully reconstructed from bottom to top of the Benevka Section, that indicate that significant horizontal movement took place of the sea-floor, on which the cherts were deposited.
基金supported in part by Grant of the RFBR-GFEN,Project No.19-55-53008。
文摘The article presents the results of a comparative geochemical study of cherts and siliceous-clayey rocks composing the tectono-sedimentary complexes of various structural levels of the Taukha terrain of the Sikhote-Alin Late Jurassic-Early Cretaceous accretionary prism.The data obtained show that the same-aged parts of the crosssections of the cherty-terrigenous sequences of the terrane lower and middle structural levels are characterized by significantly different contents and distribution patterns of major petrogenic oxides,trace,and rare-earth elements due to their accumulation in various facies of oceanic zones.The set of geochemical data indicates that the formation of both tectono-sedimentary complexes was carried out differently,gradually replacing each others’facies oceanic zones,and started in the near-spreading ridge area,then in the pelagial,and completed in the continental-margin deposition environment.Based on the time interval of the facies conditions changing for each complex(i.e.,time of transition from one facies zone to another),the speeds of a paleo-oceanic plate motion(and,correspondingly,the speeds of spreading)for individual intervals of the Jurassic were calculated.Differences in the spreading speeds at various sites of a paleorift zone caused the turning of a paleocontinent margin contour and spreading ridge axis at the perpendicular position,which in turn caused change of the geodynamic mode on the eastern margin of the PaleoAsian continent at the Jurassic-Cretaceous transition.
基金the financial support of the Presidium and Far East Branch of the Russian Academy of Sciences (Grant No.15-1-2-019)the Russian Foundation for Basic Research(Grant No.15-05-00809)+1 种基金supported by the Talent Award to M.Santosh from the 1000 Plan of the Chinese Governmentthe Foreign Expert grants from China University of Geosciences(Beijing)
文摘The Berezitovoe deposit in the Sergachi volcano-plutonic and metallogenic belt preserves evidence for polymetallic mineralization of multiple stages.The steeply dipping gamet-tourmaline-muscovite-quartz metasomatites(with K-Ar ages of 132 ± 2.9 and 127 ± 4.4 Ma) carry two distinct stages of mineralization developed at different times:(1) polymetallic mineralization and(2) gold-quartz.The deposit is located within Paleozoic gneissose granitoids of the Pikansky complex(dated as 379 ± 1.1 Ma by zircon U-Pb method) intruded by early Cretaceous porphyry-like granites of the Haikta pluton(dated as137 ± 0.67 Ma by zircon U-Pb method) and late Cretaceous dikes of porphyrites,porphyries,and lamprophyres.Evidence suggests the action of late gold-bearing hydrothermal fluids on the early polymetallic ores and the selective mobilization of some elements from these lead to redeposition together with complex sulphosalts.
文摘A groundwater radon monitoring in the southern and western part of Sakhalin Island was carried out in 2014 in order to study the correlation between radon anomalies and the seismic activity of the region. The objects of investigations were located within large tectonic dislocations of the island—the southern part of the Central Sakhalin fault and the central part of the West Sakhalin fault. The soil gas monitoring was carried out using a Sirad probe (Quarta-Rad, Russia) and the continuous radon monitoring in the groundwater was carried out using a Radon Seismic Station (CPC-05, NTM-Zashita, Russia). The effect of geochemical parameters, namely, temperature, pressure and conductivity on the radon emission has been studied. The present work contains an analytical protocol which is based on the analysis of radon emitted from the fault planes, a geo- chemical precursor when predicting the tectonic activity.
基金Supported partially by the Russian Foundation for Basic Research (Grant No. 08-05-90300-Viet_a)
文摘This article is to reveal and corroborate the geodynamic conditions for the formation of Cretaceous sedimentary basins of the Russian Far East. The conclusions are based on the comprehensive analysis of the extensive mapping materials and special structural field studies. It has been found that sedimentary basins developed as rift-grabens were synchronous with formation of horsts separating the basins. The imbricated-thrust structures, which are morphologically similar to the subduction-related accretionary prisms but nevertheless different in nature, were formed within the transition zone between the uplifted structures and basins. A synsedimentary supply of a mantle-derived material into basins points to a temporarily continual extension of continental lithosphere. The lithospheric plates moved apart during the strike slip faulting with the subsequent involvement of convective mantle flows and plume diapirism (continental spreading?). Because of horizontal movement of lithospheric plates, horstlike uplifts were formed in the frontal zones. In sedimentary formations overlapping the lithospheric plates, the synsedimentary imbricated-thrust structures were developed, favouring a growth of the uplifts in lateral direction toward the axial zones of rift-grabens. Synchronously with basaltic volcanic activity in the rift-graben zones, basic-ultrabasic intrusive magmatism occurred within the limits of the contiguous uplifts.
基金The reported study was funded by RFBR and NSFC,Project Number 21-55-53013.
文摘There are known brown coal deposits in Primorsky Krai(Russian Federation),where coals contain rare elements(Ge,U,REE,etc.)up to industrial concentrations.One of the known metalliferous coals is the Rakovka coal-bearing depression,located on the southern edge of the Khanka(Prikhankaiskaya)Lowland,with an area of about 70 km2.Rare-metal granites with a developed weathering crust are spread in its basement and flanks.The structural conditions forming the depression were studied using measurements of orientations of structural elements(layering,contacts,veins,and dikes)with regard to kinematic conditions of faulting.The coal and host rocks were sampled in sections in the cross strike of the coal seam.Granites and dikes cutting them were sampled by separate rock chip samples.The chemical composition and element content were determined for all samples.It was found that the adjacent rocks played a major role in the formation of the Rakovka rare-metal-coal deposit.The rare-elements enrichment is not associated with active tectonics,faults,and hydrothermal sources,as was previously assumed.Rather,it was caused by the hydrogenic and clastogenic removal of these metals from the weathering crust of granites of the depression's flanks and argillated basite dikes cutting the granites.The hydrogenic nature of the anomalous accumulation of U in sorbed form on organic matter of coals is confirmed by the predominant enrichment of low-ash beds.Rare earth elements entered coal seams both in mineral and dissolved forms.A model of REE and uranium input into the coal-bearing sediments of the Rakovka depression was proposed.
文摘Garnet megacryst with a multiphase inclusion from intraplate alkali basalts of the Shavaryn Tsaram(Tariat,Mongolia)was the object of the study.This unusual aggregate consists of porous glass,Ti-rich biotite,orthopyroxene,spinel,clinopyroxene,olivine,and ilmenite.Win TWQ 2.32 thermodynamic simulation of this system revealed a few intervals of equilibrium.Pressure and temperature adjustment reflected in the paragenetic minerals of the melt pocket.The capture of already crystallised garnet megacryst was at P=0.8-1 GPa and T=1120-1160℃.Mineral crystallisation inside the melt pocket,accompanied by external inputs,occurred at P=0.75-0.95 GPa;T=790-1120℃.Symplectite assemblage formed in the garnet megacryst due to decomposition at(P=0.55-0.7 GPa;T=850-930℃).The study of the oxygen isotope content in primary garnet and biotite of the melt pocket showed that the δ^(18)O_(VSMOW) values are the same and correspond to that of typical mantle xenoliths.However,the chemical and microcomponent composition of the melt pocket minerals reveals a material that differs from basalts and peridotites.Thus,it has been revealed that the multiphase inclusion in the garnet megacryst formed not only on account of the garnet’s substance,but also due to the entrapped material of the Earth’s interior.
文摘Diatoms from Middle Miocene deposits of Khanka Lake’s northwestern shore (Primorye) were studied using light and scanning microscopes. The analyses of diatom flora composition and species diversity showed that there was a dominace of several taxa that made possible the recognition of two diatom complexes. The lower complex differs from the upper one by higher species diversity, by presence of many subtropical diatoms and absence of pronounced dominant species. Differences between the complexes can be explained by the progressing climatic cooling and predominance of fluvial-lakustrine sedimentation over the typically lake one due to development of a wide system of river valleys.
文摘Different types of groundwater manifestations occurring on modern structure of the Baransky volcano were studied. Volcanic and seismic activity influences strongly on hydrology and hydrochemistry of the groundwater of the watershed of Sernaya river. Three types of fluids have been established: volcanic-heated, steam-heated and mature. Existing model of hydrothermal system of Baransky volcano was confirmed using geothermometry and hydrochemical calculations. Thus Baransky volcano is a complex object with atmospheric recharge, deep diorite body as heat source and thick fractured altered andesitic water reservoir, where different types of water springs can emerge.
