检索结果-南通市图书馆

Geoscience Frontiers 2020年第4期11卷 1289-1303页

作者： Ivan Izbrodin Anna Doroshkevich Mikhail Rampilov Alexey Elbaev German Ripp Geological institute Siberian Branch of the Russian Academy of SciencesRussia V.s.sobolev institute of Geology and Mineralogy Siberian Branch of the Russian Academy of SciencesRussia

This paper presents the results of geochronological(40Ar-39Ar,U-Pb sHRIMP Ⅱ),petrological and geochemical studies of the Late Paleozoic complexes of alkaline rocks(Zimovechinsky,Tuchinsky and Koma) located within the Vitim Plateau(the western part of the Mongol-Okhotsk Orogenic Belt).The rocks were formed at 310-280 *** is coeval with Late Paleozoic magmatism within the Central Asian Orogenic *** εNd(T) values show large variations from-2.1 to +3.3 as well as the initial sr(I) isotopic ratios from 0.7042 to 0.7138,that demonstrate strong isotopic heterogeneity of the magmatic *** geochemical characteristics of the rocks show pronounced positive Pb and negative Ti,Zr-Hf anomalies that can be explained by involvement of the subducted component in primary *** rocks intruded in a setting of extension at the active continental margin of the siberian Craton during subduction of Mongol-Okhotsk oceanic crust under the siberian Craton.

关键词： Nepheline-bearing and nepheline-free syenites Geochronological and isotope data Late paleozoic magmatism sources Central Asian orogenic belt

crustal structure of the Chuan-Dian Block Revealed by Deep seismic sounding and its Implications for the Outward Expansion of the East Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Acta Geologica sinica(English Edition) 2022年第6期96卷 1932-1944页

作者： XIONG Xiaosong WANG Guan LI Qiusheng LU Zhanwu GAO Rui FENG shaoying WU Guowei sinoProbe Center Chinese Academy of Geological SciencesBeijing 100037China Key Laboratory of Deep-earth Dynamics of the Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China school of earth science and Geological Engineering Sun Yat-Sen UniversityGuangzhou 510275China Geophysical Exploration Center Chinese Earthquake AdministrationZhengzhou 450002China

The Chuan-Dian Block(CDB)is located in the southeastern margin of the Tibetan Plateau,with a complex geological structure and active regional *** present tectonic condition with strong crustal deformation is closely related to the ongoing collision of the India and Eurasia plates since 65 *** study of the crustal structure of this area is key to revealing the evolution and deep geodynamics of the lateral collision zone of the Tibetan *** seismic sounding is the most efficient method with which to unravel the velocity structure of the whole *** the 1980s,19 deep seismic sounding profiles have been captured within the CDB *** this study,we systematically integrate the research results of the 19 profiles in this area,then image the 3D crustal velocity,by sampling with a 5 km spacing and 2D/3D Kriging *** results show the following.(1)The Moho depth in the study area deepens from 30 km in the south to 66 km in the north,whereas there is no apparent variation from west to *** Pn wave velocity is higher in stable tectonic units,such as 7.95 km/s in the Lanping-simao block and 7.94 km/s in the western margin of the Yangtze block,than in active or mobile tectonic units,such as 7.81 km/s in the Baoshan block,7.72 km/s in the Tengchong block and 7.82 km/s in the Zhongdian block.(2)The crustal nature of the Tengchong block,the northern Lanping-simao block and the Zhongdian block reflects a type of orogenic belt,having relatively strong tectonic activities,whereas the crustal nature of the central Lanping-simao block and the western margin of the Yangtze block represents a type of *** different features of the upper-middle crust velocity,Moho depth and Pn wave velocity to both sides of the Red River fault zone and the Xianshuihe fault zone,reflect that they are clearly ultra-crustal.(3)Based on the distribution of the low velocity zones in the crust,the crustal material of the Tibetan Plateau is flowing in a NW–sE direc

关键词： deep seismic sounding crustal structure outward expansion Chuan-Dian Block southeastern margin of the Tibetan Plateau

Zircon sHRIMP U-Pb Ages,Geochemistry and Nd-Hf Isotopes of~1.0 Ga A-Type Felsic Rocks in the southwestern Yangtze Block,south China:Petrogenesis and Tectonic Implications

在线全文

学校读者我要写书评

暂无评论

Journal of earth science 2023年第2期34卷 504-517页

作者： Ji-Biao Zhang Xiao-Zhong Ding Yan-Xue Liu institute of Geology Chinese Academy of Geological SciencesBeijing 100037China

The petrogenesis and tectonic affinity of Late Mesoproterozoic igneous rocks in the Yangtze Block are important to understand its tectonic evolution within the context of the Rodinia supercontinent’s ***,we report the sHRIMP zircon U-Pb ages,geochemistry,and Nd-Hf isotopic data for dacite from the Zegu Formation of the Dengxiangying Group in southwestern Yangtze *** crystallization age of the Zegu dacite is 1037 *** rocks have relatively high Ga,Zr,Hf,and HREE contents,as well as high(10000×Ga)/Al(2.7-2.9)and FeOt/MgO(3.8-10.5)ratios,showing a geochemical affinity of A-type ***,they are characterized by negativeεNd(t)(-3.6 to-7.5)and zirconεHf(t)values(-0.3 to-14.4),indicating that they likely generated via partial melting of an ancient continental crust *** tectonic discriminant diagrams showed that the Zegu dacites have high Y and Nb contents(plotted in the‘within-plate’magmatic rocks field).In conclusion,the geochemistry and isotopic data indicated that the 1037 Ma felsic volcanic rock in the Dengxiangying Group generated during an intra-plate rift basin along a passive *** work thus argues against a Grenvillian orogen’s existence in the Yangtze *** view of the subsequent Neoproterozoic subduction-related magmatism in the region,we suggest that the Yangtze Block might have been along the periphery of the Rodinia.

关键词： A-type granotoids zircon sHRIMP U-Pb dating intra-plate magmatism Late Mesoproterozoic southwestern Yangtze Block geochemistry

Multisphere Tectonics of the earth system

在线全文

学校读者我要写书评

暂无评论

Acta Geologica sinica(English Edition) 2022年第3期96卷 727-741页

作者： REN Jishun NIU Baogui XU Qinqin ZHAO Lei LIU Jianhui LI shan ZHU Junbin LIU Renyan institute of Geology Chinese Academy of Geological SciencesBeijing 100037China

The fundamental theoretical framework of the Multisphere Tectonics of the earth system is as follows:(1)It intends to extend the geotectonic studies from the crustal and lithospheric tectonics to the multisphere tectonics of the Ear th system as a whole.(2)The global dynamics driven by both the earth system and the cosmic celestial system:solar energy,multispheric interactions of the earth system and the combined effects of the motions of celestial bodies in the cosmos syste m are the driving forces of various geological processes.(3)The Continent-Ocean transformation theory:the continent and ocean are two opposite yet unified geological units,which can be transformed into each other;neither continent nor ocean wi ll survive forever;there is no one-way development of continental accretion or ocean extinction;the simple theory of one-way continental accretion is regarded as invalid.(4)The continental crust and mantle are characterized by multiple layers,with different layers liable to slide along the interfaces between them,but corroboration is needed that continents move as a who le or even drift freely.(5)The cyclic evolution theory:the development of earth’s tectonics is not a uniform change,but a spiral forward evolution,characterized by a combination of non-uniform,non-linear,gradual and catastrophic changes;different evolutionary stages(tectonic cycles)of earth have distinctive global tectonic patterns and characteristics,one tectonic mo del should not be applied to different tectonic cycles or evolutionary stages.(6)The structure and evolution of earth are asymmetric and heterogeneous,thus one tectonic model cannot be applied to different areas of the world.(7)The polycyclic evolution of the continental crust:the continental crust is formed by polycyclic tectonics and magmatism,rather than simply lateral or vertical accretion.(8)The role of deep faults:the deep fault zones cutting through different layers of the crus t a nd mantle usually play important roles

关键词： deep fault global dynamics cyclic evolution theory Multisphere Tectonics Continent-Ocean transformation theory earth system science

Petrogenesis and tectonic implications of the Early Cretaceous Dagushan adakitic porphyries in the Anshan area,North China Craton

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2022年第1期41卷 24-38页

作者： Xiaohui sun Haoshu Tang Yan Luan Key Laboratory of Western China’s Mineral Resources and Geological Engineering MOESchool of Earth Science and ResourcesChang’an UniversityXi'an 710054China state Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

The eastern part of the North China Craton suffered significant lithospheric thinning since the Mesozoic,and petrogenesis of the Dagushan adakitic diorite porphyries provides an excellent opportunity to investigate the lithospheric thinning mechanism and geodynamic *** zircon LA-ICP-Ms U–Pb geochronology reveals that the representative Dagushan adakitic porphyry was formed at 120.5±0.5 *** Dagushan diorite porphyries are characterized by the relatively high contents of siO_(2)(64.25–65.70 wt%),Al_(2) O_(3)(15.00–15.38 wt%),sr(333–491 ppm),low contents of Y(6.50–10.3 ppm),and Yb(0.57–0.85 ppm),and resultant high sr/Y(47–57)and La/Yb(37–55)ratios,exhibiting geochemical characteristics of typical ***,the relatively high Mg O contents(MgO=2.23–2.29 wt%)and Mg numbers(Mg^(#)-=54–56)of the Dagushan adakitic rocks imply that the pristine adakitic magma interacted with mantle ***,the zircon Hf isotopic signatures(εHf(t)=-19.0 to-28.0;TDM2=2378–2944 Ma)suggest an ancient lower crustal ***,it is proposed that the Dagushan adakitic rock was probably generated by partial melting of delaminated lower crust which was triggered by the Tan-Lu Fault Zone,and the interaction of pristine adakitic magma with mantle peridotite during the ascent finally generated the Dagushan high Mg^(#)adakitic *** is suggested that delamination was an important mechanism for lithospheric thinning of the NCC.

关键词： Diorite porphyry Adakite Lower crust Delamination NCC

P-T path of metamorphism and U-Pb monazite and zircon age of the Kitoy terrane: Implication for Neoarchean collision in sW siberian Craton

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2020年第6期11卷 1915-1934页

作者： Vasiliy P.sukhorukov Valentina B.savel’eva Yingde Jiang Zhiyong Li V.s.sobolev institute of Geology and Mineralogy sb RAs 3 Koptyuga Av.Novosibirsk630090Russia Novosibirsk state University 2 Pirogova St.Novosibirsk630090Russia institute of the earth crust sb RAs 128 Lermontova St.Irkutsk664033Russia state Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

The first data on P-T metamorphic conditions coupled with U-Pb monazite and zircon age obtained for the Neoarchean Kitoy granulite-gneiss terrane(sW siberian Craton).Alumina gneisses of the Kitoy terrane indicate two-staged metamorphic *** first stage of regional metamorphism(M1)occurred at high-amphibolite facies conditions at T=780-800℃ and P=8-9 *** second stage(M2)belongs to MT-HT/LP type of metamorphism with the wide temperature interval 600-750℃ and pressure 2-4 *** age peaks were established on the basis of U-Pb monazite and zircon dating in garnet-anthophyllite *** of them correspond to the Neoarchean age:the age of M1 falls into the interval of ca.2489-2496 Ma,the age of M2-ca.2446-2456 *** high-temperature metamorphism of the Kitoy block and nearly coeval granitoid magmatism can be an evidence for the Neoarchean collision in sW siberian craton.

关键词： siberian craton Neoarchean Kitoy terrane Metamorphism P-T path

Reworking of the Juvenile crust in the Late Mesozoic in North Qinling,Central China

在线全文

学校读者我要写书评

暂无评论

Journal of earth science 2022年第3期33卷 623-641页

作者： Ying-Yu Xue Haiyang Liu Zhiyi Wang Weidong sun Fukun Chen Center of Deep sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China school of earth and space sciences University of Science and Technology of ChinaHefei 230026China Center for Ocean Mega-science Chinese Academy of SciencesQingdao 266071China University of Chinese academy of sciences Beijing 100049China

The Qinling Orogen resulted from the collision between the North and south China blocks in the *** granitoids,ranging from the Triassic to the Cretaceous,are widely distributed in this orogen,and they provide excellent clues for understanding the crustal evolution and geodynamic evolution of the orogenic *** Triassic belt is mostly located in the south Qinling,whereas the Cretaceous belt is located mostly in the North *** Taibai complex pluton is located at the conjunction of the two *** we present a data set comprising zircon U-Pb dating and elemental and sr-Nd isotopic geochemistry for Late Mesozoic granite and microgranular enclaves(MME)exposed in the Taibai complex *** granite and MME yield concordant U-Pb zircon ages of 124 to 118 Ma,indicating that they were products of roughly simultaneous magmatism in the Late *** granite rocks are high-K,calc-alkaline,and weakly peraluminous in compositions,and they are characterized by enrichment in large ion lithophile elements(e.g.,Rb,Ba),depletion in high field strength elements(e.g.,Nb,Ta,Zr,Ti),and variable sr/Y ratios of 7.64 to *** MgO,Cr,and Ni contents imply that the magma(s)were essentially *** the granite and the MME show relative depletion in sr-Nd isotopic composition(initial ^(87)sr/^(86)sr of 0.7044 to 0.7067,initialε_(Nd) values of-3.4 to-2.6),suggesting that the magma(s)originated from juvenile crustal *** sr-Nd isotopic characteristics are significantly different from those of other Late Mesozoic granitoids exposed elsewhere in the Qinling orogenic belt,which formed from much older and enriched sources and with negligible contributions from mantle or juvenile *** propose a reworking event of the juvenile crust during the Late Mesozoic that was triggered by the tectonic extension and subsequent asthenospheric upwelling that occurred in eastern China.

关键词： Qinling Orogen Mesozoic granite crustal reworking Nd isotope geochemistry

Paleoclimatic record from Chumbur-Kosa section in sea of Azov region since Marine Isotope stage 11

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain science 2016年第6期13卷 985-999页

作者： LIANG Ye YANG Tai-bao Andrey Aleksevitch VELICHKO ZENG Biao sHI Pei-hong WANG Lin-dong HE Yi CHEN Jie CHEN Yu institute of Glaciology and Ecogeography College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China institute of Geography Russian Academy of SciencesMoscow 109027Russia

Loess–paleosol sequences preserve records of climatic change during the Quaternary,which is important for paleoclimate *** this study,a loess-palaeosol sequence from the ChumburKosa(CK) site in the sea of Azov region was investigated to reconstruct climatic variability during the Marine Isotope stage(MIs)11-MIs 1,using proxies of grain size(Gs),magnetic susceptibility(χlf and χfd(%)),carbonate content(Ca CO_3%) and soil *** results enabled formulation of a detailed description of the climatic characteristics related to each individual *** sequence indicates that the paleoclimate shifted progressively towards increasingly cooler,somewhat drier *** CK section may thus be ideal for reconstructing climatic conditions during the Middle and Late Pleistocene in the sea of Azov ***,the χlf value of paleosol s2 in the CK profile indicates different characteristics from the other paleosol layers,dilution of carbonate resulting from carbonate leaching in L2 may be the main reason for the decrease in magnetic ***,through simple analysis part of the environmental evolution process in the sea of Azov region and serbia during Middle and Late Pleistocene *** climate cycle expressed by χfd(%) and χlf variations show similar patterns,with rapidly alternating cold and warm ***,although the two areas had different climatic regimes,geographical settings,and loess source areas,both exhibited similar climate change trends since the MIs 11.

关键词：海洋环境氧同位素黄土-古土壤序列海地气候变化趋势管理信息系统碳酸盐含量黄沙

Genesis of the Gold Deposit in the Indus-Yarlung Tsangpo suture Zone,southern Tibet:Evidence from Geological and Geochemical Data

在线全文

学校读者我要写书评

暂无评论

Acta Geologica sinica(English Edition) 2017年第3期91卷 947-970页

作者： ZHANG Xiong DENG Xueguo YANG Zhusen HOU Zengqian ZHENG Yuanchuan LIU Yingchao ZHAO Xiaoyan XU Bo PEI Yingru ZHOU Jinsheng ZHAO Miao YUAN Jianfei school of earth sciences and Resources China University of GeosciencesBeijing MLR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological Sciences institute of Metallurgical Geology and Exploration Sichuan institute of Geology Chinese Academy of Geological Sciences ARC Centre of Excellence for Core to crust Fluid system(CCFs) and GEMOC Department Of Earth and Planetary SciencesMacquarie University

The Nianzha gold deposit, located in the central section of the Indus-Yarlung Tsangpo suture （IYs） zone in southern Tibet, is a large gold deposit （Au reserves of 25 tons with average grade of 3.08 g/t） controlled by a E-W striking fault that developed during the main stage of Indo-Asian collision （-65-41 Ma）. The main orebody is 1760 m long and 5.15 m thick, and occurs in a fracture zone bordered by Cretaceous diorite in the hanging wall to the north and the Renbu tectonic melange in the footwall to the south. High-grade mineralization occurs in a fracture zone between diorite and ultramafic rock in the Renbu tectonic melange. The wall-rock alteration is characterized by silicification in the fracture zone, serpentinization and the formation of talc and magnesite in the uitramafic unit, and chloritization and the formation of epidote and calcite in diorite. Quartz veins associated with Au mineralization can be divided into three stages. Fluid inclusion data indicate that the deposit formed from H20-NaCl-organic gas fluids that homogenize at temperatures of 203℃-347℃ and have salinities of 0.35wt%-17.17wt% NaCI equivalent. The quartz veins yield δ18Ofluid values of 0.15‰-10.45‰, low δDv-sMow values （-173%o to -96%o）, and the δ13C values of-17.6‰ to -4.7‰, indicating the ore-forming fluids were a mix of metamorphic and sedimentary orogenic fluids with the addition of some meteoric and mantle-derived fluids. The pyrite within the diorite has δ34sV-CDT values of -2.9‰-1.9‰（average -1.1‰）, 206pb/204pb values of 18.47- 18.64, 207pb/204pb values of 15.64-15.74, and 208pb/204pb values of 38.71-39.27, all of which are indicative of the derivation of s and other ore-forming elements from deep in the mantle. The presence of the Nianzha, Bangbu, and Mayum gold deposits within the IYs zone indicates that this area is highly prospective for large orogenic gold deposits. We identified three types of mineralization within the IYs, namely Bangbu-type accretionary, Mayum-type micro

关键词： geology gold mineralization Nianzha Deposit Indus-Yarlung Tsangpo suture zone Tibet

The high-resolution community velocity model V2.0 of southwest China,constructed by joint body and surface wave tomography of data recorded at temporary dense arrays

在线全文

学校读者我要写书评

暂无评论

中国科学:地球科学英文版 2023年第10期66卷 2368-2385页

作者： Ying LIU Ziye YU Zhiqi ZHANG Huajian YAO Weitao WANG Haijiang ZHANG Hongjian FANG Lihua FANG Laboratory of seismology and Physics of earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei230026China institute of Geophysics China Earthquake AdministrationBeijing100081China Mengcheng National Geophysical Observatory Mengcheng233500China CAs Center for Excellence in Comparative Planetology Mengcheng233500China school of earth sciences and Engineering Sun Yat-Sen UniversityZhuhai519080China

The sichuan-Yunnan area is located at the southeastern margin of the Tibetan Plateau,where tectonic movement is strong with deep and large faults distributed in a staggered manner,which results in strong seismic activities and severe earthquake *** the 21st century,several earthquakes of magnitude 7.0 or above occurred in this region,which have caused huge casualties and economic losses,especially the 2008 M_(s)8.0 Wenchuan *** present,earthquake monitoring and source parameter inversion,strong earthquake hazard analysis and disaster assessment are still the focus of seismological researches in the sichuan-Yunnan *** high-precision 3D community velocity models are fundamental for these *** this paper,by assembling seismic observations at permanent seismic stations and several temporary dense seismic arrays in this region,we obtained about 7.06 million body wave travel time data(including absolute and differential travel times)using a newly developed artificial intelligence body wave arrival time picking method and about 100,000 Rayleigh wave phase velocity dispersion data in the period range of 5-50 s from ambient noise cross-correlation *** on this abundant dataset,we obtained the three-dimensional high resolution V_p and V_(s)model in the crust and uppermost mantle of southwest(sW)China by adopting the joint body and surface wave travel time tomography method considering the topography effect starting from the first version of community velocity model in sW China(sWChina CVM-1.0).Compared to sWChina CVM-1.0,this newly determined velocity model has higher resolution and better data *** is accepted by the China seismic Experimental site as the second version of the community velocity model in sW China(sWChina CVM-2.0).The new model shows strong lateral heterogeneities in the shallow *** disconnected low velocity zones are observed in the middle to lower crust,which is located in the songpan-Ganzi block

关键词： southwest China Joint tomography Community velocity model seismic activity Fault zone