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Science China Earth Sciences 2002年第8期45卷 680-690页

作者：李江海张志强黄雄南 1. Department of Geology Peking University 100871 Beijing China 2. Institut fuer Geowissenschaften Universitaet Mainz 55099 Mainz Germany

The structural mapping and section study indicate that the “greenstone belts” in the southern to central parts of Hengshan were intensively sheared and transposed mafic dyke swarm, which originally intruded into the Neoarchean grey gneiss and high-pressure granulite terrain (HPGT). The HPGT is characterized by flat-dipping structures, to the south it became steep and was cut by the Dianmen mafic dyke swarm. After high-pressure granulite-facies metamorphic event, the mafic dyke swarm occurred, and was associated with the extensional setting and reworked by the late strike-slip shearing. The zircon age dating proves that the Dianmen mafic dyke swarm was emplaced during the period between 2499±4 Ma and 2512±3 Ma, followed by late tectonothermal reworking. The Dianmen mafic dyke swarm further documents the extensional episode in the central to northern parts of North China craton (NCC), providing the important constraint for the limit between Archean and Proterozoic and correlation between NCC and other cratonic blocks of the world.

关键词： mafic dyke swarm extensional tectonics isotopic age dating structural pattern craton limit between Ar-chean and Proterozoic.

Paleoproterozoic Nb-enriched meta-gabbros in the Quanji Massif,NW China:Implications for assembly of the Columbia supercontinent

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Geoscience Frontiers 2018年第2期9卷 577-590页

作者： Fan-Xi Liao Neng-Song Chen M.Santosh Qin-Yan Wang Song-Lin Gong Chuan He Hassan Abdelsalam Mustafa Institute of Geophysics and Geomatics China University of GeosciencesWuhan 430074China School of Earth Sciences China University of GeosciencesWuhan 430074China International Research Center for Geology and Resources along the Silk Roads China University of GeosciencesWuhan 430074China State Key Lab of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China Centre for Tectonics Resources and ExplorationDepartment of Earth SciencesUniversity of AdelaideSA 5005Australia School of Earth Sciences and Resources China University of Geosciences Beijing29 Xueyuan RoadBeijing 100083China School of Earth Sciences Zhejiang UniversityHangzhou310027China Three Gorges Geological Hazards Research Center Ministry of EducationChina University of GeosciencesWuhan 430074China Faculty of Science University of KordofanEL ObeidP.O 160Sudan

Diverse models have been proposed for the role of the Tarim craton within the Paleoproterozoic Columbia supercontinent assembly. Here we report a suite of-1.71 Ga Nb-enriched meta-gabbro lenses in the eastern Quanji Massif, within the Tarim craton in NW China. The meta-gabbroic rocks have Nb contents of 11.5-16.4 ppm with Nb/La ratios varying from 0.84 to 1.02((Nb/La)_N = 0.81-0.98) and Nb/U ratios from 38.0 to 47.2. They show low SiO_2(45.1-48.5 wt.%) and MgO(5.96-6.81 wt.%) and Mg#(Mg# = Mg/(Mg + Fe) = 43.5-47.7), high FeO^t(13.0-15.7 wt.%) and moderate Ti02(1.70-2.51 wt.%).with tholeiitic affinities. These rocks possess low fractionated REE patterns without obvious Eu anomalies(Eu/Eu~* = 0.87-1.02). Their primitive mantle-normalized elements patterns display significant Zr-Hf troughs, positive Nb anomalies, weak negative Ti and P anomalies, and high contents of Rb and Ba,resembling Nb-enriched basalts generated in arc-related tectonic settings. Their arc-like geochemical signatures together with whole rock εNd(t) values of 0.4-2.1 and corresponding old T_(DM)(2.22-2.37 Ga)as well as(^(143)Nd/^(144)Nd)_t and(^(87)Sr/^(86)Sr)t(t = 1712 Ma) values of 0.5104-0.5105 and 0.7030-0.7058,respectively, suggest that their precursor magma originated from mantle wedge peridotite metasomatised by subduction-derived melts. The results from our study reveal subduction along the eastern periphery of the Tarim craton and marginal outgrowth continuing to ~1.7 Ga within the Columbia supercontinent.

关键词： Nb-enriched gabbros Geochemistry Quanji Massif Tarim craton Columbia supercontinent

Attribution of the Langshan Tectonic Belt: Evidence from zircon U-Pb ages and Hf isotope compositions

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Geoscience Frontiers 2019年第2期10卷 539-551页

作者： Chuang Bao Yuelong Chen Xiangkun Zhu Junxiang Zhao Key Laboratory of Crustal Dynamics Institute of Crustal DynamicsCEA School of Earth Sciences and Resources China University of Geosciences Laboratory of Isotope Geology MLRInstitute of GeologyCAGS

This study describes a previously unidentified Neoproterozoic mafic dyke emplaced in the northern flank of the Langshan Tectonic Belt. This dyke intruded into the micaquartz schist of the Zhaertaishan Group, and yielded an age of 908 ± 8 Ma. The youngest U-Pb ages of micaquartz schist from the Zhaertaishan Group in the Langshan area were 1118 ± 33 Ma,1187 ± 3 Ma and 1189 ± 39 Ma,suggesting that the depositional age of the protolith of the schist was between 908 ± 8 Ma and 1118 ± 33 Ma. In addition, 436 U-Pb age data and 155 Lu-Hf isotopic data from six samples in the Langshan Tectonic Belt and one Permian greywacke from the Wuhai area show distinct differences between the northern and southern flanks of the Main Langshan area. The U-Pb ages of the northern flank are primarily Meso-Neoproterozoic; similar ages have not been identified in the southern flank to ***, two-stage Hf model ages of the northern flank feature three age peaks at ～900 Ma,～1700 Ma and ～2600 Ma; this differs from Hf model ages of the southern flank, which feature one strong age peak at ～2700 Ma. These results suggest that the northern and southern flanks of the Main Langshan area have different geochronologic characteristics and should be divided further. Based on the U-Pb ages and Hf model ages, the northern and southern flanks of the Main Langshan area are named the North and South Langshan Tectonic Belts. Comparison of the U-Pb age and two-stage Hf model age distributions from the North Langshan Tectonic Belt, South Langshan Tectonic Belt, Alxa Block and the North China craton(NCC) reveal that the North Langshan Tectonic Belt is similar to the Alxa Block and that the South Langshan Tectonic Belt is similar to the NCC. In addition, the zircon U-Pb age of 860 ±7 Ma commonly observed in the Alxa Block was detected in the Permian greywacke from the Wuhai area of the NCC, which suggests that the amalgamation of the North and South Langshan Tectonic belts(i.e.,the amalgamation of the Alxa

关键词： Langshan Tectonic Belt Attribution Alxa Block North China craton U-Pb Hf isotopic composition

Middle-Late Triassic sedimentation in the Helanshan tectonic belt: Constrain on the tectono-sedimentary evolution of the Ordos Basin, North China

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Geoscience Frontiers 2019年第1期10卷 213-227页

作者： Jiaopeng Sun Yunpeng Dong State Key Laboratory of Continental Dynamics Department of Geology Northwest University Department of Earth Sciences Western University

The Helanshan tectonic belt is located to the west of the Ordos Basin, and separates the Alxa(or Yinshan)Massif to the west from the Ordos block to the east. Triassic sedimentation in the Helanshan tectonic belt records important information about tectono-sedimentary process between the Alxa Massif and the Ordos block. Detailed geological mapping and investigation on the lithological package, sedimentary facies and paleocurrent orientation have been conducted on the Middle to Upper Triassic clastic rocks in the Helanshan tectonic belt. The succession is characterized by upward-fining sequence and comprises coarse grained alluvial-fluvial facies in the lower part as well as deltaic-lacustrine facies in the upper part. Based on detailed study and comparisons on the sedimentary sequence along various sections, the Middle to Upper Triassic strata have been revealed that show clear southeastward-deepening sedimentary differentiation and transgression from southwest to northeast, which are consistent with the southeastward flowing paleocurrent. These features indicate a southeastward-dipping paleogeography in the Helanshan tectonic belt, which was original western part of southeastward orientated fluviallacustrine system in the northwestern proto-Ordos Basin. Further to the east, the Triassic succession in the Ordos Basin displays gradually thickening and alluvial-fluvial system flowed from southeast to northwest, showing a huge thick sedimentary wedge in the western basin margin. Together with the Late Permiane Early Triassic closure of the Paleo-Asian Ocean to the north, the Late Triassic extensional structures and diabase dykes in the Helanshan tectonic belt, all the above sedimentary features could be mostly interpreted as records of an extensional basin correlated to post-collisional collapse of the Central Asian Orogenic Belt.

关键词： Triassic sedimentation Half graben Helanshan tectonic belt Alxa Massif North China craton

Geochemistry of the high-Mg andesites at Zhangwu, western Liaoning: Implication for delamination of newly formed lower crust

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Science China Earth Sciences 2007年第12期50卷 1773-1786页

作者： HUANG Hua1,GAO Shan1,2,HU ZhaoChu1,LIU XiaoMing2 & YUAN HongLing2 1 State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China 2 State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China 1. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China 2. State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an 710069 China

Ten volcanic samples at Zhangwu,western Liaoning Province,North China were selected for a sys-tematic geochemical,mineralogical and geochronological study,which provides an opportunity to ex-plore the interaction between the continental crust and mantle beneath the north margin of the North China *** one basalt sample(SiO2= 50.23%),the other nine samples are andesitic with SiO2 contents ranging from 53% to 59%.They have relatively high MgO(3.4%―6.1%,Mg#=50―64) and Ni and Cr contents(Ni 27×10?6―197×10?6,Cr 51×10?6―478×10?6).Other geochemical characteristics of Zhangwu high-Mg andesites(HMAs) include strong fractionation of light rare earth elements(LREE) from heavy rare earth elements(HREE),and Sr from Y,with La/Yb greater than 15,and high Sr/Y(34― 115).Zircons of andesite YX270 yield three age groups with no Precambrian age,which precludes ori-gin of the Zhangwu HMAs from the partial melting of the Precambrian *** oldest age group peaking at 253 Ma is interpreted to represent the collision of the Siberia block and the North China block,resulting in formation of the Central Asian orogenic belt by closure of the Mongol-Okhotsk *** intermediate age group corresponds to the basalt underplating which caused the wide-spread coeval granitoids in the North China craton with a peak 206Pb/238U age of 172 *** youngest age group gives a 206Pb/238U age of 126±2 Ma,which is interpreted as the eruption age of the Zhangwu *** high 87Sr/86Sri(126 Ma)>0.706 and low εNd(t)= ?6.36―?13.99 of the Zhangwu HMAs are distinct from slab *** common presence of reversely zoned clinopyroxene phenocrysts in the Zhangwu HMAs argues against the origin of the Zhangwu HMAs either from melting of the water saturated mantle or melting of the lower *** light of the evidence mentioned above,the envisaged scenario for the formation of the Zhangwu HMAs is related to the basaltic underplating at the base of the crust,which led to the thickening of the lower crust and

关键词： Zhangwu HMAs, basalt underplating, newly formed lower crust, delamination, North China craton

Tonian Tectonic-Strata Regions and their Geological Significance in China

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Acta Geologica Sinica(English Edition) 2020年第4期94卷 914-941页

作者： XU Yadong ZHANG Kexin HE Weihong YU Yang KOU Xiaohu SONG Bowen LUO Mansheng WANG Lijun MA Zhongjie YANG Fengli Hubei Key Laboratory of Critical Zone Evolution School of Earth SciencesChina University of GeosciencesWuhan 430074China Central South China Innovation Center for Geosciences Wuhan Center of the Chinese Geological SurveyWuhan 430074China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China Center of Global Tectonic China University of GeosciencesWuhan 430074China Institute of Geological Survey China University of GeosciencesWuhan 430074China State Key Laboratory of Marine Geology School of Ocean and Earth ScienceTongji UniversityShanghai 200092China

The continent of China developed through the coalescence of three major cratons(North China, Tarim and Yangtze) and continental micro-blocks through the processes of oceanic crust disappearance and acceretionary-collision of continental crusts. The strata of the Chinese continental landmass are subdivided into 12 tectonic-strata regions. Based on the composition of geological features among the three main cratons, continental micro-blocks and other major global cratons, their affinities can be preliminarily deduced during the Tonian period, using evidence from sedimentary successions, paleobiogeography, tectonic and magmatic events. The Yangtze and Tarim cratons show that they have close affinities during the assembly-dispersal milestone of the Rodinia Supercontinent. The sedimentary record and magmatic age populations in the blocks suggest that there was a widespread, intensive magmatic event that resulted from a subduction process during ~1000–820 Ma, related to continental rifting around the Yangtze and Tarim cratons. However, they differ greatly from the North China craton. The continental micro-blocks in the Panthalassic Ocean could have some missing connection with the North China craton that persisted until the Middle-Late Devonian. In contrast, the Alxa Block showed a strong affinity with the Tarim craton. The revised Tonian paleogeography of the Rodinia Supercontinent is a good demonstration of how to show the relationship between the main cratons and the continental micro-blocks.

关键词： Sedimentary paleogeography Tonian craton micro-block

Electron Probe Microanalysis of Monazite and Its Applications to U-Th-Pb Dating of Geological Samples

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Journal of Earth Science 2019年第5期30卷 952-963页

作者： Wenbin Ning Junpeng Wang Deng Xiao Fenfang Li Bo Huang Dong Fu State Key Laboratory of Geological Processes and Mineral Resources Hubei Key Laboratory of Critical Zone Evolution Center for Global Tectonics School of Earth Sciences China University of Geosciences

Electron probe microanalysis(EPMA) dating of monazite has been developed over decades. However, limited by the detectability and analytical sensitivity of dating-related elements(Th, Pb, U and Y), the EPMA dating has been restricted to geological research. In this study, various probe currents, beam diameters and counting times have been utilized on a JEOL JXA-8230 electron microprobe to determine the optimal experimental conditions for measuring Th, Pb, U and Y in monazite. The optimal conditions are:(1) accelerating voltage is 15 k V;(2) probe current is 100 n A;(3) beam diameter is 1 μm;(4) the peak and background counting time of U and Pb are 200 and 100 s;and(5) the peak and background counting time of Th and Y are 100 and 50 s. We apply this method to monazite from garnet-bearing biotite gneiss in the Zanhuang area of the Central Orogenic Belt of the North China craton. The Pb O-Th O2* isochron age calculated by EPMA data is 1 812±17 Ma(MSWD=2.06), which is similar to the weighted mean 207 Pb/206 Pb age(1 805±12 Ma, MSWD=1.07) obtained by LA-ICP-MS. This study suggests that EPMA dating of monazite as a powerful dating technique can be widely used in geochronological study.

关键词： monazite EPMA dating garnet-bearing biotite gneiss Zanhuang area North China craton geochemistry

P-wave tomographic images beneath southeastern Tibet:Investigating the mechanism of the 2008 Wenchuan earthquake

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Science China Earth Sciences 2010年第9期53卷 1252-1259页

作者： WEI Wei SUN RuoMei SHI YaoLin Laboratory of Computational Geodynamics Graduate University of Chinese Academy of SciencesBeijing 100049China Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China

We used 71670 P-wave arrival times from 3594 earthquakes recorded by the Sichuan and Yunnan seismic networks to determine the three-dimensional P-wave velocity structure in the crust and uppermost mantle beneath the southeastern Tibetan Plateau. Our results show that prominent low P-wave velocity (low-Vp) anomalies exist in the midto lower crust of the Song- pan-Ganze and Sichuan-Yunnan blocks. In contrast, a high P-wave velocity (high-Vp) anomaly is resolved in the middle and lower crust beneath the Sichuan Basin. Our tomographic results provide seismic evidence for a dynamic model of lower crustal flow. Ongoing lower crustal flow beneath the central and eastern Tibetan Plateau abuts against the mechanically strong Si- chuan Basin resulting in accumulated strain in the Longmen Shan region. When a critical accumulation of strain energy was reached, its sudden release led to the occurrence of 2008 Wenchuan earthquake. Pronounced low-Vp anomalies are observed in the uppermost mantle in the region south of ~26°N. Combining these results with shear-wave splitting investigations, we suggest that the flow of asthenospheric material has impacted the velocity structure of the uppermost mantle and caused the thinning of the southwestern Yangtze craton.

关键词： seismic tomography Sichuan-Yunnan Block Wenchuan earthquake Longmenshan fault Yangtze craton

Nd isotopic compositions of the Tethyan Himalayan Sequence in southeastern Tibet

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Science China Earth Sciences 2008年第9期51卷 1306-1316页

作者： DAI JinGen YIN An LIU WenCan WANG ChengShan State Key Laboratory of Geological Processes and Mineral Resources Research Center for Tibetan Plateau Geology and School of GeosciencesChina University of GeosciencesBeijing 100083China Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics University of CaliforniaLos AngelesCA 90095-1567USA

The Himalayan orogen consists of three major lithologic units that are separated by two major north-dipping faults: the Lesser Himalayan Sequence (LHS) below the Main Central Thrust (MCT), the Greater Himalayan Crystalline Complex (GHC) above the MCT, and the Tethyan Himalayan Sequence (THS) juxtaposed by the South Tibet Detachment fault (STD) over the GHC. Due to widespread meta-morphism and intense deformation, differentiating the above three lithologic units is often difficult. This problem has been overcome by the use of Sm-Nd isotopic analysis. The previous studies suggested that the LHS can be clearly distinguished from the GHC and THS by their Nd isotope compositions. However, the lack of detailed and systematic Sm-Nd isotopic studies of the THS across the Himalaya in general has made differentiation of this unit from the nearby GHC impossible, as the two appear to share overlapping Nd compositions and model ages. To address this problem, we systematically sam-pled and analyzed Nd isotopes of the THS in southeastern Tibet directly north of Bhutan. Our study identifies two distinctive fields in a εNd -TDM plot. The first is defined by the εNd(210 Ma) values of -3.45 to -7.34 and TDM values of 1.15 to 1.29 Ga from a Late Triassic turbidite sequence, which are broadly similar to those obtained from the Lhasa block. The second field is derived from the Early Cretaceous meta-sedimentary rocks with εNd(130 Ma) values from -15.24 to -16.61 and TDM values from 1.63 to 2.00 Ga; these values are similar to those obtained from the Greater Himalayan Crystalline Complex in Bhutan directly south of our sampling traverse, which has εNd(130 Ma) values of -10.89 to -16.32 and Nd model ages (TDM) of 1.73 to 2.20 Ga. From the above observations, we suggest that the Late Triassic strata of the southeast Tibetan THS were derived from the Lhasa block in the north, while the Early Cretaceous strata of the THS were derived from a source similar to the High Himalayan Crystalline Comp

关键词： Himalayan orogen Sm-Nd isotopic systematics Greater Himalayan Crystalline Complex Tethyan Himalaya Sequence Lhasa ter- rane Indian craton

Structural characteristics and petroliferous features of Tarim Basin

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Chinese Science Bulletin 2002年第S1期47卷 1-11页

作者： JIA Chengzao~1 & WEI Guoqi~2 1. PetroChina Company Limited, Beijing 100011, China 2. Langfang Branch of Research Institute of Petroleum Exploration & Development, PetroChina, Langfang 065007, China 1. PetroChina Company Limited 100011 Beijing China 2. Langfang Branch of Research Institute of Petroleum Exploration & Development PetroChina 065007 Langfang China

Using the modern tectonic geology theories andmethods such as the plate tectonic analysis, the paleo-struc-ture analysis, the structural-Iithofacies analysis, and the faultrelated fold and petroleum system, and combining with theseismic data, well drilling data and the circumferential fieldgeology, study on the structural characteristics and petro-leum prospect in the Tarim Basin has been carried out. Re-sults show that the Tarim Basin is a large superimpositionand combination basin with continental crustal basement,composed of a Paleozoic craton and Meso-Cenozoic forelandbasins. The characteristics of the basin are: the kernel partof the basin is the marine facies Paleozoic craton, superim-posed 4 continental facies foreland basins. Though the scaleof the paleozoic craton of the Tarim Basin is relatively small,the structure is steady. The petroleum prospect of the Paleo-zoic craton is: multiphase pool-generation and accumulationcontrolled by ancient uplift. The Meso-Cenozoic forelandbasins in the Tarim Basin, which are distributed on the era-tonic circumference and are a long-term subsidence, turnedinto rejuvenated foreland basins after the Meso-Cenozoicperiod. The petroleum prospects are: coal-bed generatinghydrocarbon, abundant natural gas, pool-generation in laterand recent periods, the oil and gas distribution controlled bythe foreland thrust belt. The structural characteristics ofTarim provide it with a superimposition and combinationpetroleum system of multiple resources, multiple reservoirsand multiphase pool-generation. The oil and gas explorationprospect covers two large fields: the Paleozoic craton and theMeso-Cenozoic foreland thrust belt.

关键词： Tarim superimposition and combination basin craton foreland basin superimposition and combination petroleum system.