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Uranium distribution in the lacustrine calcareous clastic-evaporite sequence in the western Qaidam Basin,and implications for U behavior in concentration of closed water

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Acta Geologica Sinica(English Edition) 2014年第S1期88卷 168-169页

作者： YANG Yibo FANG Xiaomin LI Minghui APPEL Erwin ZHANG Weilin LIU Xiaoming key laboratory of continental collision and plateau uplift Institute of Tibetan Plateau Research Chinese Academy of Sciences Paleoenvironmental Dynamics Group Institute of Geosciences Goethe University Frankfurt Altenhferallee 1

Uranium(U)provides especially useful information for reconstructing paleoredox conditions due to its unique geochemical properties and behavior in supergene *** proxy potential under suboxic-oxic

关键词： Uranium Paleoredox conditions Lacustrine sediments Evaporite Qaidam Basin

Distinctive melt activity and chromite mineralization in Luobusa and Purang ophiolites, southern Tibet: constraints from trace element compositions of chromite and olivine

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Science Bulletin 2019年第2期64卷 108-121页

作者： Benxun Su Meifu Zhou Jiejun Jing Paul T. Robinson Chen Chen Yan Xiao Xia Liu Rendeng Shi Davide Lenaz Yan Hu key laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Sciences Institutions of Earth Science Chinese Academy of Sciences Department of Earth Sciences The University of Hong Kong State key laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences key laboratory of continental collision and plateau uplift Institute of Tibetan Plateau Research Chinese Academy of Sciences Department of Mathematics and Geosciences University of Trieste Department of Earth and Space Sciences University of Washington

To investigate the factors controlling the mineralization in ophiolites we systematically compared the petrology and mineral compositions of the harzburgites/lherzolites, dunites and chromitites in the Luobusa and Purang ophiolites. Generally, the petrological features and trace element compositions of chromite and olivine in peridotite and chromitite are distinctly different between the two *** Luobusa, boninitic melts are inferred to have interacted with the harzburgites and modified the distributions of some trace elements(e.g., Ni, Mn and V) in chromite and olivine. The subsequently formed dunites and chromitites experienced significant elemental exchange. In contrast, the Purang ophiolite contains a wider range of chromitite compositions and records diverse melt activities, such as the growth of relatively abundant secondary clinopyroxene. The metasomatic melts were enriched in Al and depleted in Si, Na and highly incompatible trace elements(e.g., Nb, Zr). Such melts resemble MORBlike melts proposed in the literature but are assumed to be more hydrous than typical MORB because of presence of hydrous minerals. The parental magmas of the Purang dunites and intermediate chromitites are inferred to be compositionally intermediate between boninitic and MORB-like melts. In addition,the more refractory nature of the Luobusa harzburgites facilitated a high Cr concentration gradient with the interacting melts, making it easier to increase Cr in the melts. Crystallization of clinopyroxene and amphibole in the Purang ophiolite accommodated significant amounts of Cr and water, respectively,and negatively affected Cr concentration and chromite crystallization. The concentration of chromite to form chromitites requires the presence of focused melt channels.

关键词： Chromite Olivine Ophiolite Trace element Tibet

The Late Cretaceous source-to-sink system at the eastern margin of the Tibetan plateau:Insights from the provenance of the Lanping Basin

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Geoscience Frontiers 2021年第3期12卷 279-295页

作者： Licheng Wang Lijian Shen Chenglin Liu Ke Chen Lin Ding Chengshan Wang CAS Center for Excellence in Tibetan plateau Earth Sciences Key Laboratory of Continental Collision and Plateau UpliftInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China MNR key laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China Yunnan Geological Survey Kunming 650051China School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China

The surface uplift of the Tibetan plateau(TP)and its geomorphology evolution has triggered aridification of Asia's interior and drainage development at the eastern margin of the ***,how the pre-Cenozoic early growth histories of the TP impact the drainage system and climate is poorly *** Late Mesozoic Lacustrine evaporite-bearing basins on the eastern margin of the TP record significant information on the uplift of the source terranes,source-to-sink system development and climate *** this study,we presented detrital zircon U-Pb ages from the Upper Cretaceous Yunlong Formation in the Lanping Basin,as well as Hf isotopic,petrographic,direct statistical,and multidimensional scaling analyses,and use them to characterize the provenance and reconstruct the drainage *** of the samples have five major age peaks at 200-290 Ma,400-490 Ma,750-1000 Ma,1750-1950 Ma,and 2400-2600 Ma with mostly negativeε_(Hf)(t)values(81%).We infer the sediments are primarily derived from recycled sediments of the Songpan-Garze terrane,and partly from the Sichuan Basin and the Southern Qiangtang terrane,as well as the exposed magmatic rocks of the Yidun Arc and SongpanGarze *** provenance features of the contemporaneous sediments from the Sichuan,Xichang,Chuxiong,and Simao basins indicate a complex hierarchical drainage pattern on the eastern margin of the TP during the Late *** hierarchical drainage system exhibits a complete gradational cycle of lake-basin types from overfilled freshwater Sichuan Basin through balanced fill saline Xichang Basin and underfilled hypersaline Chuxiong,Lanping,Simao,and Khorat plateau basins from proximal to *** early growth of the TP primarily controlled the drainage and lake-basin evolution by not only causing the uplift and exhumation of the source areas and providing large amounts of clastic material to the proximal sub-drainage areas but also intensifying the aridity and deposition of evaporites.

关键词： Detrital Zircons Drainage Late Cretaceous Source-to-sink Lacustrine Basin Tibetan plateau

Granitic Magmatism in Eastern Tethys Domain(Western China) and their Geodynamic Implications

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Acta Geologica Sinica(English Edition) 2022年第2期96卷 401-415页

作者： LAI Shaocong ZHU Renzhi QIN Jiangfeng ZHAO Shaowei ZHU Yu State key laboratory of continental Dynamics Department of GeologyNorthwest UniversityXi’an 710069China

Western China locates in the eastern section of the Tethys domain, granitic rocks in this region with variable formation ages and geochemistry record key information about the crust-mantle structure and thermal evolution during the convergent process of Tethys. In this study, we focus on some crucial granitic magmatism in the western Yangtze, Qinling orogen, and western Sanjiang tectonic belt, where magma sequence in the convergent orogenic belt can provide important information about the crust-mantle structure, thermal condition and melting regime that related to the evolution processes from Pre-to Neo-Tethys. At first, we show some features of Pre-Tethyan magmatism, such as Neoproterozoic magmatism(ca. 870–740 Ma) in the western margin of the Yangtze Block were induced by the assembly and breakup of the Rodinia supercontinent. The complication of voluminous Neoproterozoic igneous rocks indicated that the western Yangtze Block underwent the thermodynamic evolution from hot mantle-cold crust stage(ca. 870–850 Ma) to hot mantle and crust stage(ca. 850–740 Ma). The Neoproterozoic mantle sources beneath the western Yangtze Block were progressively metasomatized by subduction-related compositions from slab fluids(initial at ca. 870 Ma), sediment melts(initial at ca. 850 Ma), to oceanic slab melts(initial at ca. 825–820 Ma) during the persistent subduction process. Secondly, the early Paleozoic magmatism can be well related to three distinctive stages(variable interaction of mantle-crust to crustal melting to variable sources) from an Andeans-type continental margin to collision to extension in response to the evolution of ProtoTethys and final assembly of Gondwana continent. Thirdly, the Paleo-Tethys magmatism, Triassic granites in the Qinling orogenic display identical formation ages and Lu-Hf isotopic compositions with the related mafic enclaves, indicate a coeval melting event of lower continental crust and mantle lithosphere in the Triassic convergent process and a

关键词： granitic magmatism geodynamic western China eastern Tethys

Paleozoic Tectonic Switch in the North Qinling Orogenic Belt:Constraints from the Paleozoic Granites from the Northern Qinling Migmatite Terrane

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Acta Geologica Sinica(English Edition) 2023年第3期97卷 695-706页

作者： QIN Jiangfeng LAI Shaocong LONG Xiaoping State key laboratory of continental Dynamics Department of GeologyNorthwest UniversityXi'an 710069China

The variations in source rocks and melting conditions of granites can provide essential clues for the crustal magmatic response in orogenic *** on geochronology,whole-rock and mineral chemistry,this paper reveals two different granites in the Northern Qinling migmatite complex,which reveal obvious differences in source region and melting *** older granodiorite(402±0.8 Ma)displays typical Na-rich adakite affinity,i.e.,high Na_(2)O/K_(2)O(2.04 to 2.64)and Sr/Y(96 to 117)ratios,they have relative evolved isotopic compositions(ε_(Nd)(t)=-0.52 to-0.04;zirconε_(Hf)(t)=-0.06 to+7.78).The younger leucogranite(371±2 Ma)displays higher SiO_(2)(72.32 to 73.45 wt%),lower(TFeO+MgO+CaO+TiO_(2))contents(collision process between the South Qinling and North China Craton(NCC)in Devonian era.

关键词： Qinling zircon Paleozoic

U-Pb Zircon Ages and Geochemistry of the Metasedimentary Rocks from the Foping Area in the South Qinling Belt:Evidence for Early Devonian Amalgamation between North China and South China Blocks

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Journal of Earth Science 2023年第4期34卷 1112-1127页

作者： Ruiying Zhang Wenhao Ao Yan Zhao State key laboratory of continental Dynamics Department of GeologyNorthwest UniversityXi􀆳an 710069China

The provenance and tectonic implications of Late Paleozoic sedimentary rocks in the South Qinling Belt(SQB) provide important clues for understanding the timing and mechanism of the collision between North China Block(NCB) and South China Block(SCB).Here we report new LAICP-MS zircon U-Pb ages and geochemical composition of metasedimentary rocks from the Foping area in the *** results indicate that the depositional age of the Wenquan Group can be limited to the Early Devonian by the youngest U-Pb age of 398 Ma,whereas those of the quartz schist from the Changjiaoba Group could be constrained after the Carboniferous by the youngest206Pb/238U peak age of 306 ***,much of the previously-assumed “Neoarchaean or Paleoproterozoic” strata,including the Wenquan and Changjiaoba groups,were actually deposited in the Late *** on analysis and comparison of the detrital zircon ages of the Devonian tectonic units in the SQB,we found that most prominent peak ages of detrital zircons from metasedimentary rocks in the Foping area shared similar characteristics with *** mainly derived from the North Qinling Belt and South Qinling Belt-Yangtze Block,with a minor source probably from the North China Block,implying that the Shangdan Ocean between NCB and SCB had closed in the Early *** with regional geological background and geochemical data,we inferred that these Devonian strata formed in the foreland basin after the amalgamation of the North China Block and South China Block.

关键词： detrital zircon geochronology geochemistry Devonian sedimentation South Qinling belt forelandbasin geochemistry.

Paleogeography control of Indian monsoon intensification and expansion at 41 Ma

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Science Bulletin 2021年第22期66卷 2320-2328,M0004页

作者： Xiaomin Fang Maodu Yan Weilin Zhang Junsheng Nie Wenxia Han Fuli Wu Chunhui Song Tao Zhang Jinbo Zan Yongpeng Yang State key laboratory of Tibetan plateau Earth System Resources and EnvironmentInstitute of Tibetan Plateau Research(TPESRE)Chinese Academy of SciencesBeijing 100101China key laboratory of continental collision and plateau uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China key laboratory of Western China’s Environments of Ministry of Education Lanzhou UniversityLanzhou 730000China Shandong Provincial key laboratory of Water and Soil Conservation&Environmental Protection School of Resource and Environmental SciencesLinyi UniversityLinyi 276000China School of Earth Sciences&key laboratory of Western China’s Mineral Resources of Gansu Province Lanzhou UniversityLanzhou 730000China

As a crucial part of the Asian monsoon stretching from tropical India to temperate East Asia, the Indian monsoon(IM) contributes predominant precipitation over Asian continent. However, our understanding of IM’s onset, development and the underlying driving mechanisms is limited. Increasing evidence indicates that the IM began in the Eocene or even the Paleocene and was unexceptionally linked to the early rise of the Tibetan plateau(TP). These were challenged by the heterogeneous and diachronous uplift of the TP and all the reported records were confined to tropical zone under tropical monsoon driven by the Intertropical Convergence Zone(ITCZ) that is irrelevant to the TP. Therefore, reliable paleoclimatic records from the extra-tropical IM region is crucial to reveal how the tropical IM expanded to subtropical and temperate zones and what driving factors might be related to it. Here we present robust Eocene paleoenvironmental records from central Yunnan(~26°N) in subtropical East Asia. The multiproxy results of two sites demonstrate a consistent sudden switch from a dry environment in the early Eocene to a seasonally wet one at 41 Ma, suggesting a jump of the tropical IM to the southern subtropical zone at 41 *** full collision of India with Asia, and the resulting changes in paleogeography at 41 Ma(closure of the Neotethys sea, retreat of the Paratethys seas, fast northward movement of the southern margin of the TP and rise of the central TP), aided by synchronous Antarctic cooling, might have worked together to drive the IM enhancement and northward expansion.

关键词： Asia paleogeography Indian tropical monsoon Eocene paleoenvironment Subtropical monsoon onset Driven factors and forcings

Mio-Pleistocene minerals of core SG-1b in the Qaidam Basin(NE Tibetan plateau): implications for climate and uplift

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Mio-Pleistocene minerals of core SG-1b in the Qaidam Basin(N...

Topsoil C/N ratios in the Qilian Mountains area: implications for the use of subaqueous sediment C/N ratios in paleo-environmental reconstructions to indicate organic sources

2015中国地球科学联合学术年会

作者： Minghui Li key laboratory of continental collision and plateau uplift Institute of Tibetan Plateau Research CAS

Strong uplift of Tibetan plateau had great effect on sediments in Qaidam Basin since Late ***,we know little about the process of how the minerals response to the uplifting due to a scarcity of precisely dated continuous sediment records in the *** we understand this process by providing a nearly 6-Ma(7.3-1.6 Ma)high-resolution of minerals from a 723 m borehole SG-1b in western Qaidam Basin.

关键词： Mio-Pleistocene minerals of core SG-1b in the Qaidam Basin NE Tibetan plateau implications for climate and uplift

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Topsoil C/N ratios in the Qilian Mountains area: implication...