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Late Cretaceous High-Sr/Y Granitic Rocks in the Eastern Tibetan Plateau: Crustal Thickening During Continental Collision

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Acta Geologica Sinica(English Edition) 2020年第S1期94卷 19-20页

作者： HU Peiyuan ZHAI Qingguo WANG Jun key laboratory of deep-earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China

High-Sr/Y granitic rocks,characterized by intermediate–high SiO2 contents(>56 wt.%),high La/Yb ratios(>20),and low Y(<18 ppm)and Yb(<1.9 ppm)contents,have drawn much attention from geologists in the past *** were ori... 详细信息

High-Sr/Y granitic rocks,characterized by intermediate–high SiO2 contents(>56 wt.%),high La/Yb ratios(>20),and low Y(earth’s *** Tibetan plateau,generally considered as an archetype of collisional orogen,was formed by the successive accretion of different tectonic terranes to the southern margin of the Eurasia plates since the Early ***,the Tibetan plateau comprises several W–E trending terranes(the Kunlun,North Qiangtang,South Qiangtang,and Lhasa terranes)and northernmost India(the Himalaya region).These terranes have undergone significant crustal thickening during the continental collision *** crustal thickness of the Tibetan plateau is asymmetric,being thickest under the Lhasa terrane and thinning more gradually towards the north than to the *** south to north,the crustal thickness increases from^50 km in the Himalaya region,to^70–80 km under the Lhasa terrane,and decreases to^65 km under the North and South Qiangtang terranes and^55 km beneath the Kunlun *** present crustal thickness of the Tibetan plateau has generally been attributed to the Cenozoic collision between the Indian and Eurasian plates and the subsequent intracontinental convergences since^55 ***,doubts were raised about this interpretion in the past few *** example,recent studies indicated the crust of the Lhasa terrane had been significantly thickened during ca.140–130 Ma in

关键词： Tibetan plateau south Qiangtang terrane high-Sr/Y granitic rocks petrogenesis

The optical and molecular signatures of DOM under the eutrophication status in a shallow,semi-enclosed coastal bay in southeast China

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Science China earth Sciences 2021年第7期64卷 1090-1104页

作者： Chen ZHAO Yuping ZHOU Yu PANG Yanzhen ZHANG Wei HUANG Yuntao WANG Ding HE key laboratory of Geoscience Big Data and deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhou 310027China State key laboratory of Satellite Ocean Environment dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310027China

We applied stable carbon isotopes,ultraviolet-visible absorption(UV-Vis),fluorescence excitation-emission matrices spectroscopy(EEMs),and Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)to investigate the chemical composition and sources of the dissolved organic matter(DOM)in both the water column and pore water in Xiangshan Bay,a representative semi-enclosed and eutrophic bay in Zhejiang Province,*** protein-like fluorescent component(C1)and two humic-like fluorescent components(C2 and C3)were identified by PARAFAC *** concentration of dissolved organic carbon(DOC),the relative intensities of C2,C3,and black carbon-like compounds are all negatively correlated with salinity,indicating that there is a dilution effect of terrestrial signals by seawater in Xiangshan *** differences in light penetration ability of Xiangshan Bay cause different degrees of photo-degradation,which may play an important role in the transformation of organic matter in Xiangshan *** weak correlation between the C1 fluorescent component and salinity indicates that autochthonous sources cannot dominate the protein-like FDOM in the Xiangshan Bay drainage *** sources(such as anthropogenic inputs and release of pore water)also affect the distribution of the protein-like fluorescent component under eutrophication *** relative proportion of the protein-like fluorescent component in Xiangshan Bay is on a medium level in China and anthropogenic inputs may be a significant source of DOM in coastal bays.

关键词： Xiangshan Bay Dissolved organic matter Optical properties Molecular composition Transporting and processing

Five Years of IGCP 649 Project-Diamonds and Recycled Mantle

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Acta Geologica Sinica(English Edition) 2020年第S1期94卷 1-3页

作者： YANG Jingsui SHEN Tingting ZHANG Cong QIU Tian key laboratory of deep-earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China School of earth Sciences and Engineering Nanjing UniversityNanjing 210023China

The IGCP-649 project―Diamonds and Recycled Mantle‖is an International Geosciences Program sponsored by UNESCO and IUGS in March *** is a global research project,aimed to carry out extensive and systematic research on peridotites,chromitites and related materials such as diamond,moissanite and other unusual minerals,from different ophiolites in global orogenic belts,for understanding the formation and origin of deepmantle minerals in oceanic lithosphere,the origin of carbon for the ophiolite-hosted diamonds,the evolution of earth’s mantle and the dynamic process of ophiolite *** IGCP-649 project(2015–2019)is undertaken by the Center for Advanced Research on the Mantle(CARMA),leading by *** Yang,Institute of Geology,Chinese Academy of Geological Sciences,and cooperated by an international team of researchers including *** Dilek of Miami University(USA),*** L Griffin of Macquarie University(Australia),*** *** of Dalhousie University(Canada),*** Milushi of Polytechnic University of Tirana(Albania),and *** Metwaly Abu Anbar of Tanta University(Egypt).

关键词： IGCP mantle minerals

Destruction of the Northern Margin of the North China Craton in Mid-Late Triassic: Evidence from Asthenosphere-derived Mafic Enclaves in the Jiefangyingzi Granitic Pluton from the Chifeng Area, Southern Inner Mongolia

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Acta Geologica Sinica(English Edition) 2020年第4期94卷 1071-1092页

作者： LIU Jianfeng LI Jinyi CHI Xiaoguo ZHENG Peixi HU Zhaochu ZHANG Xiaowei key laboratory of deep-earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China key laboratory of Mineral resources Evaluation in Northeast Asia Ministry of Land and ResourcesChangchun 130061China College of earth Science Jilin UniversityChangchun 130061China State key laboratory of Geological Processes and Mineral resources China University of GeosciencesWuhan 430074China

The petrology, geochronology and geochemistry of the mafic enclaves in the Mid-Late Triassic Jiefangyingzi pluton from Chifeng area, southern Inner Mongolia, in China are studied to reveal their petrogenetic relationship with the host pluton. Furthermore, the coeval magmatic assemblage and its petrogenesis on the northern margin of the North China craton(NCC) are studied synthetically to elucidate their tectonic setting and the implications for the destruction of the NCC. Zircon U-Pb dating reveals that the mafic enclaves formed at 230.4 ± 2.2 Ma, which is similar to the age of the host pluton. The most basic mafic enclaves belong to weak alkaline rocks, and they display rare earth element(REE) and trace element normalized patterns and trace element compositions similar to those of ocean island basalt(OIB). In addition, they have positive εNd(t) values(+3.84 to +4.94) similar to those of the Cenozoic basalts on the northern margin of the NCC. All of these geochemical characteristics suggest that the basic mafic rocks originated from the asthenosphere. Petrological and geochemical studies suggest that the Jiefangyingzi pluton and the intermediate mafic enclaves were formed by the mixing of the asthenosphere-derived and crust-derived magmas in different degrees. The Mid-Late Triassic magmatic rocks on the northern margin of the NCC could be classified into three assemblages according to their geochemical compositions: alkaline series, weak alkaline–sub-alkaline series and sub-alkaline series rocks. Petrogenetic analyses suggest that the upwelling of the asthenosphere played an important role in the formation of these Mid-Late Triassic magmatic rocks. Basing on an analysis of regional geological data, we suggest that the northern margin of the NCC underwent destruction due to the upwelling of the asthenosphere during the Mid-Late Triassic, which was induced by the delamination of the root of the collisional orogeny between Sino-Korean and Siberian paleoplates in Late P

关键词： mafic enclave craton destruction asthenosphere Mid-Late Triassic North China craton

Permian-Triassic magmatic evolution of granitoids from the southeastern Central Asian Orogenic Belt:Implications for accretion leading to collision

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Science China earth Sciences 2021年第5期64卷 788-806页

作者： Didi WU Shan LI David CHEW Tieyi LIU Donghai GUO key laboratory of deep-earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Department of Geology School of Natural SciencesTrinity College DublinDublin 2Ireland

Many orogenic belts in the world exhibit accretionary and collisional orogenic phases to varying *** accretion evolves into collision of the Central Asian Orogenic Belt(CAOB),the largest Phanerozoic accretionary orogenic belt,is an intriguing *** this paper,we present new U-Pb age,geochemical and isotopic data for Permian-Triassic granitoids from middle Inner Mongolia,Northern China in the southeastern CAOB,and delineate the magmatic transition from subduction to(soft)*** magmatic record of soft collision is identified and characterized by thickened lower crust-derived high Sr/Y granitoids with a sub-linear distribution along the Solonker suture *** from Early Permian to Late Permian became more enriched in whole-rock Nd and zircon Hf isotopic compositions(εNd(t)values from 2.4 to-19.5,εHf(t)values from 11.6 to-33.7),indicating increasing incorporation of old *** change in peak timing of magmatism from west(ca.264 Ma)to east(ca.251 Ma)along the Solonker suture zone implies"scissor-like"closure of the Paleo-Asian *** with previous studies,a three-stage tectonic model from the Permian to Triassic by accretion leading to collision on the south-eastern margin of CAOB is proposed.(1)Early Permian(>ca.285 Ma):Juvenile magmatism on an active continental margin with double-sided subduction of the Paleo-Asian Ocean;(2)Middle Permian to Middle Triassic(ca.285–235 Ma):Magma source transition from juvenile to old crust induced by a tectonic switch from arc to"scissor-like"closure and subsequent intracontinental orogenic contraction;(3)Late Triassic(

关键词： Central Asian Orogenic Belt(CAOB) Accretionary orogeny Tectono-magmatic evolution Soft collision

A New Fossil Erinaceidae from the Shajingyi Area in the Lanzhou Basin, China

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Acta Geologica Sinica(English Edition) 2019年第4期93卷 789-798页

作者： LI Zhichao LI Yongxiang XUE Xiangxu LI Wenhou ZHANG Yunxiang YANG Fu School of earth Science and resources Chang’an UniversityXi’an 710054China State key laboratory of Continental dynamics Department of GeologyNorthwest UniversityXi’an 710069China key laboratory of Coal resources Exploration and Comprehensive Utilization Ministry of Land and ResourcesXi’an 710021China

Here,we describe a new primitive Erinaceidae species,Oligoechinus lanzhouensis ***.,based on a specimen from late Oligocene strata of the Lanzhou Basin,Gansu *** characteristics are as follows:the M1 width is longer than the length,the metastyle extends far disto-labially,the posterior margin has strong curve and a distinct metaconule that is connected to the protocone by a postprotocrista is located in the centre of the *** posterior arm of the metaconule is poorly *** the P4,the pterion of the metastyle is less developed and the metacone is *** addition,*** has a premolar larger than the canine tooth(P2>C)and P3 had no molarisation,characters also possessed by ***,*** was similar to Mioechinus based on architectural tooth features,demonstrating a closed genetic *** Erinaceidae are relatively rare before the *** discovery of *** provides an important insight into the origin of Mioechinus in China and the early evolution of the *** analysis shows that a relatively recent ancestor of Mioechinus had probably existed in the early Oligocene and that *** was likely an ancestral type of Mioechinus gobiensis,and its systematic position should be located at a transitional position between Amphechinus and Mioechinus.

关键词： Erinaceidae Oligoechinus Lanzhou basin Oligocene

Petrogenesis and Tectonic Implications of the Paiku Leucogranites,Northern Himalaya

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Journal of earth Science 2019年第3期30卷 525-534页

作者： Zhengbin Gou Xin Dong Baodi Wang Chengdu Center China Geological SurveyChengdu 610081 China key laboratory of deep-earth dynamics of ministry of Natural resources Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China

The Himalayan leucogranites provide insights into the partial melting behavior of relatively deeper crustal rocks and tectono-magmatic history of the Himalayan Orogen. The Paiku leucogranites of northern Himalaya can be subdivided into two-mica leucogranite(TML), garnet-bearing leucogranite(GL), cordierite-bearing leucogranite(CL), and tourmaline-bearing leucogranite(TL). All of them are high-K, peraluminous, calc-alkalic to alkali-calcic rocks. They are enriched in light rare earth elements(LREE) and large ion lithophile elements(LILE), and show pronounced negative anomalies of Sr, Ba, K and Ti, but positive anomalies of Nb and Rb. LA-ICP-MS U-Pb zircon dating of one TML, one GL, and two CL samples yielded variable 206Pb/238U ages ranging from 23.6 to 16.1 Ma, indicating the Paiku leucogranites underwent a low degree of partial melting process. Combining with previous studies, we suggest the Paiku leucogranites were derived from partial melting of metasedimentary rocks of the Higher Himalayan Sequence(HHS). The GL and TL mainly resulted from the muscovite-dehydration melting, whereas the TML and CL were mainly derived from the biotite-dehydration melting. Finally, it is concluded that the Paiku leucogranites were probably formed during the subduction of the Indian crust.

关键词： Paiku leucogranites petrochemistry U-Pb geochronology dehydration melting tectonic implications northern Himalaya

The Boninite-like Dolerites in the Xigaze Ophiolites, Tibet: Similar to the MORB-like Dolerites

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Acta Geologica Sinica(English Edition) 2020年第S1期94卷 73-75页

作者： YANG Shengbiao YANG Jingsui LI Yuan LI Ruibao Center for Advanced Research on the Mantle(CARMA) Key Laboratory of Deep-Earth Dynamics of Ministry of Land and ResourcesInstitute of GeologyChinese Academy of Geological SciencesBeijing 100037 School of earth Sciences and resources Chang’an UniversityXi’anShaanxi 710054

The Early Cretaceous Xigaze ophiolites(XO)exposed along the central segment of the more than 2000 km long Yarlung Zangbo Suture Zone in southern Tibet,preserved the structure of the upper mantle and oceanic crust,is interpreted as a definite record of Neo-Tethys oceanic *** evolution models of the XO have been proposed since the 1980s(Nicolas et al.,1981;Hébert et al.,2012;Maffione et al.,2015).However,the geodynamic environment of the XO whether at a MOR or SSZ remains *** key evidence for the identification of the SSZ ophiolite,the boninite-like dolerites from the XO are still controversial and poorly constraint(Chen et al.,2003;Bao et al.,2013;Dai et al.,2013).According to previous reports,dolerites were subdivided to MORB-like type and boninite-like type(Chen et al.,2003;Dai et al.,2013).Apart from high-SiO2(>52 wt%),high MgO(>8 wt%)and low-TiO2(<0.5 wt%),we found the boninite-like and MORB-like dolerites are indistinguishable in outcrop,mineral and *** are sills invaded into mantle sequence of the XO,with 50.35–56.80 wt%SiO2,0.32–1.19 wt%TiO2,7.39–8.89 wt%Fe2O3T,5.50–10.42 wt%MgO and Mg#of 0.49–***-like dolerites display trace element and REE patterns similar to those of most fore-arc or/and back-arc basalts from Izu-Bonin-Mariana(IBM),*** in large ion lithophile elements(LILEs,***,Rb,Ba,Pb,U)and depletion in high-field strength elements(HFSE,Nb,Ta)(Fig.1).Boninite-like dolerites resemble the MORB-like dolerites in trace elements and REE patterns,excepting for lower concentrations in REE,but distinct from the boninites discovered from the IBM or Troodos ophiolite(Fig.1c,d).Th in both dolerites deviate from the MORB array with negative slopes on the Th/Yb ***/Yb diagram(Fig.2a),suggesting constant subduction component added to the mantle source(Pearce et al.,1995).We chose depleted MORB source Mantle(DMM,Workman and Hart,2005)as the starting composition computing immobile element contents for primary melt

关键词： Yarlung Zangbo suture zone Xigaze ophiolite depleted mantle mid-ocean ridge

Metamorphic P-T-t Path of UHT Granulites from the North Tongbai Orogen, Central China

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Journal of earth Science 2018年第5期29卷 1116-1131页

作者： Hua Xiang Zeming Zhang Liming Zhao Zengqiu Zhong Hanwen Zhou key laboratory of deep-earth dynamics Institute of Geology Chinese Academy of Geological Sciences School of earth Sciences and resources China University of Geosciences School of earth Sciences China University of Geosciences

Although zircon U-Pb geochronometer has been widely used for dating metamorphism in moderate- to high-grade metamorphic rocks, it is still difficult to link the zircon U-Pb age to pressure and temperature （P-T） conditions. In this study, zircon trace elements and Hf isotopes and REE partitioning between zircon and garnet are adopted to track the formation condition of zircon in the granu- lites from North Tongbai Orogen, Central China. Combined with previous metamorphic P-T path results, a quantitative integrated anticlockwise P-T-t path was established for Tongbai granulites. These grauulites recorded an early low-P heating followed by a dramatic pressure increase. Evidence for the prograde history （M1） is provided by cordierite, orthopyroxene and biotite inclusions in garnet. The prograde metamorphism occurred at around 443±3 Ma, with P-T conditions of ca. 730-820 ℃ and 〈6 kbar. The peak metamorphic （M2） condition is 〉920 ℃ and 8.5-10 kbar and the peak metamorphism age is ca. 432±4 Ma. At around 419 Ma, the granulites suffered an amphibolite-facies retrograde metamorphism （M3）, represented by the replacement of garnet by biotite and plagioclase, and clinopyroxene by amphibole, with metamorphic condition of ca. 700℃ and ca. 7 kbar. The last retrograde metamorphism （M4） is a greenschist-facies overprint with an age of ca. 404 Ma. It is concluded that the meta- morphism of Tongbai granulite lasted for more than 40 Ma, including a stage of more than 20 Ma granulitc-facies metamorphism. The prolonged granulite-facies metamorphism resulted from the continuous northward subduction of the Shangdan oceanic crust beneath the North Qinling terrane.

关键词： granulites zircon U-Pb dating P-T-t path trace element Ln-Hf isotope Tongbai Orogen.