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Geochronology and geochemistry of the W-Mo-ore-related granitic rocks from eastern Ningzhen,lower Yangtze river belt,eastern China

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Acta Geochimica 2022年第2期41卷 288-306页

作者： Fangyue Wang Yongjie Guo Haiyang Yan Haiou Gu He Sun Can Ge Present Address:School of Resources and Environmental Engineering Hefei University of TechnologyHefei 230009China Ore Deposit and Exploration Center Hefei University of TechnologyHefei 230009China Anhui Institute of Geological Survey(Anhui Institute of Geological Sciences) Hefei 230001China

Here we present zircon U–Pb–Hf and wholerock major and trace element studies of eastern Ningzhen W-Mo-ore-related magmatic rocks,Yushan and Longwangshan granitic rocks,to constrain their form timing,magma sources,and tectonic settings.The results showed that the two plutons were formed in the Early Cretaceous with;Pb/;U ages of 107.8±1.2 and 105.2±1.5 Ma(;Pb/;U),respectively.The trapped/residual zircons are mainly distributed in 2.0–2.5 Ga.The two intrusions are characterized by high silicon(68.60–73.99%),high aluminum(13.56–15.02%),high Mg#(47–55),high Sr,Sr/Y,LaN/YN,and low Yb,falling into high Mg#adakitic rock region.The zirconεHf(t)values of the two intrusions range from-24.8 to-13.2,indicating an ancient continental crust in their magma sources.The average Ti-inzircon temperature is 689°C,slightly higher than those of other high-Mg adakitic rocks in the lower Yangtze River belt,but lower than those of high-Mg adakitic rocks in the Southern Tanlu Fault(STLF).Zircon Ce;/Ce;show low oxygen fugacity(LWS-1:3–400,average 92;sample ZYS-4:9–382,average 93).These geochemical features indicate a thickened lower continental crust in the Eastern Ningzhen region in a subduction setting.Comparing the geochemical characteristics of the eastern Ningzhen to the western Ningzhen and other areas in the Lower Yangtze River Metallogenic Belt(LYRMB)and the high-Mg ore-barren adakitic rocks of the STLF,we propose that the magmatic rocks from eastern Ningzhen may be mainly from a thickened lower continental crust that hybridized with a very small part of mantle sources,while the west Ningzhen magmatic rocks may have experienced a higher degree of mantle contaminations in their source.The metallogenic differences between the eastern(W–Mo)and western(Cu–Fe–Pb–Zn)parts of Ningzhen also indicate different proportions of crustal materials in their magma source.

关键词： Ancient lower continental crust paleo-pacific plate High Mg#adaktic rocks Early cretaceous Ningzhen Crustal thickening

Nature and secular evolution of the lithospheric mantle beneath the North China Craton

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Science China Earth Sciences 2021年第9期64卷 1492-1503页

作者： Yanjie TANG Jifeng YING Yuepeng ZHAO Xinrang XU State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China

The Archean mantle lithosphere beneath the North China Craton(NCC)was transformed in the Mesozoic,leading to the craton destruction.Despite the significant breakthroughs in the craton studies,lithospheric transformation mechanisms are yet to be fully understood.Compositional variations of mantle-derived rocks and xenoliths provide insights into the nature of the mantle lithosphere before and after the craton destruction.The paleozoic lithosphere of the NCC is~200 km thick.It has a refractory mantle with an evolved isotopic signature.The Mesozoic mantle lithosphere was relatively fertile and highly heterogeneous.In the Cenozoic,the lithosphere in the eastern NCC is about 60–80 km thick.It has an oceanic-type mantle that is fertile in composition and depleted in the Sr-Nd isotopic signature.The Central Zone lithosphere is>100 km thick and has a double-layer mantle with an old upper layer and a new lower layer.The Western Block has a lithosphere of~200 km thick.The lithospheric mantle beneath the southern and northern margins and eastern part of the NCC has been transformed significantly by peridotite-melt reactions due to the multiple subductions of adjacent plates since the paleozoic.paleo-pacific subduction and the associated dynamic processes significantly alter the lithosphere based on the distribution of craton destruction.The involved mechanisms include mechanical intrusion of subduction plates,melt/fluid erosion,and local delamination.The lithospheric thinning of~120 km is relevant to the continental extension caused by subduction plate rollback and trench retreat.

关键词： Mantle xenoliths Lithospheric mantle transformation Circum-craton subductions Peridotite-melt reaction North China Craton paleo-pacific plate

Comparative geochemical study of the cherty rocks of the Taukha terrane(Sikhote-Alin)and its paleogeodynamic significance

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Acta Geochimica 2020年第4期39卷 539-560页

作者： Igor V.Kemkin Raisa A.Kemkina Far East Geological Institute Far Eastern Branch of Russian Academy of SciencesProspect 100-Letiya Vladivostoka159VladivostokRussia 690022 Far Eastern Federal University Soukhanova Street8VladivostokRussia 690950

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.

关键词： Geochemistry Radiolarian cherts Deposition environment paleo-pacific plate Sikhote-Alin

Recycling of crustal materials and implications for lithospheric thinning: Evidence from Mesozoic volcanic rocks in the Hailar-Tamtsag Basin, NE China

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Geoscience Frontiers 2021年第5期12卷 149-165页

作者： Zheng Ji Yan-Long Zhang Chuan-Biao Wan Wen-Chun Ge Hao Yang Yu Dong Yan Jing College of Earth Sciences Jilin UniversityChangchun 130061China Exploration and Development Research Institute Daqing Oilfield Limited CompanyDaqing 163712China

Late Mesozoic Nb-rich basaltic andesites and high-Mg adakitic volcanic rocks from the Hailar-Tamtsag Basin,northeast China,provide important insights into the recycling processes of crustal materials and their role in late Mesozoic lithospheric thinning.The Late Jurassic Nb-rich basaltic andesites(154±4 Ma)are enriched in large-ion lithophile and light rare earth elements,slightly depleted in high-field-strength elements,and have high TiO_(2),P_(2)O_(5),and Nb contents,and(Nb/Th)PM and Nb/U ratios,which together with the relatively depleted Sr-Nd-Hf isotopic compositions indicate a derivation from a mantle wedge metasomatized by hydrous melts from subducted oceanic crust.The Early Cretaceous high-Mg adakitic volcanic rocks(129-117 Ma)are characterized by low Y and heavy rare earth element contents,and high Sr contents and Sr/Y ratios,similar to those of rocks derived from partial melting of an eclogitic source.They also have high Rb/Sr,K_(2)O/Na_(2)O,and Mg#values,and high MgO,Cr,and Ni contents.These geochemical features suggest that the adakitic lavas were derived from partial melting of delaminated lower continental crust,followed by interaction of the resulting melts with mantle material during their ascent.Our data,along with available geological,paleomagnetic,and geophysical evidence,lead us to propose that recycling of paleo-pacific oceanic crustal materials into the upper mantle due to flat-slab subduction and rollback of the paleo-pacific plate during the late Mesozoic likely provided the precondition for lithospheric thinning in northeast China,with consequent lithospheric delamination causing recycling of continental crustal materials and further lithospheric thinning.

关键词： Late Mesozoic Lithospheric thinning Hailar-Tamtsag Basin paleo-pacific plate Volcanic rock

Source and possible tectonic driver for Jurassic-Cretaceous gold deposits in the West Qinling Orogen, China

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Geoscience Frontiers 2019年第1期10卷 107-117页

作者： Yafei Wu Jianwei Li Katy Evans Denis Fougerouse Kirsten Rempel State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan School of Earth and Planetary Sciences The Institute for Geoscience Research (TIGeR) Curtin University School of Earth Resources China University of GeosciencesWuhan State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences

The West Qinling Orogen(WQO) in Central China Orogenic Belt contains numerous metasedimentary rock-hosted gold deposits(>2000 t Au), which mainly formed during two pulses: one previously recognized in the Late Triassic to Early Jurassic(T3 - J1) and one only recently identified in the Late Jurassic to Early Cretaceous(J3 - K1). Few studies have focused on the origin and geotectonic setting of the J3 - K1 gold deposits.Textural relationships, LA-ICP-MS trace element and sulfur isotope compositions of pyrites in hydrothermally altered T3 dykes within the J3 - K1 Daqiao deposit were used to constrain relative timing relationships between mineralization and pyrite growth in the dykes, and to characterize the source of ore fluid. These results are integrated with an overview of the regional geodynamic setting, to advance understanding of the tectonic driver for J3 - K1 hydrothermal gold systems. Pyrite in breccia-and dykehosted gold ores at Daqiao have similar chemical and isotopic compositions and are considered to be representative of J3 - K1 gold deposits in WQO. Co/Ni and sulfur isotope ratios suggest that ore fluids were derived from underlying paleozoic Ni-and Se-rich carbonaceous sedimentary rocks. The geochemical data do not support the involvement of magmatic fluids. However, in the EQO(East Qinling Orogen), J3 - K1 deposits are genetically related to magmatism. Gold mineralization in WQO is contemporaneous with magmatic deposits in the EQO and both are mainly controlled by NE-and EWtrending structures produced by changes in plate motion of the paleo-pacific plate as it was subducted beneath the Eurasian continent. We therefore infer that the J3 - K1 structural regime facilitated the ascent of magma in the EQO and metamorphic fluids in the WQO with consequent differences in the character of contemporaneous ore deposits. If this is correct, then the far-field effects of subduction along the eastern margin of NE Asia extended 1000's of km into the continental interior.

关键词： Pyrite LA-ICP-MS Sulfur isotopes Daqiao gold deposit West Qinling Orogen paleo-pacific plate Jurassice Cretaceous

Structure of the Upper Mantle and Transition Zone Beneath the South China Block Imaged by Finite Frequency Tomography

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Acta Geologica Sinica(English Edition) 2016年第5期90卷 1637-1652页

作者： SUN Ya LIU Jianxin TANG Youcai CHEN Jiawei ZHOU Keping CHEN Bo School ofGeosciences andlnfo-Physics Central South University Changsha 410083 China. School of Resources and Safety Engineering Central South University Changsha 410083 China Key Laboratory ofmetallogenicprediction of Non-Ferrous metals Ministry of Education Central South University Changsha 410083 China. State Key Laboratory of Petroleum Resource and Prospecting and Unconventional Natural Gas Institute China University of Petroleum Beij'ing 102249 China. Key Laboratory of CrustalDynamics Institute of Crustal Dynamics CEA Beijing 100085 China

We applied the finite frequency tomography method to S wave data recorded by 350 broadband stations beneath the South China Block（SCB） and its surroundings from earthquakes occurring between July 2007 and July 2010,to better understand upper mantle deformation.Differential travel-times in the pair of stations with appropriate weighting for each station are used in the inversion.Our results are consistent with previous tomography that show a high velocity anomaly beneath the Sichuan basin and a high velocity anomaly in the transition zone beneath the Yangtze Craton.However,the resolution of mantle heterogeneity provides new insight into the tectonic framework of subduction of Burmese lithosphere in the west part of the study region and subduction of oceanic lithosphere in the east.In the subduction realm,west of 107°E,a significant fast S-wave anomaly is located on the southeast of Sichuan Basin.East of 107°E,and two narrow and discontinuous fast S-wave anomalies occur at a depth of 400-600 km beneath the middle of the South China block overlain by the pronounced low S-wave anomalies at a depth of 100 and 400 km.If the fast anomalies located in the mantle transition zone represent stagnant slabs,their fragmented nature may suggest that they could be produced by different episodes of subduction beneath western pacific island and the above slow velocity anomaly may associated with the back-arc regions of ongoing subduction.In addition,tomography also reveals an anomalously high S-wave velocity continental root extends eastward to a depth 400 km beneath the eastern Sichuan Basin.This anomaly may be related to eastern extrusion of Indian lithosphere associated with the collision of India and Eurasia.Moreover,our results also show large slow anomalies beneath the Red River fault region connected to deeper anomalies beneath the South China Fold Belt and South China Sea.AH these observations are consistent with the scenario that the South China block has been built by both of subduction of paleopacific plate and eastward

关键词： finite frequency tomography South China Block station pairs subduction paleo-pacific plate

U-Pb-Hf isotopes and petrogenesis of Late Jurassic akakitic quartz monzodiorite in Xingcheng area,western Liaoning Province

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Global Geology 2021年第3期24卷 129-143页

作者： YAN Xiangyu YANG Debin MU Maosong HAO Leran College of Earth Sciences Jilin UniversityChangchun 130061China

The petrogenesis and geodynamic setting of the Late Jurassic Baita porphyry quartz monzodiorite in Xingcheng-Liaoxi area provide information for understanding the Mesozoic tectonic evolution of the northeastern North China Craton.In this paper,geochronological,whole-rock geochemical,and in-situ zircon Hf isotopic analyses of Baita porphyry quartz monzodiorite were investigated to constrain the crystallization age and petrogenesis.Zircons exhibit typical oscillatory zoning in cathodoluminescence images and show relatively high Th/U ratios(0.78-1.62),and U-Pb analyses indicate that these rocks were crystallized during the Late Jurassic(159±1 Ma).Geochemically,they are characterized by high contents of SiO 2(65.21wt%-65.31wt%),Al 2O 3(16.29wt%-16.31wt%),Sr(521×10^(-6)-539×10^(-6)),and Sr/Y ratio(45.1-47.8)but low Y(10.9×10^(-6)-12.0×10^(-6)),with obvious adakitic geochemical affinities.These above-mentioned findings,combined with their negativeε_(Hf)(t)values(-21.7 to-20.2),corresponding two-stage model age(T_( DM2))of 2579-2484 Ma,as well as low MgO(1.38wt%-1.39wt%),Cr(18.5×10^(-6)-19.5×10^(-6))and Ni(9.45×10^(-6)-9.46×10^(-6))values,indicate that Baita porphyry quartz monzodiorite may be generated by partial melting of the Neoarchean-paleoproterozoic thickened basaltic lower crust.Based on the results from this study and pre-vious regional studies,it is concluded that Baita porphyry quartz monzodiorite was spatially related to the westward subduction of the paleo-pacific plate.

关键词： Liaoxi Late Jurassic adakitic rocks thickened lower crust paleo-pacific plate

东北中生代增生杂岩及对古太平洋向欧亚大陆俯冲历史的制约（英文）

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东北中生代增生杂岩及对古太平洋向欧亚大陆俯冲历史的制约（英文...