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Acta Geochimica 2007年第3期26卷 305-311页

作者： LAI Shaocong, QIN Jiangfeng, LI Yongfeng, and LIU xin state key laboratory of continental dynamics, department of geology, northwest university, xi’an 710069, china state key laboratory of continental dynamics Department of GeologyNorthwestUniversityXi'an 710069China

Neogene volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, are represented by a typical intermediate-basic and intermediate alkaline rock association, with latite-trachyte as the main rock type. The results of chemical analysis are: SiO2=52%–62%, Al2O3>15%, Na2O/K2O>1 and MgO<3.30%. In addition, the volcanic rocks are LREE-enriched with LREE/HREE=10–13, (La/Yb)N=15–19, and show a weak negative Eu anomaly with δEu=0.71–0.89. The close relationship between Mg# and SiO2 and the co-variation of the magmatophile elements and ultra-magmatophile elements such as La/Sm-La and Cr-Tb indicate that this association of volcanic rocks is the product of comagmatic fractional crystallization. The rock association type and lower Sm/Yb values (Sm/Yb=3.23–3.97) imply that this association of volcanic rocks should have originated from partial melting of spinel lherzolite in the lithospheric mantle. On the other hand, the weak negative Eu anomaly and relative depletion in Nb, Ta and Ti reflect the features of terrigenous magma. So the Neogene Belog Co alkaline volcanic rocks should be the result of partial melting of the special crust-mantle transition zone on the Qinghai-Tibet Plateau.

关键词： major and trace elements Cenozoic volcanic rock mantle-crust transition zone Qinghai-Tibet Plateau

Multistage evolution of continental collision orogen:A case study for western Dabie orogen

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Chinese Science Bulletin 2009年第15期54卷 2568-2579页

作者： WU YuanBao state key laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, china university of Geosciences, Wuhan 430074, china state key laboratory of continental dynamics, department of geology, northwest university, xi’an 710069, china state key laboratory of Geological Processes and Mineral Resources Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China state key laboratory of continental dynamics Department of Geology Northwest University Xi’an 710069 China

The foramtion and evolution of collisional orogen is a prominent feature along convergent plate margins, and is generally a complex process. This article presents an integrated study of zircon genesis, U-Pb age and Lu-Hf isotope composition as well as geological characteristics for the western Dabie orogen to constrain its multi-stage evolution history. The results suggest that the formation of oceanic crust in the Huwan area was constrained at ca. 400―430 Ma, which was slightly later than the collision of the northern Qinling with the North china Block. It formed in a marginal basin in the northern margin of the Yangtze Block. The peak metamorphism of eclogite in the Huwan area occurred at ca. 310 Ma, and the timing of the initial exhumation of oceanic eclogite was about 270 Ma. The high to ultrahigh pressure (HP-UHP) metamorphic rocks in the xinxian and the Hong'an metamorphic zones have the same ages and natures as those of the HP-UHP metamorphic rocks in the other Dabie-Sulu terrains, and also have experienced multi-stage exhumation, and thus can be taken as a coherent part of the Dabie-Sulu orogen. Therefore, the Qinling-Dabie-Sulu orogen is a typical multi-stage continental collision orogen, with an amalgamation process extending more than 200 Ma.

关键词：大别造山带大陆碰撞西部演变超高压变质岩碰撞造山带苏鲁造山带变质岩区

Geochronological evidence of Indosinian(high-pressure) metamorphic event and its tectonic significance in Taxkorgan area of the Western Kunlun Mountains,NW china

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Science china Earth Sciences 2010年第10期53卷 1445-1459页

作者： YANG WenQiang1,LIU Liang1,CAO YuTing1,WANG Chao1,2,HE ShiPing2,LI RongShe2 & ZHU xiaoHui1 1 state key laboratory of continental dynamics,department of geology,northwest university,xi’an 710069,china 2 xi’an Institute of geology and Mineral Resource,xi’an 710054,china 1. state key laboratory of continental dynamics Department of Geology Northwest University Xi’an 710069 China2. Xi’an Institute of Geology and Mineral Resource Xi’an 710054 China

The CL images,LA-ICP-MS in situ trace elements analysis,and U-Pb dating for zircons indicate that the metamorphic ages of the sillimanite-garnet-biotite gneiss and the garnet-amphibole gneiss from eastern Taxkorgan of the Western Kunlun Mountains are 220±2 and 220±3 Ma respectively,and their protolith ages are younger than 253±2 and 480±8 Ma *** samples were collected at the same outcrops with HP mafic granulite and HP pelitic *** assemblage of the sillimanite-garnet-biotite gneiss(Grt+Sill+Per+Q) is consistent with that of HP pelitic granulite at early high amphibolite-granulite facies *** assemblage of the garnet-amphibole gneiss(Grt+Amp+Pl+Q) is consistent with retro-metamorphic assemblage of HP mafic granulite at amphibolite facies *** dating results suggest that these HP granulites underwent peak metamorphism at 220±2 to 253±2 ***,the Kangxiwar tectonic zone was probably formed by subduction and collision of the Paleo-Tethys Ocean during *** ages of the two samples,together with previously published U-Pb zircon dating age,suggest that the sillimanite-garnet schist-quartzite unit is a late Paleozoic unit,not a part of the Paleoproterozoic Bulunkuole Group.

关键词： Western Kunlun Mountains LA-ICP-MS zircon dating Bulunkuole Group Indosinian Kangxiwar tectonic zone

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

Geochemistry of high-Mg andesites from the early Cretaceous Yixian Formation, western Liaoning: Implications for lower crustal delamination and Sr/Y variations

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Science china Earth Sciences 2006年第9期49卷 904-914页

作者： WANG xiaorui1, GAO Shan1,2, LIU xiaoming1, YUAN Honglin1, HU Zhaochu1, ZHANG Hong1,3 & WANG Xuance4 1. state key laboratory of continental dynamics, department of geology, northwest university, xi`an 710069, china 2. state key laboratory of Geological Processes and Mineral Resources, china university of Geosciences, Wuhan 430074, china 3. Shenyang Institute of geology and Mineral Resources, Shenyang 110032, china 4. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, china 1. state key laboratory of continental dynamics Department of Geology Northwest University Xi’an 710069 China 2. state key laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China 3. Shenyang Institute of geology and Mineral Resources Shenyang 110032 China 4. Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

85 volcanic rocks of the Yixian Formation from the Sihetun type section werecollected and analyzed for geochemical and isotopic compositions. Major element compositionsindicate that the Sihetun volcanic rocks are high magnesium andesites with some basalts occurring atthe bottom of section. The Sihetun high magnesium andesites (SiO_2 = 52.82-59.31 wt%, Al_2O_3=14.15-16.35wt%) show many characteristics of adakites such as depletion in heavy rare-earth elements(HREE; Yb = 1.03-1.88 μg/g) and Y(12-20 μg/g) and high Sr (620-1323 μg/g) and Sr/Y(32-88), withhigh La_N/Yb_N ratio (10-25). They share similar major and trace element characteristics to volcanicrocks from the xinglonggou Formation except their lower Nd isotope ratios (^(143)Nd/^(144)Nd(130Ma) = 0.5118-0.5119, ε_(Nd) (130Ma) = -11.6-13.8, ^(87)Sr/^(86)Sr (130 Ma) = *** were interpreted in a way that eclogite that formed at the base of thickened Archean lowercrust of the North china craton foundered into the convecting mantle and subsequently melted andinteracted with peridotite. However, compared to the xinglonggou volcanic rocks, the source of theSihetun magma contained more ancient continental crustal material in order to explain its evolved Ndisotopes. The age of the Sihetun Formation was 120 to 130 Ma, and this indicates that delaminationlasted to the early Cretaceous period. The Sr contents and Sr/Y ratios of the Sihetun high-Mgandesites show significant negative correlations with SiO_2 for samples with SiO_2 > 56%. Thesesuggest that the Sr and Sr/Y values were reduced due to fractional crystallization of ***, the effect of crystallization on volcanic Sr and Sr/Y ratio has to be taken intoaccount.

关键词： High-Mg andesite, Adakite, Yixian Formation, North china Craton, delamination.

Sr-Nd-Pb isotopes of the Early Paleozoic maficultramafic dykes and basalts from South Qinling belt and their implications for mantle composition

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Science china Earth Sciences 2007年第9期50卷 1293-1301页

作者： ZHANG ChengLi1,2, GAO Shan1, 2, YUAN HongLin1, ZHANG GuoWei1, YAN Yunxiang1, LUO JingLan1 & LUO JinHai1 1 state key laboratory of continental dynamics, department of geology, northwest university, xi’an 710069, china 2 state key laboratory of Geological Progresses and Mineral Resources, china university of Geosciences, Wuhan 430074, china state key laboratory of continental dynamics Department of Geology Northwest University Xi'an 710069 China state key laboratory of Geological Progresses and Mineral Resources China University of Geosciences Wuhan 430074 China state key laboratory of continental dynamics Department of Geology Northwest University Xi'an 710069 China

Late Early Paleozoic mafic-ultramafic dykes and volcanic rocks from the South Qinling belt are char- acterized by εNd( t ) = +3.28― +5.02, (87Sr/86Sr)i= 0.70341― 0.70555, (206Pb/204Pb)i = 17.256― 18.993, (207Pb/204Pb)i= 15.505―15.642, (208Pb/204Pb)i=37.125―38.968, ?8/4=21.18―774.43, ?7/4=8.11―18.82. These charac- teristics suggest that they derived from a Middle Neoproterozoic mantle with isotopic compositions of mixed HIMU, EMII and minor EMI components. We interpret that these rocks were melting products of depleted mantle modified by subducted ancient oceanic crust and continental margin sediments along the northern margin of Yangtze block during Early Neoproterozoic.

关键词： mafic dykes Sr-Nd-Pb isotope mantle source South Qinling belt

Re-Os isotopic constraint to the age of in komatiites in the Neoarchean Guyang greenstone belt,North china Craton

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Re-Os isotopic constraint to the age of in komatiites in the...

Silurian granulite-facies metamorphism,and coeval magmatism and crustal growth in the Tongbai orogen,central china

中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： MA XuDong~(1*),GUO JingHui~1,CHEN Liang~2 & CHU ZhuYin~1 1 state key laboratory of Litho spheric Evolution,Institute of geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,china 2 state key laboratory of continental dynamics,department of geology,northwest university,xi’an 710069,china

The 2.5 Ga Guyang greenstone belt is a major lithological unit in the northwestern part of the North china *** have recently been identified to occur within the lower part of the meta-volcanic sedimentary sequence of the greenstone *** biggest komatiite near Guyang has been mapped out,which is 500 m long and 50 m wide lenticular ***-Os isotopic compositions of 9 samples were analyzed to date the *** Os contents are from 0.88 to 2.63 ppb,identical with typical komatiites, and slightly lower than the normal *** Os/Os ratios are from 0.1115 to 0.1197,which are lower enough to exclude the origin of Phanerozoic magma as widely developed in adjacent *** calculated Re depletion model ages(T) are from 1346 to 2454 Ma,among them the oldest age of 2454 Ma gives the minimum evaluation for the formation age of the Guyang ***,the komatiites are a part of the Guyang greenstone belt,indicating high degree melting of mantle during～2.5 Ga crustal growth event.

关键词： komatiite Re-Os isotope Guyang greenstone belt Archean North china Craton

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Silurian granulite-facies metamorphism,and coeval magmatism ...

Thoughts on studies of china continental geology and tectonics

中国矿物岩石地球化学学会第13届学术年会

作者： WANG Hao~1,WU Yuan-bao~(1,2),GAO Shan~1,ZHANG Hong-fei~1, LIU xiao-chi~1,GONG Hu-jun~2,PENG Min~3,WANG Jing~4,YUAN Hong-lin~2 1.state key laboratory of Geological Processes and Mineral Resources,Faculty of Earth Sciences,china university of Geosciences, Wuhan 430074,china 2.state key laboratory of continental dynamics,department of geology,northwest university,xi’an 710069,china 3.Institute of Geophysical and Geochemical Exploration CAGS,Langfang 065000,china 4.Anhui Institute of geology,Hefei 230001,china

It is intriguing whether the formation of granulite in an orogenic belt is related to magmatism and crustal *** Tongbai orogen is one of the particular areas in the Qinling-Tongbai-Dabie-Sulu orogen that contains both granulites and associated arc magmatic rocks,and thus is an optimal place to address this ***,the formation age and genesis of the granulites and their relations to the magmatic rocks have not yet been well *** situ LA(MC)-ICPMS U-Pb dating,and trace element and Lu-Hf isotope analyses were undertaken on zircon grains from gneiss,granulite,gabbro and granodiorite *** zircons in three granulite samples and a gneiss sample have core-rim *** cores have oval or rounded shapes,oscillatory zones,high Th/U ratios and variable U-Pb ages,suggesting a detrital *** youngest group of the detrital zircons yields a weighted mean pb/U age of(450-±5) Ma,which is interpreted as the maximum depositional age of their protoliths.A major age cluster is ca.450～490 Ma,corresponding to prolonged arc magmatism in the northern Tongbai and Qinling *** group of ages range from 660 to 950 Ma,implying that the Qinling Group

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Progress in Natural Science:Materials International 2006年第10期16卷 1022-1026页

作者： ZHANG Guowei, GUO Anlin and YAO Anping (Ministry of Education key laboratory of continental dynamics, department of geology, northwest university, xi’an 710069, china) [a]Ministy if Education key laboratory of dynamics Department of Geology Northwest University Xi an China

As an important part of the global continents, china continent has long been situated in the peculiar tectonic position and experienced extremely complicated activities, which resulted in the regional unique characteristics for china continent on the global common geological background. These characteristics contain abundant information regarding scientific key issues of modern geological frontier. Thus, china continent can be a natural laboratory and excellent arena for the modern geosciences. The modern earth sciences have started entering the era featured with earth systematic science and beyond plate tectonics. How to take the regional advantage and exploit the treasure resource to participate the new theoretical and methodological creation is a historic opportunity and great challenge we are facing. This paper generalizes research priorities in four fields on china continental geology and tectonics for discussion. They are: china continental tectonics and dynamics; Mesozoic-Cenozoic crustal deformation and deep-seated processes in china continent and the adjacent regions; deep-seated dynamic background and evolutionary trend of crustal tectonic activities on the time scale of human existence; deep-seated background and processes of conjunction and transformation of different tectonic systems.

关键词： china continental geology and continental tectonics plate tectonics continental dynamics key scientific issues.

Identification of 3.5 Ga detrital zircons from Yangtze craton in south china and the implication for Archean crust evolution

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Progress in Natural Science:Materials International 2006年第6期16卷 663-666页

作者： LIU xiaoming, GAO Shan, LING Wenli, YUAN Honglin and HU Zhaochu (National key laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, china university of Geosciences, Wuhan 430074, china key laboratory of continental dynamics, department of geology, northwest university, xi' an 710069, china) [a]National key laboratory of Geological Processes and Mineral Resources Faculty of Earth Sciences China University of Geosciences Wuhan China [b]key laboratory of continental dynamics Department of Geology Northwest University China

The LA-ICP-MS U-Pb dating of hundreds of detrital zircon grains from the Sinian sandstones of Liantuo formation and tillites of Nantuo formation at Sanxia area in Yichang identified 3319-3508 Ma zircon grains. Their 207Pb/206Pb and 206Pb/238U ages show excellent agreement (concordia degree 99%-100% ). Their CL images exhibit well-developed oscillatory zoning and the Th/U ratios are within 0.46-0.76, implying that they are igneous zircons which formed during middle-early Archean. These zircons are the oldest ones discovered in Yangtze craton until now. However, the detrital zircons with ages older than 3. 3 Ga in the metamorphic rocks of Kongling group were not found by further investigation, which suggests the presence of crust older than high-grade metamorphic Kongling terrain in Yangtze craton.

关键词： early Archean detrital zircon zircon dating Yangtze craton.