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SHRIMP zircon U-Pb geochronology of early Mesozoic felsic igneous rocks from the southern Lancangjiang and its tectonic implications

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Science china Earth sciences 2006年第10期49卷 1032-1042页

作者： PENG Touping1,2. WANG Yuejun1, FAN Weiming1, LIU Dunyi3, SHI Yuruo3 & MIAO Laicheng4.1. key laboratory of Isotope Geochronology and Geochemistry, Guangzhou {2. of Geochemistry,{4., Guangzhou 51064., china 2. Graduate University of{4., beijing 100039, china 3. SHRIMP isotope laboratory, chinese academy of Geological sciences, beijing 100037, china 4. {2. of geology and Geophysics,{4., beijing 10002., china key laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Graduate University of chinese academy of sciences Beijing China SHRIMP isotope laboratory Chinese Academy of Geological Sciences Beijing China institute of geology and Geophysics Chinese Academy of Sciences Beijing China

The SHRIMP zircon U-Pb geochronology of three typical samples, including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang, western Yunnan Province. The analyses of zircons for the biotite monzonitic granites from the northern (02.X-137) and southern (2.JH-10) Lincang batholith show the single and tight clusters on the concordia, and yield the weighted mean 2.6Pb/2.8U ages of 2.9.4.± 3.0 Ma and 2.0.4.± 3.6 Ma, respectively, representing the crystallized ages of these granites. The zircons for the rhyolitic sample (02.X-95) from the Manghuai Formation give a weighted mean 2.6Pb/2.8U age of 2.1.0 ± 5.0 Ma. These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age. In combination with other data, it is inferred that both were generated at a narrow age span (~2.0 Ma) and were originated from the postcollisional tectonic regime. An early Proterozoic 2.6Pb/2.8U apparent age of 1977±4. Ma is additionally obtained from one zircon from the biotite monzonitic granite (southern Lincang batholith), indicative of devel- opment of the early Proterozoic Yangtze basement in the region. These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys, western Yunnan Province.

关键词： SHRIMP zircon U-Pb dating, Middle Triassic, Lincang granitic batholith, Manghuai Formation rhyolite, southern Lancangjiang.

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^(4.)Ar/^(39)Ar dating of shear deformation of the Xianshuihe fault zone in west Sichuan and its tectonic significance

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Science china Earth sciences 2004年第9期47卷 794-803页

作者： ZHANG Yueqiao1, CHEN Wen2. 3 & YANG Nong1 1. institute of geomechanics, {2. {4. of Geological sciences, beijing 100081, china 2. institute of geology, {2. {4. of Geological sciences, beijing 100037, china 3. institute of geology and Geophysics, chinese academy of sciences, beijing 10002., china institute of geomechanics Chinese Academy of Geological Sciences Beijing China institute of geology Chinese Academy of Geological Sciences Beijing China institute of geology and Geophysics Chinese Academy of Sciences Beijing China

Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results document two thermal events during the sinistral shear. The early event (12.10 Ma) corresponds to rapid cooling of the Zheduoshan granitic massif from above 700℃ to below 350℃. The late event (5-3.5 Ma) corresponds to cooling of granites intruded along the eastern side of the fault zone. These dating results provide important thermochronological constraint on the timing of late Cenozoic eastward extrusion of the Chuan-Dian Block in the SE Tibetan margin.

关键词： Xianshuihe fault zone, Zheduoshan granitic massif, sinistral shear deformation, 4.Ar/39Ar dating, late Cenozoic.

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SILICA-SUPPORTED NICKEL AND ZIRCONIUM CATALYSTS FOR BRANCHED POLYETHYLENE

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chinese Journal of Polymer Science 2003年第4期21卷 453-458页

作者：孙文华 State key laboratory of {2. Plastics The Center for Molecular sciences {4. of Chemistry chinese academy of sciences beijing 100080 china Stt. key Lab. of Eng. Plastics Center for Molecular Sciences Chinese Academy of Sciences Beijing 100080 China

8-Aminoquinoline nickel dichloride and bis(cyclopentadienyl)zirconium dichloride (Cp_2.rCl_2. were supportedsimultaneously on silica to produce branched polyethylene successfully by combined polymerization. The supportedpolymerization results showed that the molecular weight of polyethylene increased while the molecular weight distributionbecame wider and the molecular chains of oligomers remaning in the final solution became shorter as compared to theoligomers obtained in polymerization processes with pure 8-aminoquinoline nickel dichloride catalysis, as well as theCp_2.rCl_2.and nickel combination system. With decreasing amount of Ni catalyst in the supported catalyst, the molecular chains of oligomers in the resulting solution became shorter, while α-olefin selectivity increased.

关键词： 8-Aminoquinoline nickel dichloride, Cp_2.rCl_2 Silica supported catalysts Branched polyethylene

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Patterns of platinum-group elements in mantle peridotite, granulite xenoliths and basalt in Hannuoba

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chinese Science Bulletin 1999年第18期44卷 1676-1681页

作者： CHU Xuelei, LI Xiaolin, XU Jiuhua and LIU Jianming1. The Research Center of Mineral Resources Exploration , chinese academy of sciences , beijing 100101,{2. 2. {4. of geology , chinese academy of sciences , beijing 10002.,{2. 3. {4. of High Energy Physics , chinese academy of sciences , beijing 100817 ,{2. 4. beijing University of Science and {14. , beijing 100083,{2. Corresponding author The Research Center of Mineral Resources Exploration Chinese Academy of Sciences Beijing China institute of geology Chinese Academy of Sciences Beijing China institute of High Energy Physics Chinese Academy of Sciences Beijing China beijing University of Science and engineering Beijing China

Neutron activation analysis after preconcentration of nickel sulfide fire assay was used in measurement of Ru, Ph, Pd, Os, Ir, Pt (i.e. PGE elements) and Au concentrations for basalt, mantle and granulite xenoliths in Hannuoba. The chondrite- and primitive mantle-normalized PGE patterns generally exhibit flat (for Iherzolite), negative slope (for harzburgite),

关键词： mantle xenolith granulite xenolith basalt platinum-group element Hannuoba.

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Characteristics and geological significance of olivine xenocrysts in Cenozoic volcanic rocks from western Qinling

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Progress in Natural Science:Materials International 2006年第12期16卷 1300-1306页

作者： SU Benxun~ 1,2.**, ZHANG Hongfu~1, XIAO Yan~ 1,2.and ZHAO Xinmiao~ 1,2.(1. State key {4. of Lithospheric Evolution, {2. of geology and Geophysics, chinese academy of sciences, beijing 10002., china 2. Graduate School of chinese academy of sciences, beijing 100039, china) State key laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Graduate School of chinese academy of sciences Beijing 100039 China

Cenozoic volcanic rocks from the Haoti, Dangchang County of the western Qinling Mountains, contain a few clearly-zoned olivines. These olivines are relatively big in grain sizes and usually have cracks or broken features. Their cores have similar compositions （Mg#=90.4.91.0） to those for the peridotitic xenoliths entrained in host volcanic rocks and their rims are close to the compositions of olivine phenocrysts （Mg#=85.5-81.9）. The CaO contents in these zoned olivines are lower than 0.1%. These features demonstrate that the clearly-zoned olivines are xenocrysts and disaggregated from mantle peridotites. The zoned texture was the result of the interaction between the olivine and host magma. Available data show that the volcanic rocks would have been derived from the mantle source metasomatized by subducted hydrathermally-altered oceanic crust. The formation of these Cenozoic volcanic rocks was perhaps related to the rapid uplift of the Tibetan Plateau.

关键词： Western Qinling Dangchang Haoti Cenozoic volcanic rocks olivine xenocrysts zoned texture.

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Isotopic feature and uranium dating of the volcanic rocks in the Okinawa Trough

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中国科学：地球科学英文版 2006年第4期49卷 375-383页

作者： HUANG Peng1,2. LI Anchun1, HU Ningjing2.3, FU Yongtao1& MA Zhibang4.1. institute of Oceanology, chinese academy of sciences, Qingdao 2.6071,{2. 2. Graduate School of the chinese academy of sciences, beijing 100039,{2. 3. institute of Soil Science, chinese academy of sciences, Nanjing 2.0008,{2. 4. institute of geology and Geophysics, chinese academy of sciences,{12.,{2. institute of Oceanology Chinese Academy of Sciences Qingdao China Graduate School of the chinese academy of sciences Beijing China institute of Soil Science Chinese Academy of Sciences Nanjing China institute of geology and Geophysics Chinese Academy of Sciences Beijing China

Volcanic rocks from the northern and middle Okinawa Trough were dated by ura- nium-series dating method. Differential fractions using magnetic procedure were designed to separate samples. New report on the ages and isotopic data of rocks in the northern trough (especially black pumice) was discussed. Based on the uranium dates and Sr-Nd isotopic ratio, magmatic evolution process of the Okinawa Trough was noted. Firstly, there have been wide silicic volcanic activities in the Okinawa Trough from late Pleistocene to present, and the volcanic rocks can be divided into three subgroups. Secondly, magma generally came from PREMA source area under the Okinawa Trough. Magmatic evolution in the northern trough was similar to the middle, but different to the south. Finally, volcanic activities indicated that opening of the southern Okinawa Trough did not happen due to the collision between Luson Arc and Eurasian Plate until the early Pleistocene.

关键词： Okinawa Trough, black pumice, uranium-series dating, Sr-Nd isotopic ratio, magmatic evolution.

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Principles and methods of quantitative analysis on b-axis disorder in 2.: 1 dioctahedral phyllosilicate

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chinese Science Bulletin 1997年第22期42卷 1908-1912页

作者： WANG Ling and ZHANG Zhenyu1. Changsha institute of Geotectonics, chinese academy of sciences, Changsha 4.0013,{2. 2. institute of geology, chinese academy of sciences, beijing 10002.,{2. Changsha institute of Geotectonics Chinese Academy of Sciences Changsha China institute of geology Chinese Academy of Sciences Beijing China

IN XRD patterns of clay minerals, a phenomenon that strong peaks often have (00l) and(hkl) (k=3n) indices and show symmetric figures can be seen commonly, while a minorityof reflection peaks (hkl) (k≠3n) are comparat... 详细信息

关键词： b-axis disorder pyrophvllile 2 phyllosilicate clay minerals dioctahedral minerals orientating structure of hy-droxyls crystal structure analysis DTA-TG.

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Kinematics and dynamics of the Mesozoic orogeny and late-orogenic extensional collapse in the Sino-Mongolian border areas

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Science china Earth sciences 2005年第7期48卷 849-862页

作者： ZHENG Yadong 1 & WANG Tao2.1. key laboratory of Orogenic Belts and Crustal Evolution (Peking University), Ministry of Education, {2. 100871,{4. 2. institute of geology, chinese academy of Geological sciences, {2. 100037,{4. key laboratory of Orogenic Belts and Crustal Evolution (Peking University) Ministry of Education Beijing 100871 China institute of geology Chinese Academy of Geological Sciences Beijinq 100037 China

The Sino-Mongolian border areas underwent two important tectonic events during Mesozoic time after late Paleozoic orogeny: a late Triassic to earlier Jurassic contractional event that resulted in a large-scale south-vergent thrust during the orogeny and a late Jurassic-earlier Cretaceous extensional event in a north-south direction that formed a metamorphic core complex. The kinematic and dynamic analyses show that the thrust sheet moved southwards with a kinematic vorticity number of ca. -0.10 and sub-horizontal maximum compressive stress axis that belongs to a contraction-thickening shear. The upper plate of the late-orogenic detachment relatively moved in a 165°direction. The average kinematic vorticity in its earlier stage was 0.74.that belongs to simple shear dominated shearing and related to the maximum compressive stress axes dipping at ～66°, while the later average kinematic vorticity was ～0.55°that belongs to pure shear dominated shearing with sub-vertical maximum compressive stress axes. This suggests that the thrusting led to the crust thickened and the lower plate rocks that were originally located in the upper crust depressed through a brittle-ductile transition zone into the lower crust and became warmer. The heated rocks trended to uplift since their increasing volume and decreasing density while the loading of the upper-plate rocks increased due to the structural thickening. Under the combined effect of the loading and the thermal-uplifting, the ductile shear zone in between increased in its component of vertical pure shear. Once its pure-shear component exceeded its simple-shear one the ductile shear zone became an extension-thinned shear zone. This progressive transitional process reflects internal and essential temporal and spatial relationships: the extensional factor nucleated during the crust thickening by thrusting and increase of the extensional factor finally led to late-orogenic collapse.

关键词： Mesozoic thrusting,late-orogenic collapse,kinematic vorticity number,stress state.

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Genesis of ^(2.0)Th excess in basalts from mid-ocean ridges and ocean islands:Constraints from the global U-series isotope database and major and rare earth element geochemistry

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Science china Earth sciences 2010年第10期53卷 1486-1494页

作者： ZHANG GuoLiang1,2.& ZENG ZhiGang1 1 key laboratory of Marine {2. and Environment,{4. of Oceanology,chinese academy of sciences,Qingdao 2.6071,china 2.Graduate University of chinese academy of sciences,beijing 10004.,china key laboratory of Marine {2. and Environment Institute of Oceanology Chinese Academy of Sciences Qingdao China Graduate University of chinese academy of sciences Beijing China

Based on 2.0Th-2.8U disequilibrium and major element data from mid-ocean ridge basalts(MORBs) and ocean island basalts(OIBs),this study calculates mantle melting parameters,and thereby investigates the origin of 2.0Th excess.(2.0Th/2.8U) in global MORBs shows a positive correlation with Fe8,Po,Na8,and Fmelt(Fe8 and Na8 are FeO and Na2. contents respectively after correction for crustal fractionation relative to MgO = 8 wt%,Po=pressure of initial melting and Fmelt=degree of melt),while 2.0Th excess in OIBs has no obvious correlation with either initial mantle melting depth or the average degree of mantle ***,compared with the MORBs,higher(2.0Th/2.8U) in OIBs actually corresponds to a lower melting *** suggests that the 2.0Th excess in MORBs is controlled by mantle melting conditions,while the 2.0Th excess in OIBs is more likely related to the deep garnet *** vast majority of calculated initial melting pressures of MORBs with excess 2.0Th are between 1.0 and 2.5 GPa,which is consistent with the conclusion from experiments in recent years that DU>DTh for Al-clinopyroxene at pressures of >1.0 *** initial melting pressure of OIBs is 2.2.3.5 GPa(around the spinel-garnet transition zone),with their low excess 2.6Ra compared to MORBs also suggesting a deeper mantle ***,excess 2.0Th in MORBs and OIBs may be formed respectively in the spinel and garnet stability *** addition,there is no obvious correlation of K2./TiO2.with(2.0Th/2.8U) and initial melting pressure(Po) of MORBs,so it is proposed that the melting depth producing excess 2.0Th does not tap the spinel-garnet transition *** and MORBs in both(2.0Th/2.8U) vs.K2./TiO2.and(2.0Th/2.8U) *** plots fall in two distinct areas,indicating that the mineral phases which dominate their excess 2.0Th are ***/Yb-Ce curves of fast and slow ridge MORBs are similar,while,in comparison,the Ce/Yb-Ce curve for OIBs shows more influence from *** mechanism

关键词： excess 2.0Th clinopyroxene garnet spinel-lherzolite mid-ocean ridge ocean island

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U-Pb dating of zircon from the bed parallel anatectic granitic intrusion in the Baoban group in Hainan Island and the tectonic implication

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Science china Earth sciences 2005年第12期48卷 2092-2103页

作者： DING Shijiang1, HU Jianmin2. SONG Biao3,4. CHEN Mulun1, XIE Shengzhou1 & FAN Yuan1 1. Geological Surveying institute of Hainan, Haikou 5702.6, china 2. institute of geomechanics, chinese academy of Geological sciences, beijing 100081, china 3. beijing Center of SHRIMP, beijing 100037, china 4. institute of geology, chinese academy of Geological sciences, beijing 100037, china Geological Surveying institute of Hainan Haikou China institute of geomechanics Chinese Academy of Geological Sciences Beijing China beijing Center of SHRIMP Beijing China institute of geology Chinese Academy of Geological Sciences Beijing China

The petrological and geochemical features of the bed parallel granitic intrusion in the Pre-Cambrian Baoban group in Hainan Island attest to the anatexis origin of the granites. U-Pb dating analyses of zircons from the anatectic granite and the biotite two-feldspar gneiss in the Baoban group, using SHRIMP II in the beijing Ion-probe Center, acquire 2.6Pb/2.8U ages of 368±3.5 Ma (of granite, 95% confidence level, MSDW=1.2.) and 362.9±6.1 Ma (of gneiss, 95% confidence level, MSDW = 2.04. respectively. The two late Devonian ages indicate consistently a tectonic- thermal event experienced in Hainan Island, and are the first discovered record of the Devonian geological process in the district. This event possibly resulted from the deep ther-mal-dynamic process when the Gondwana continent began to break up in the Devonian period.

关键词： Hainan Island, Devonian period, anatectic granite, zircon SHRIMP U-Pb dating.

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