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Zircon shrimp geochronology of the Xinkailing-Kele complex in the northwestern Lesser Xing'an Range,and its geological implications

中国科学院地质与地球物理研究所2004学术年会

作者： SHI Guanghai~1,MIAO Laicheng~1,ZHANG Fuqing~1, JIAN Ping~2,FAN Weiming~1 & LIU Dunyi~2 1.institute of geology and Geophysics.chinese academy of sciences. beijing 100029,china 2.shrimp lab,institute of geology,chinese academy of geological sciences,beijing 100037,china

A new rock type of granite,approximate 45 km in area and located about 10 km south of Xilinhot,Inner Mongolia,was found in the Sunitezuoqi(or called Suzuoqi) -Xilinhot tectonic belt and identified as an A-type miarolitic *** pluton has miarolitic structure and is composed chiefly of perthite,quartz,euhedral albite and potassium *** types of textures occur in the pluton,such as perthitie,graphic and myrmekite textures. Only quartz is found in miarolitic *** A-type granite with seagull-shaped REE patterns and obvious negative Eu anomaly(δEu=0.24—0.28) is high in SiO(76%—77%),K and Na(NaO+KO=7.75%—8.15%) and low in Ca(CaO =0.20%—0.22%),Fe and *** petrographical observations and chemical compositions indicate that it is an A-type *** shrimp U-Pb analyses indicate that this A-type granite was emplaced at 276±2 Ma and coeval with the same type of granites in the adjacent ***,it suggests that this pluton was likely formed in a post-orogenic extensional setting and probably related to break-off of subducted slabs in Central Asian Orogenic Belt(CAOB),which indicate that the Sunitezuoqi-Xilinhot belt was tectonically evolved into post-orogenic stage since early Permian.

关键词： A-type miarolitic granite shrimp Xilin Gol Inner Mongolia

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Zircon SHRIMP geochronology of the Xinkailing-Kele complex i...

^(40)Ar/^(39)Ar dating of shear deformation of the Xianshuihe fault zone in west Sichuan and its tectonic significance

中国科学院地质与地球物理研究所2004学术年会

作者： MIAO Laicheng~1,FAN Weiming~1,ZHANG Fuqing~1, LIU Dunyi~2,JIAN Ping~2,SHI Guanghai~1,TAO Hua~2 & SHI Yuruo~2 1.institute of geology and Geophysics,chinese academy of sciences, beijing 100029,china 2.shrimp lab,institute of geology.chinese academy of geological sciences,beijing 100037,china

Located in the eastern portion of the Xing’an-Mongolian Orogenic Belt(XMOB),the Xinkailing-Kele complex has previously been considered to be Precambrian metamorphic rocks,mainly according to its relatively high metamorphic *** filed observation,however,revealed that the complex is composed mainly of metamorphic rocks(Kele complex),tectono-schists("Xinkailing Group"), and granitoids(Xinkailing granitic complex).Dating on these rocks using advanced shrimp zircon U-Pb technique indicates that:(1) Biotite-plagioclase gneiss from the Kele complex has a protolith age of 337±7 Ma(2σ) and a metamorphic age of 216±3 Ma(2σ);(2) the tectono-schist of the"Xinkailing Group"gave a magmatic age of 292±6 Ma(2σ),indicative of felsic volcanic protolith of the schist formed in Late Paleozoic time;and(3) the Menluhedingzi and Lengchuan granites of the Xinkailing granitic complex were emplaced at 167±4(2σ) and 164±4 Ma(2σ),*** results suggest that the Xinkailing-Kele complex is not Precambrian metamorphic rocks and the so-called Precambrian"Nenjiang Block"does essentially not *** combination with regional geological data,we propose that the Kele metamorphic complex is likely related to a collisional tectonism that took place in Triassic time,as indicted by its metamorphic age of 216±3 *** Xinkailing granitic complex was emplaced along the collisional zone during Mid-Jurassic time, likely in a post-orogenic or anorogenic setting.

关键词： zircon shrimp geochronology Xinkailing-Kele complex Lesser Xing’an Range

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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, chinese academy of geological sciences, beijing 100081, china 2. institute of geology, chinese academy of geological sciences, beijing 100037, china 3. institute of geology and Geophysics, chinese academy of sciences, beijing 100029, china institute of Geomechanics Chinese Academy of Geological Sciences Beijing 100081 China institute of geology Chinese Academy of Geological Sciences Beijing 100037 China institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 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, 40Ar/39Ar dating, late Cenozoic.

Discovery of the budding phosphatized globular fossils from the Neoproterozoic Doushantuo Formation at Weng'an, Guizhou Province, china

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Progress in Natural Science:Materials International 2006年第10期16卷 1079-1083页

作者： LIU Pengju , YIN Chongyu and TANG Feng (institute of geology, chinese academy of geological sciences, beijing 100037, china) [a]institute of geology Chinese Academy of Geological Sciences Beijing China

There is much debate on biological affinities of the phosphatized globular fossils from the Neoproterozoic Doushantuo phosphorites at Weng’an, Guizhou Province. Here we report for the first time the budding structures of some of these globular fossils, which have previously been interpreted as the resting eggs and early cleavage embryos of metazoans. The budding structures are similar to the germinating tubes of the spore and zygote of living algae, suggesting that some globular fossils from the Doushantuo phosphorites bear affinity with algae. The present new information indicated various biological affinity of the phosphatized globular fossils from the Doushantuo phosphorites.

关键词： Neoproterozoic Donshantuo Formation globular fossil budding structure algae resting eggs embryos.

Genetic Mechanism of Mineral Inclusions in Zircons from the Khondalite Series, Southeastern Inner Mongolia

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Acta Geologica Sinica(English Edition) 2003年第1期77卷 28-35页

作者： LIU Fulai and SHEN Qihan institute of geology, chinese academy of geological sciences, beijing 100037 chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

The early Precambrian khondalite series is widely distributed in theJining-Zhuozi-Fengzhen-Liangcheng area, southeastern Inner Mongolia. The khondalite series mainlyconsists of sillimanite garnet potash feldspar (or two-feldspar) gneiss and garnet biotiteplagioclase gneiss. These gneissic rocks have commonly experienced granulite-facies metamorphism. Inzircons separated from sillimanite garnet potash feldspar gneisses, many mineral inclusions,including Sil, Grt, Ky, Kfs, Qtz and Ap, have been identified by the Laser Raman ***, prograde metamorphic mineral inclusion assemblages such as Ky + Kfs + Qtz + Ap and Ky +Grt + Kfs + Qtz are preserved in the core of zircon, while peak granulite-facies metamorphicminerals including Sil + Grt + Kfs + Qtz and Sil + Gif + Kfs + Qtz + Ap are identified in the mantleand rim of the same zircon. However, in some zircons are only preserved the peak metamorphicminerals such as Sil + Grt + Kfs + Qtz and Sil + Grt + Kfs + Qtz + Ap from core to rim, and inothers are inherited the primary cores with minor mineral inclusions of Kfs + Qtz, with peakmetamorphic mineral inclusions around the inherited cores. These data indicate that the mineralassemblage evolution of sillimanite garnet potash feldspar gneisses in the study are did experiencea polymorphic transformation of kyanite to sillimanite. In garnet biotite plagioclase gneisses,secondary electron microscopic images reveal that most zircons display distinct zoning textures,which comprise cores and rims, each with distinctive inclusion assemblages. The inherited mineralinclusions, mainly consisting of Kfs + Pl + Qtz, Kfs + Qtz and Kfs + Qtz + Ap, are preserved in theprimary cores, while peak granulite-facies mineral asemblages, including Grt + Bt + Pl + Qtz + Ap,Grt + Bt + Pl + Qtz and Grt + Bt + Pl + Qtz + Rt, are identified on the rims. The occurrence of peakmetamorphic mineral inclusions in zircons indicates that these gneissic rocks, includingsillimanite garnet potas

关键词： mineral inclusion zircon Laser Raman secondary electron microscopy genetic mechanism khondalite series Inner Mongolia

Mineralization episode of porphyry copper deposits in the Jinshajiang-Red River mineralization belt: Re-Os dating

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Science china Earth sciences 2005年第2期48卷 192-198页

作者： WANG Denghong, QU Wenjun, LI Zhiwei, YIN Hanlong4 & CHEN Yuchuan institute of Mineral Resources, chinese academy of geological sciences, beijing 100037, china National Center of Rock and Mineral Analysis, chinese academy of geological sciences, beijing 100037, china Resource Assessment Center of Yunnan, Kunming 650011, china institute of geology and Geophysics, chinese academy of sciences, beijing 100101, china chinese academy of geological sciences, beijing 100037, china 1. institute of Mineral Resources Chinese Academy of Geological Sciences 100037 Beijing China 2. National Center of Rock and Mineral Analysis Chinese Academy of Geological Sciences 100037 Beijing China 3. Resource Assessment Center of Yunnan 650011 Kunming China 4. institute of geology and Geophysics Chinese Academy of Sciences 100101 Beijing China 5. chinese academy of geological sciences 100037 Beijing China

Re-Os isotopic dating for the molybdenites from the porphyry copper deposits of the Jinshajiang-Red River mineralization belt in Yunnan Province yields isochron ages of 33.9±1.1 Ma for the Machangqing deposit and 34.4±0.5 Ma for the Tongchang deposit. This result shows that both the Machangqing and the Tongchang porphyry Cu-Mo deposits from two different ore-fields formed simultaneously. This new data and the published Re-Os model ages of molybdenite (35.4 Ma, 35.9 Ma, 36.2 Ma) of the Yulong porphyry copper deposit in Tibet, which is located in the same Jinshajiang-Red River mineralization belt as the Machangqing deposit and the Tongchang deposit, suggest that these three Cenozoic porphyry copper deposits in the Jinshajiang-Red River mineralization belt were contemporary for their mineralization episode. That is to say, even their present locality is far away and nearly iso-distantly distributed, these three porphyry Cu(Mo) deposits belong to the same mineralization episode at the end of Eocene.

关键词： Re-Os isotopic dating, porphyry Cu deposits, Cenozoic, mineralization episode.

Megaclasts from the Carboniferous-Permian Rocks in the Langkawi Islands, Malaysia, and Their Implications

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Acta Geologica Sinica(English Edition) 1999年第1期73卷 120-122页

作者： Chen Tingyu institute of geology 26 Baiwanzhuang Road,chinese academy of geological sciences, beijing 100037,china institute of geology 26 Baiwanzhuang Road Chinese Academy of Geological Sciences Beijing 100037 China

The Ninth Regional Congress on geology, Mineral andEnergy Resources of Southeast Asia was held in KualaLumpur of Malaysia in August of 1998. After the Con-gress, the author participated in the geological fieldexcursion and investigation in the Langkawi Islands,and noted that the Carboniferous-Permian rocks con-tain megaclasts of metamorphic and pegmatitic rocks,which indicate the existence of pre-Carboniferousmetamorphism and magmatism. The observation resultsare as follows:

关键词： Malaysia and Their Implications Megaclasts from the Carboniferous-Permian Rocks in the Langkawi Islands

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 institute of Geochemistry, chinese academy of sciences, Guangzhou 510640, china 2. Graduate University of chinese academy of sciences, beijing 100039, china 3. shrimp isotope laboratory, chinese academy of geological sciences, beijing 100037, china 4. institute of geology and Geophysics, chinese academy of sciences, beijing 100029, 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 (02DX-137) and southern (20JH-10) Lincang batholith show the single and tight clusters on the concordia, and yield the weighted mean 206Pb/238U ages of 229.4 ± 3.0 Ma and 230.4 ± 3.6 Ma, respectively, representing the crystallized ages of these granites. The zircons for the rhyolitic sample (02DX-95) from the Manghuai Formation give a weighted mean 206Pb/238U age of 231.0 ± 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 (~230 Ma) and were originated from the postcollisional tectonic regime. An early Proterozoic 206Pb/238U apparent age of 1977±44 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.

Early-Middle Permian Reef Frameworks and Reef-building Models in the Eastern Kunlun Mountains

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Acta Geologica Sinica(English Edition) 2001年第2期75卷 115-125页

作者： TIAN Shugang institute of geology, chinese academy of geological sciences, beijing 100037and FAN Jiasong institute of geology and Geophysics, chinese academy of sciences, beijing 100029 institute of geology Chinese Academy of Geological Sciences Beijing 100037 institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 [?]3Tian Shugang Born in September 1951 graduated from beijing University in 1977 and received his MS. and Ph. D. degrees at china University of Geosciences (beijing) in 1985 and 1988 respectively working now in the institute of geology Chinese Academy of Geological Sciences. He has long been engaged mainly in studies of biostratigraphy palaeoecology sequence-stratigraphy and reefs. Tel: 010–68328223 E-Mail: sgtian2001@***

Reef frameworks and building models of the Early-Middle Permian in the eastern Kunlun Mountains have been verified through studies of reef-building communities, palaeoecology and carbonate facies. The eastern Kunlun reefs are built mainly by 6 reef-building communities, which include 11 major categories of frame-building organisms and 6 categories of reef-associated organisms. Eight types of reef-frames have been distinguished and eleven kinds of rocks identified to belong to 6 reef facies. Three sorts of reefs classified by previous researchers, namely mudmounds, knoll reefs and walled reefs, are well developed in the study area. Such reef-facies association and reef distribution show that there are 4 models of reef growth and development, i.e. the tidal-bank knoll-reef model, the plateau-margin wall-reef model, the composite wall-reef model and the deep-water mudmound model. The reefs are mainly constructed by calcareous sponge and calcareous algae, which are similar to all Permian reefs in other area

关键词： reef model Early-Middle Permian eastern Kunlun reefs