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Zircon and apatite fission track analyses on mineralization ages and tectonic activities of Tuwu-Yandong porphyry copper deposit in northern Xinjiang, China

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Science China Earth sciences 2007年第12期50卷 1787-1795页

作者： YUAN WanMing1,BAO ZengKuan2,DONG JinQuan2,GUO ZhaoJie3.& DENG Jun1 1 State Key Laboratory of geological Processes and Mineral Resources,China University of Geo{1.,beijing100083.China 2 Laboratory of Nuclear Analysis Techniques,{3. of High Energy Physics,chinese academy of {1.,beijing 1.003.,China 3.Department of geology,Peking University,beijing 100871,China 1. State Key Laboratory of geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China 2. Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039 China 3. Department of {1. Peking University Beijing 100871 China

The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian *** study has achieved 9 zircon and 7 apatite fission track analysis *** zircon fission track ages range from 1.8 Ma to 289 Ma and the apatite ages are between 64 Ma and 1.0 *** mineralization accords with the regional tectonics in the copper *** consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 1.0―3.0℃ and retention temperature of ～250℃ for zircon fission track,and metallogenetic temperature of 1.0―3.0℃ in this ore *** three mineralization epochs have been identified,i.e.,289―276 Ma,23.―200 Ma and 1.5―1.8 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan *** to apatite fission track ages,the three tectonic-mineralizing epochs are 1.0―1.0} Ma,1.9―97 Ma and 64 Ma,which means age at about 1.0℃ after the *** three epochs lasted 1.6 Ma,1.8 Ma and about 1.0 Ma from ～250℃ to ～1.0℃ and trend decrease from early to *** is shown by the fission track modeling that this district underwent three stages of geological thermal histories,stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.

关键词： mineralization age, tectonic epoch, fission track, zircon, apatite, Tuwu-Yandong, Xinjiang

The crystal structure of (Fe_(4)Cr_(4)Ni)_(9)C_(4)

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Science China Earth sciences 2005年第3期48卷 338-345页

作者： SHI Nicheng1. MA Zhesheng1. XIONG Ming1. DAI Mingquan1. BAI Wenji2, FANG Qingsong2, YAN Binggang2 & YANG Jingsui2 1. X-ray Diffraction Laboratory, China University of Geosciences, {1. 1.0083. China 2. institute of geology,{3., beijing 1.003., China 1. X-ray Diffraction Laboratory China University of Geosciences 100083 Beijing China 2. institute of geology Chinese Academy of Geological Sciences 100037 Beijing China

(Fe4Cr4Ni)9C4 is a metal carbide mineral formed by combination of Fe, Cr and Ni with C. It occurs in a chromite deposit in the Luobusha ophiolite, Tibet. Based on the determina- tion of its crystal structure, the empirical formula is (Fe4.1.Cr3.84Ni0.96)8.92C3.70 and the simplified formula is (Fe4Cr4Ni)4C9. The mineral is hexagonal with a = 1.3.3.2(2) nm, c = 0.44690(9) nm, space group P63.m c, Z=6 and the calculated specific gravity Dx = 7.089 g/cm3. Fe, Cr and Ni occupy different crystallographic sites and their coordination numbers are approximately 1., forming an alternate stacking sequence of flat and puckered layers along the c axis. Some me- tallic atoms have a defect structure. The interatomic distances of Fe, Cr and Ni are 0.2525— 0.2666 nm, and the distances between Fe, Cr, Ni and C are 0.1.93.0.21.9 nm. The coordina- tion number of carbon is 6. It occurs in interstices of the metallic atoms Fe, Cr and Ni to form trigonal-prismatically coordinated polyhedra. These coordination polyhedra are linked with each other via shared corners or shared edges into a new type of metal carbide structure.

关键词： Luobusha of Tibet, metal carbide, crystal structure.

Tectonic setting of the Helong Block:Implications for the northern boundary of the eastern North China Craton

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Science China Earth sciences 2005年第10期48卷 1599-1612页

作者： ZHANG Yanbin1. WU Fuyuan1. ZHAI Mingguo1.& LU Xiaoping1.2 1. institute of geology and Geophysics, {1. academy of {3., P.O. Box 9825, beijing 1.0029, China 2. Regional geological and Mineral Resources Survey of Jilin Province, Changchun 1.3}062, China institute of {1. and Geophysics chinese {3. of sciences beijing China Regional geological and Mineral Resources Survey of Jilin Province Changchun China

LA-ICP-MS zircon U-Pb dating indicates that the Bailiping granitic pluton was em-placed during Late Paleozoic to Early Cretaceous (285―1.6 Ma) by four distinct magmatic epi-sodes, arguing against the previous thought that the Bailiping granites were emplaced during Archean, Proterozoic or Early Paleozoic. It is suggested that the so-called Archean Jincheng-dong granite-greenstone belt, mainly composed of Bailiping granites, should be broken down. Sr-Nd isotopic compositions of the Bailiping granites are similar to those of the Phanerozoic granites in the Xing’an-Mongolian orogenic belt, suggesting that their parental magmas were mainly derived from a juvenile crust with some contamination of ancient crustal materials during magma rising and/or emplacement. Therefore, the basement of the Helong Block is similar to that in the northern Xing’an-Mongolian Orogenic Belt, but different from that of the North China Craton. It is proposed that the Archean Jinchengdong complex in this area is probably an exotic slice from the North China Craton, which indicates that the Fu’erhe-Gudonghe Fault, located in northern part of the Helong area, is not the boundary between the North China Craton and the Xing’an-Mongolian Orogenic Belt. The possible boundary should be located further southward more than 50 km and near the Baitoushan volcano.

关键词： LA-ICPMS ziron U-Pb dating, Bailiping complex, Helong Block, North China Craton, Sr-Nd isotope.

^(1.)C measurement of forest soils in Dinghushan Biosphere Reserve

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chinese Science Bulletin 1999年第3期44卷 251-256页

作者： SHEN Chengde , LIU Dongsheng (LIU Tungsheng) , PENG Shaolin, SUN Yanmin , JIANG Mantao , Yl Weixi , XING Changping , GAO Quanzhou , LI Zhi’an and ZHOU Guoyi Guangzhou institute of Geochemisry, {1. academy of {3., Guangzhou 51.640, China institute of geology, {1. academy of {3. , beijing 1.0029, China South China institute of Botany, {1. academy of {3., Guangzhou 51.650, China Guannzhou institute of Geochemisry Chinese Academy of Sciences Guanazhou China institute of {1. Chinese Academy of Sciences Beijing China South China institute of Botany Chinese Academy of Sciences Guangzhou China

Organic carbon in forest soils of Qingyunsi and Wukesong profiles can be divided into fast and slow components. Δ1.C values of these profiles decrease with increasing of depth. The Δ1.C values in 3.—40 cm depth interval of Wukesong profile are decreasing sharply until a very low value,showing that a strong {1. environment change occurred about 1.560 years ago. The 1.C apparent ages of Wukesong profile show that the coniferous and broad-leaf mixed forests around Wukesong profile have been developing since 425 a BP, which is consistent with historical documents. The penetrating depths of "bomb 1.C" in Qingyunsi and Wukesong profiles are 1. and 20 cm, respectively.

关键词： Dinghushan forest soil 1.C tracing 1.C apparent age.

Permian Alkaline Granites in Central Inner Mongolia and Their Geodynamic Significance

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Acta Geologica Sinica(English Edition) 1995年第1期69卷 27-39页

作者： Hong Dawei, Huang Huaizeng, Lithosphere Research center,{1., beijingXiao Yijun,{3.,{1., beijingXu Haiming,institute of Mineral Deposits,{1., beijingand Jin M anyuanTianjin geological {1.}, Ministry of Metallurgical Industry, Tianjin Fei Zhenbi Lithosphere Research center Chinese Academy of Geological Sciences Beijing China

Alkaline granites (Rb-Sr ages 276-286 Ma)occurring in the Bayan Ul-East Ujimqin belt at the southern margin of the Siberian plate originated in a tensional tectonic environment about 60 Ma earlier than the Late Devonian to Early Carboniferous collision between the Siberian and Sino-Korean plates. They belong to post-orogenic A-type granites and may be used as an indicator of the end of the orogeny. At the northern margin of the Sino-Korean plate, however, only late-orogenic calc-alkaline granites occurred during the late Caboniferous-Permian, and alkaline syenites did not appear until the Late Triassic. The asymmetric magmatism at the margins of the two neighbouring plates might be controlled by the differences in size and mass of the two plates.

关键词： alkaline granite geodynamics Inner M ongolla

geological EVOLUTION AND OROGENY OF EAST KUNLUN TERRAIN ON THE NORTHERN QINGHAI—TIBET PLATEAU

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地学前缘 2000年第S1期7卷 234-235页

作者： Xu Zhiqin, Yang Jingsui, Li Haibing(institute of {1., chinese academy of geological sciences,{3.,China)

The East Kunlun terrain is located on the northern Qinghai—Tibet plateau, composed of the East Kunlun Mountain and the Qaidam Basin and bounded by the Qilian terrain on the north and Bayanhar—Songpan Ganze terrain on the south. It is regarded as a composite orogenic belt characterized by having developed superimposed ductile tectonic regimes reflecting the collision orogeny during Early Paleozoic and Triassic periods. It has also experienced transformation from ductile to brittle deformation caused by the post orogeny, since Jurassic after the formation of the East Kunlun Mountain and the Qaidam Basin. A Paleozoic subduction complex zone was recently recognized along the north border of the East Kunlun terrain from Da Qaidam to Dulan (Xu,et al, 1.999). It is composed of ophiolite (of Early Paleozoic age?), tectonic melange and very high\|pressure metamorphic rocks with eclogite (\%p\%=2 2GPa, \%t\%=720℃) (Yang,et al.,1.98) and garnet\|peridotite (\%p\%=2 5GPa, t =83.℃). The Anyemaqin Triassic subduction complex zone trending in NWW\|SEE was developed along the eastern segment of the south border of the East Kunlun terrain. It is mainly composed of ultramafic and mafic rocks, pillow basalt, radiolaria\|bearing clastic rocks, tectonic melange and mylonite. The subduction complex zone contains a series of the southward overthrusting imbricated slices. Instead of this subduction complex zone, a 2 km\|wide sinistral strike\|slip ductile shear zone trending in E\|W was developed along the western segment. On the basis of macroscopic and microscopic studies on a series of structural sections, we divide the East Kunlun Mountain into four tectonic units as follows: (1. North Proterozoic Metamorphic Basement Zone; (2) South Early Paleozoic—Triassic Superimposed Fold Zone; (3. South Triassic Transpression Zone; (4) Anyemaqin Back\|Arc Decollement\|Thrust Zone.

关键词： East Kunlun terrain composite orogenic belt subduction compl ex zone transpression shear zone

PALEOMAGNETIC ESTIMATE OF THE MESOZOIC—CENOZOIC LATITUDINAL DISPLACEMENT OF TERRENES IN THE QINGHAI—TIBET PLATEAU AND ITS SIGNIFICANCE

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地学前缘 2000年第S1期7卷 325-326页

作者： Li Pengwu, Cui Junwen, Li Li(institute of {1., chinese academy of geological sciences,{3., China)

The Mesozoic—Cenozoic latitudinal displacement amounts of terranes (or blocks) in the Qinghai—Tibet plateau were calculated in paleomagnetism. These terranes (or blocks) include Tarim and Qaidam blocks, East Kunlun, Baryan Har, Qiangtang, Lhasa and Himalaya terranes. The calculated results are listed in table 1. These results show that:(1. There was the latitudinal displacement difference between central area and southwestern area in the Tarim southern margin since the lower Cretaceous. There was a southward latitudinal movement from the beginning of middle Jurassic or upper Jurassic (Zhou Qingjie, 1.92). The northward movement amounts of the Tarim northern margin since the Paleocene are greater than that of the Tarim southern margin. Tarim southern margin has moved northward about 1.00km since the Paleocene, Tarim northern margin has done about 1.00km. Qaidam has moved northward about 3.00km since lower\|middle Jurassic. The northward displacement amount of Qaidam since Paleocene is about 81.km, near to that of the central area, Tarim southern margin.

关键词： Qinghai\|Tibetan plateau paleomagnetism latitudinal displacement

Carbon and hydrogen isotopic characteristics of natural gases from the Luliang and Baoshan basins in Yunnan Province, China

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Science China Earth sciences 2006年第9期49卷 938-946页

作者： XU Yongchang1. LIU Wenhui2, SHEN Ping1. WANG Wanchun1. WANG Xiaofeng1. Tenger1. YAN Yaomin3.& LIU Ruobin3.1. Lanzhou center of Oil & Gas Resources,{1. and Geophsics, chinese {3. of sciences, Lanzhou 73.000, China 2. Research institute of Petroleum Exploration and Production, SINOPEC, beijing 1.0083. China 3. South Branch of Petroleum Exploration and Production Company, SINOPEC, Kuming 650000, China 1. Lanzhou center of Oil & Gas Resources Institute of Geology and Geophsics Chinese Academy of Sciences Lanzhou 730000 China 2. Research institute of Petroleum Exploration and Production SINOPEC Beijing 100083 China 3. South Branch of Petroleum Exploration and Production Company SINOPEC Kuming 650000 China

The Luliang and Baoshan basins of Yunnan Province are two small-sizedcontinental oil/gas-bearing sedimentary basins, which were developed at the bases of theCarboniferous and Devonian systems during the Late Tertiary, covering an area of 3.5 km^2 and 254km^2, respectively. Since the 1.90s, there have been discovered small-sized natural gas pools inthese two basins. The natural gases are composed mainly of hydrocarbon gases, with nonhydrocarbonsaccounting for less than 2%. Of the hydrocarbon gases, methane accounts for more than 99%, and thecomponents above C_2 account for less than 0.2%. On the basis of previous studies of {1.background, the composition of natural gases and their carbon isotopic composition, it has beendefined that these two gas pools are of bacterial origin. In this work we have comprehensivelymeasured the carbon and hydrogen isotopic composition of natural gases from these two basins andhave gone into the details of the mechanism of gas generation. The δ^(1.0}C_1.values of naturalgases from the Luliang Basin are within the range of -72.1.per thousand - -73.3.per thousand, andthe δD_(CH_4) values, -242 per thousand - -23. per thousand, indicating that the bacterial gasgeneration is dominated by the way of CO_2 reduction. It has been evidenced that undercontinental-facies fresh water conditions there did occur the CO_2 reduction as a process ofbacterial gas generation. The δ^(1.0}C_1.values of natural gases from the Baoshan Basin are withinthe range of - 62.5 per thousand - -63.5 per thousand, and the δD_(CH_4) values, -252 per thousand- -260 per thousand. These isotopic characteristics are fallen into transitional phase of acetatefermentation and CO_2 reduction as defined by Whiticar et al. (1.86). An important discovery in theLuliang Basin is the carbon isotopic composition of ethane of purely biogenetic origin, i.e., itsδ^(1.0}C_2 values are within the range of - 61.2 per thousand - - 66.0 per thousand. These carbonisotopic values have been r

关键词： bacterial gas, carbon and hydrogen isotope, CO2 reduction, acetate fermentation.

The possible contribution of a mantle-derived fluid to the Ningwu porphyry iron deposits—Evidence from carbon and strontium isotopes of apatites

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Progress in Natural Science:Materials International 2008年第2期18卷 167-172页

作者： Jinjie Yu ,Jingwen Mao,Changqing Zhang institute of Mineral Resources,{1. academy of {3. Science,beijing 1.003.,China institute of Mineral Resources Chinese Academy of Geological Science Beijing 100037 China

Apatite is a characteristic mineral for the iron deposits in the Ningwu region. Apatite shows a range of d1.0}PDB values from à9.6& to à0.6&,and most of them with the d1.0}PDB values distributed in a range of mantle carbon (i.e.,à2& to à9&),except for samples T-06-1.and J-06-3. Apatites in the Ningwu porphyry iron deposits yield a narrow variation range of 87Sr/86Sr values from 0.7063.6 to 0.707577,similar to those of the volcanic and subvolcanic rocks and higher than that of a typical mantle-derived magmatic apatite (i.e.,about 0.7040),indicating that formation of the apatites was involved with crust material contamination. d1.0}PDB and 87Sr/86Sr values of the apatite indicate a possible contribution of mantle-derived fluid and material to formation of the Ningwu porphyry iron deposits,supported by regional geology,regional gravities and geochemistry of the volcanic and subvolcanic rocks in the Ningwu region.

关键词： Apatite 87Sr/86Sr ratios Fluid inclusion d1.0} Mantle fluid and material