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Carboniferous Post-collisional Rift Volcanism of the Tianshan Mountains, Northwestern china

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Acta Geologica Sinica(English Edition) 2003年第3期77卷 338-360页

作者： XIA Linqi, XU Xueyi, XIA Zuchun, LI Xiangmin, MA Zhongping and WANG Lishe Xi’an institute of Geology and mineral resources,{3., Xi’an, Shaanxi 710054 E-mail: geologyx@***. Liu Shuchun and Liu Xinzhu Xian Inst Geol & mineral resources China Geol Surv Xian 710054 Shaanxi Peoples R China

The Tianshan Carboniferous post-collisional rift volcanic rocks occur in northwestern china as a large igneous province. Based on petrogeochemical data, the Tianshan Carboniferous post-collisional rift basic lavas can be classified into two major magma types: (1) the low-Ti/Y type situated in the eastern-central Tianshan area, which exhibits low Ti/Y (3.55%), and relatively high Fe2O3. (6.4-11.5%); (2) the high-Ti/Y type situated in the western Tianshan area, which has high Ti/Y (>500), Ce/Yb (>11) and SiO2 (49-55%), and relatively low Fe2O3. (5.8-7.8%). Elemental data suggest that chemical variations of the low-Ti/Y and high-Ti/Y lavas cannot be explained by fractional crystallization from a common parental magma. The Tianshan Carboniferous basic lavas originated most likely from an OIB-like asthenospheric mantle source (87Sr/86Sr(t) ≈ 0.703.0.705, eNd(0 = +4 to +7). The crustal contamination and continental lithospheric mantle have also contributed significantly to the formation of the basic lavas of the Tianshan Carboniferous post-collisional rift. The silicic lavas were probably generated by partial melting of the crust. The data of this study show that spatial petrogeochemical variations exist in the Carboniferous post-collisional rift volcanics province in the Tianshan region. Occurrence of the thickest volcanics dominated by tholeiitic lavas may imply that the center of the mantle-melting anomaly (mantle plume) was in the eastern Tianshan area at that time. The basic volcanic magmas in the eastern Tianshan area were generated by a relatively high degree of partial melting of the mantle source around the spinel-garnet transition zone, whereas the alkaline basaltic lavas are of the dominant magma type in the western Tianshan area, which were generated by a low degree of partial melting of the mantle source within the stable garnet region, thus the basic lavas of the western Tianshan area might have resulted from relatively thick li

关键词： Carboniferous post-collisional rift volcanics geochemistry petrogenesis asthenosphere lithosphere Tianshan Mountains NW china

Re-Os(ICP-MS)dating of the massive sulfide ores from the Jinchuan Ni-Cu-PGE deposit

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Science china Earth Sciences 2005年第10期48卷 1672-1677页

作者： YANG Gang1,2, DU Andao1, LU Jiren3. QU Wenjun1 & CHEN Jiangfeng2 1. National Research Center of Geoanalysis, Beijing 10003., china 2. Laboratory for Earth Material Cycling, School of Earth and Space Sciences, University of Science and Technology of china, Hefei 23.026, china 3. {3. of mineral Resource, Chinese Academy of geological Sciences, Beijing 10003., china National Research Center of Geoanalysis University of Science and Technology of china Chinese Academy of geological Sciences

Massive sulfide ore from the Jinchuan Ni-Cu-PGE deposit was dated by Re-Os technique using Carius Tube digestion, Os distillation, Re extraction by acetone and ICP-MS measurement. An isochron giving an age of 83. ± 3. Ma, initial 187Os/188Os ratio of 0.279 ± 0.018 (MSWD = 1.7) and γOs = 13. ± 15 is obtained. The Re-Os age obtained agrees, within analytical uncertainties, with previous SHRIMP zircon U-Pb age of 827 ± 8 Ma (n=5, MSWD = 4.3.. The result suggests that the deposit was formed at Neoproterozoic and that the formation of the Jinchuan Ni-Cu-PGE sulfide deposit may be closely related to the plume activity, which were attributed to the breakup of the Rodinia supercontinent. The high γOs of the massive ores sug-gests that crustal material was involved in the formation of the Jinchuan deposit, however, the quantity of the added crustal material is less than 10%.

关键词： Jinchuan Ni-Cu-PGE deposit, Re-Os dating, ICP-MS.

SHRIMP Zircon U-Pb Ages and Geochemical Characteristics of the Neoproterozoic Granitoids in the Huangling Anticline and Its Tectonic Setting

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Journal of Earth Science 2012年第5期23卷 659-675页

作者：魏运许彭松柏蒋幸福彭中勤彭练红李志宏周鹏曾雄伟 Wuhan institute of Geology and minerals resources Wuhan Center of Geological Survey Faculty of Earth Sciences China University of Geosciences Three Gorges Research Center for Geo-hazard Ministry of EducationChina University of Geosciences State Key Laboratory of geological Processes and mineral resources China University of Geosciences

SHRIMP zircon U-Pb dating of the Neoproterozoic Maoping （茅坪） series （Sandouping （三斗坪） rock suite） granites exposed in the southern part of the Huangling （黄陵） anticline shows that the formation time of Sandouping biotite-hornblende tonalite intrusion, Jinpansi （金盘寺） hornblende-biotite tonalite intrusion, and Longtanping （龙潭坪） monzogranite are 863.9, 842±10, and 844±10 Ma, respectively. Their geochemical features include A/CNK=0.98-1.06, from metaluminous to weakly peraluminous, δ=1.3.-1.53. Sm/Nd=0.17-0.24, and RbN/YbN=1.1-3.62. These indicate that the granite rocks are supersaturated SiO2 calc-alkaline granitoids. The characteristic of Sr-Nd isotopic composition is that the values of εNd（t） and εsr（t） are -12.4 to -11.0 and 20.2-3..2, respectively. It also suggests that the material source of the granite rocks mainly originated from the crust, and they formed in a volcanic arc tectonic environment. These facts suggest that the occurrence of Neoproterozoic granitoids in the southern part of the Huangling anticline should be related to an arc environment along an active continental margin caused by southward subduction of oceanic crust beneath the northern Yangtze craton, and the formation age is not later than 863.Ma.

关键词： Huangling anticline Yangtze plate Neoproterozoic granitoid SHRIMP zircon U-Pbdating geochemistry tectonic setting.

Lead Isotope Studies of Massive Surphur-Iron-Gold Deposits in the Tongling Area, Anhui Province

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Acta Geologica Sinica(English Edition) 1992年第2期66卷 177-189页

作者： Huang Bin Research institute of Geology and mineral resources,{3. National Nonferrous Metals Industry Corporation. Guilin, Guangxi Sun Sheping Research institute of Geology and mineral resources China National Non ferrous Metals Industry Corporation Guilin Guangxi

Pb isotope ratios and their variation have been measured and explained on ores of massive S-Fe-Au depos-its hosted in the Middle-Upper Carboniferous, on feldspars from diorite bodies closely related tomineralization and on whole rocks from ore-hosting strata (carbonate rocks) in the Tongling area, Anhui Prov-ince. Through a comparison of Pb isotope features of these geological bodies, it has been suggested that oresubstances of the deposits were derived from ore-hosting strata. In the meanwhile, the measurement of ore Pbisotopes of different mineralization types of the same deposit indicates that different mineralization types havedistinct Pb isotope characteristics, showing the potentiality of the Pb isotopic method used in mineral explora-tion.

关键词： Pb Anhui Province Lead Isotope Studies of Massive Surphur-Iron-Gold Deposits in the Tongling Area Gold

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, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, china 2. Regional geological and {3. resources survey of Jilin Province, Changchun 13.062, china Chinese Academy of Sciences Regional geological and mineral resources {3. of Jilin Province

LA-ICP-MS zircon U-Pb dating indicates that the Bailiping granitic pluton was em-placed during Late Paleozoic to Early Cretaceous (285―116 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.

Criteria for defining and recognizing the various orders of sequences in outcrop sequence stratigraphy

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Science china Earth Sciences 2004年第7期47卷 618-629页

作者： WANG Xunlian Faculty of Earth Sciences and mineral resources, china University of Geosciences, Beijing 100083. china State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, china Faculty of Earth Sciences and mineral resources China University of Geosciences Beijing China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

The regional distribution in different depositional facies belts is here regarded as an important criterion for defining and recognizing the various orders of sequences. The third-order sequence is possibly global in nature, which may be discerned in different depositional facies belts in one continental margin and can be correlated over long distances, sometimes even worldwide. Commonly, correlation of subsequence (fourth-order sequence with time interval of 0.51.5 Ma) is difficult in different facies belts, although some of them may also be worldwide in distribution. A subsequence should be able to discern and correlate within at least one facies belt. The higher-order sequences, including microsequence (fifth-order sequence) and minisequence (sixth-order sequence), are regional or local in distribution. They may reflect the longer and shorter Milankovitch cycles respectively. Sequence and subsequence are usually recognizable in different facies belts, while microsequence and minisequence may be distinguished only in shallow marine deposits, but not in slope and basin facies deposits. A brief discussion is made on the essential conditions for correct identification of sequences, useful methods of study, and problems meriting special attention in outcrop sequence stratigraphy.

关键词： outcrop sequence stratigraphy, facies belt, sequence, subsequence, microsequence, minisequence, meter-scale cyclothem, Milankovitch cycle.

Syndepositional Fault Controlling on Depositional Filling of the Third Member of Shahejie Formation in Beitang Sag

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Journal of Earth Science 2009年第6期20卷 949-958页

作者：黄传炎王华肖敦清陈思王家豪廖远涛 Faculty of Earth resources China University of Geosciences State Key Laboratory of geological Processes and mineral resources China University of Geosciences Key Laboratory of Tectonics and Petroleum resources of Ministry of Education China University of GeosciencesWuhan Research institute of Exploration and Development PetroChina Dagang Oilfield Company

In the continental lake basin whose structures were extraordinarily active, tectonism is an important factor in controlling the sequence and the depositional filling of the basin. This article reports the assemble patterns of syndepositional fault in the third member of Shahejie （沙河街） Formation in Beitang （北塘） sag. The results show that the comb-shape fracture system and the fracture transformation zone were developed in Beitang sag. These assemble patterns obviously controlled the sand-body and spatial distribution of sedimentary system. However, the steep slope belt of fault terrace, the multistage slope belt and the low uplift gentle slope belt controlled the development of sequence styles. Analyses of the spatial-temporal relationship of the assemble pattern of syndepositional faults and the sedimentary system help predict the favorable exploration zone.

关键词： Beitang sag syndepositional fault structural slope break zone the third member of Shahejie Formation.

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,{3. University of Geosciences,Beijing100083.{3. 2 Laboratory of Nuclear Analysis Techniques,institute of High Energy Physics,Chinese Academy of Sciences,Beijing 10003.,{3. 3.Department of Geology,Peking University,Beijing 100871,{3. State Key Laboratory of geological Processes and mineral resources China University of Geosciences Beijing China Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing China Department of Geology Peking University Beijing 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 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 *** 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 140―3.0℃ and retention temperature of ～250℃ for zircon fission track,and metallogenetic temperature of 120―3.0℃ in this ore *** three mineralization epochs have been identified,i.e.,289―276 Ma,23.―200 Ma and 165―158 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan *** to apatite fission track ages,the three tectonic-mineralizing epochs are 140―13. Ma,109―97 Ma and 64 Ma,which means age at about 100℃ after the *** three epochs lasted 146 Ma,108 Ma and about 100 Ma from ～250℃ to ～100℃ 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

Cesium accumulation by bacterium Thermus sp. TibetanG7:hints for biomineralization of cesium-bearing geyserite in hot springs in Tibet,china

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Chinese Science Bulletin 2007年第19期52卷 2680-2686页

作者： WANG HaiLei1,2,3. ZHENG MianPing1,2,3.& HUANG XiaoXing4 1 institute of mineral resources, Chinese Academy of {3. Sciences (CAGS), Beijing 10003., china 2 R&D Center for Saline Lake and Epithermal Deposits, CAGS, Beijing 10003., china 3.Open Laboratory of Saline Lake Resourses and Environment, CAGS, Beijing 10003., china 4 Laboratory of Microbial resources, institute of Microbiology, Chinese Academy of Sciences, Beijing 100081, china institute of mineral resources Chinese Academy of Geological Sciences (CAGS) Beijing China R&D Center for Saline Lake and Epithermal Deposits CAGS Beijing China Open Laboratory of Saline Lake Resourses and Environment CAGS Beijing China Laboratory of Microbial resources Institute of Microbiology Chinese Academy of Sciences Beijing China

The bacterium Thermus sp. TibetanG7, isolated from hot springs in Tibet, china, was examined for the ability to accumulate cesium from solutions. Environmental conditions were simulated and the effects of pH, K+, Na+ and K+-regimes were then studied to determine the possible role of the bacterium in the formation of cesium-bearing geyserite around these hot springs. In despite of the inhibition of K+ and Na+, the bacterium Thermus sp. TibetanG7 revealed noticeable accumulation of cesium from solutions, with maximum accumulations of 53.49 and 40.41 μmol Cesium/g cell dry weight in Na+ and K+ inhibition experiments, respectively. The accumulation of cesium by this microorganism is rapid, with 40%―50% accumulated within the first 5 min. K+-deficient cells showed a much higher capacity of cesium accu- mulation compared with K+-sufficient cells. It is evident that the bacteria within the genus thermus play a significant role in the cesium assembly. The formation of cesium-bearing geyserite is also considered.

关键词：铯元素沉积物硅华生物矿化