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shrimp dating of the Bangong Lake SSZ-type ophiolite: Constraints on the closure time of ocean in the Bangong Lake-Nujiang River,northwestern Tibet

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chinese Science Bulletin 2007年第7期52卷 936-941页

作者： SHI RenDeng1,2 1 School of Earth and Space sciences, University of Science and Technology of china, Hefei 23.026, china 2 Institute of Geology,{3., Beijing 10003., china (email: shird@***) School of Earth and Space sciences University of Science and Technology of China Hefei China Institute of Geology Chinese Academy of Geological Sciences Beijing China

The Bangong Lake ophiolite is located in the westernmost part of the Bangong Lake-Nujiang River suture zone. It is a tectonic mélange consisting of numerous individual blocks of peridotite, pillowed and massive lavas and mafic dykes with SSZ-type ophiolitic geochemical affinity formed at the end of a Wilson circle. The shrimp U-Pb ages of the co-magmatic zircon domains from one gabbroic dyke (Sample 01Y-155) range from 162.5±8.6 Ma to 177.1±1.4 Ma with an average of 167.0±1.4 Ma (n = 12, MSWD = 1.2), suggesting that the subduction of the Bangong Lake Neo-Tethyan Ocean started before the Middle Jurassic. It is inferred that the tectonic transform from spreading to subduction of the Neo-Tethyan Ocean began before the Middle Jurassic in the Bangong Lake area.

关键词：西藏班公湖怒江缝合带古海洋闭合时期 SSZ型蛇绿岩 shrimp 测年

Analytical method of Cr stable isotope and its application to water pollution survey

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chinese Science Bulletin 2010年第7期55卷 664-669页

High Cr(VI) concentration is a potential serious risk to environment and ecologic ***,it is essential to effectively monitor Cr contamination in water systems and scientifically evaluate its evolution trend.A new method of in-situ tracer technique by Cr isotopic analysis for quantitatively estimating Cr-contamination and its regional evolution in natural waters as well as a case application are reported in this *** on documented literatures,an experimental procedure for chemical separation and purification of Cr in water samples and its analytical method for Cr isotopic measurement by thermal ionization mass spectrometry(TIMS) are *** samples collected around a chemical factory in Hubei Province were analyzed by this *** samples showδ53.r values ranging from-1.7‰to 7.3.and an elevating trend with an increasing in distance from the sampling site to pollution source.A functional correlation following Rayleigh fractionation law was established between sample'sδ53.r value and its extent of Cr *** study suggests that Cr isotopic analysis is an effective method to reveal the spatial distribution and its evolution trend of Cr contamination in the regional water *** is thus helpful to assessing the self-purifying ability of local water system according to Cr isotopic fractionation.

关键词：铬(VI) 水污染调查稳定同位素应用同位素分析供水系统演变趋势示踪技术

Ordovician-Silurian Boundary Extinction and Its Relationship to Iridium and carbon isotope Anomalies

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Acta Geologica Sinica(English Edition) 1990年第1期64卷 81-92页

作者： Wang Xiaofeng Chai Zhifang Yichang Institute of Geology and Minieral Resources, chinese academy of geological sciences, Yichang. Hubei Institute of High Energy, Academia Sinica, Beijing Liu Linqun Yichang Institute of Geology and Mineral Resources Chinese Academy of Geological Sciences Yichang Hubei China

The abundance distributions of more than 40 elements in the No. 502 Ordovician-Silurian (O/S) bounda-ry section at Fenxiang, Yichang have been studied by RNAA and INAA. The results show that in the bounda-ry bed, there is a distinctive Ir anomaly because the Ir concentration abruptly increases to 0.64 ppb.Furthermore, the Ir is positively correlated in abundance variation with some siderophile and sulphophile ele-ments. In the same bed of the O/S boundary section at Huanghuachang, Yichang, there is also a δ^(13.C excur-sion. These geochemical signs support the hypothesis that the terminal Ordovician mass extinction was proba-bly related to extraterrestrial event, and provide new evidence for defining the O/S boundary between theHirnantia-Kinnella and G. persculptus Zones.

关键词： Ordovician-Silurian Boundary Extinction and Its Relationship to Iridium and carbon isotope Anomalies Chen Wang

Sm-Nd isotopic geochronologyof the Yinachang Fe-Cu-REE deposit at Wuding, Yunnan Province and its genetic significance

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Science Bulletin 2005年第18期 124-130页

作者： YANG Yaomin1,2,3. TU Guanzhi1, HU Ruizhong1 & SHI Xuefa2 1. Institute of Geochemistry, chinese academy of sciences, Guiyang 550002,{3. 2. The Key laboratory of Marine Sedimentology and Environmental Geology, The First Institute of Oceanography, SOA, Qingdao 266061,{3. 3. Northwest geological Exploration Bureau, CNNC, Xi’an 710054,{3.

Sm-Nd isotope systematics of ores and fluorites places precise time constraints on REE mineralization of the Yinachang Fe-Cu-REE deposit in Yunnan Province which occur in the Proterozoic Kunyan group. The ore-related fluorites contain high abundant REE, and show a strong enrichment of LREE and a positive Eu anomaly, which is in marked contrast to post-ore fluorites that are HREE en-riched. The Sm-Nd isochron ages of the ores and fluorites are 153.±40 Ma and 1617±100 Ma, respectively, and calculated εNd(t) are ?4.6 and ?3.2. Accurate age determinations of the mineralization demonstrate that the REE mineralization took place during early Mesoproterozoic. Together with other geological evidence from the ore deposit, the primary REE-bearing ore-forming fluids are suggested to have been derived from the Enriched Mantle, and the Yinachang Fe-Cu-REE ore deposit is of volcanic exhalation- hydro-thermal sedimentary origin. This study also imply that the sudden large-scale REE mineralization in the Mesoprotero-zoic epoch may have been induced by alkaline-rich anoro-genic magmatism which occurred at marginal rifts of the continent in the Mesoproterozoic.

关键词： Kunyang rift Yinachang Fe-Cu-REE deposit fluorite Sm-Nd isotopic systematics Mesoproterozoic.

Event Stratigraphy, Biostratigraphy and Sequence Stratigraphy of Neoproterozoic in North china

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Journal of Earth Science 1999年第2期18卷 3-11页

作者： Qiao Xiufu Gao Linzhi Gao Mai Institute of Geology, chinese academy of geological sciences, Beijing 10003.

The aim of this study is to discuss the chronostratigraphy, catastrophic event stratigraphy, biostratigraphy and sequence stratigraphy of Neoproterozoic. In the eastern part of the North china, the Neoproterozoic consists of Qingbaikou System (1 000-800 Ma) and Sinian System (800-600 Ma). The Qingbaikou System is widely distributed over the whole area and the Sinian System only in the eastern and southern parts of the plate. In this paper, we discuss the age limit of the formations, and try to establish the Neoproterozoic chronostratigraphic frame, the ages of which are partly based on recently obtained carbonate whole rock Pb Pb isotope. Based on the event records of ancient earthquake, which are well developed in Sinian carbonates, “a vibrational liquefaction seismic sequence” in carbonate rocks is established. We propose a time correlation for the Sinian formation in eastern North china, on the bases of event records of earthquake in combination with biostratigraphy, and thus revise the traditional correlation scheme that has been used for nearly 3. years. Some biostratigraphic results were obtained in fossil microplants, megafossils and metazoans in North china. A large amount of big double layered and complex ornamented acritarchs are found in Qingbaikou and Sinian systems. On the basis of the correlation by earthquake events, the Huainan fauna is regarded as Late Sinian, probably between 700 Ma and 600 Ma. Altogether 16 depositional sequences are distinguished in the Neoproterozoic, with an average time interval of about 15-16 Ma.

关键词： catastrophic event stratigraphy biostratigraphy sequence stratigraphy Neoproterozoic North china.

Tectono-chronologic constraints on a Mesozoic slip and thrust belt in the eastern Jiaodong Peninsula

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Science china Earth sciences 2007年第1期50卷 25-32页

作者： ZHANG HongYuan1,2, HOU QuanLin3.& CAO DaiYong 4 1 Institute of Geology, chinese academy of geological sciences, Beijing 10003., china 2 State Key {3. of geological Processes and Mineral Resources, china University of Geosciences, Beijing 100083. china 3.Graduate School of china Acacemy of sciences, Beijing 10003., china 4 Key {3. of Coal Resources (CUMT), Ministry of Education, Beijing 100083. china Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China State Key laboratory of geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China Graduate School of china Acacemy of sciences Beijing 100039 China Key laboratory of Coal Resources (CUMT) Ministry of Education Beijing 100083 China

A major slip and thrust belt within the eastern Jiaodong Peninsula is located at the eastern terminal of the Qinling-Dabie-Sulu orogenic belt between the Sino-Korea Block and Yangtze Block. Although a lot of isotope chronologic data have been obtained regionally, little structural chronological research has been conducted in this region and this paper corrects that. Syn-deformational minerals were system-atically selected from samples of the NE-ENE trending transpressional shear zones and transpres-sional nappes and carefully analysed using 40Ar/3.Ar methods. Two tectonic events were defined with the first event resulting from early movement of transpressional nappes around 190 Ma ago. This ac-cords with the period of syn-orogenic sinistral slip of the Tan-Lu faults and clockwise shear in the Eastern Qinling-Tongbaishan part of the Qinling-Dabie-Sulu orogenic belt. The second event involved strikeslip thrust movement of deep shear zones between 13.Ma and 120Ma. This resulted from the onset of Mesozoic tectonic conversion in the eastern Jiaodong Peninsula. The sinistral strikeslip-thrusting in Jiaodong Peninsula and the extensional tectonism (toward ESE) in Liaodong Peninsula probably resulted in the clockwise rotation of Korea Peninsula in late Mesozoic.

关键词： the eastern Jiaodong Peninsula tectono-chronology 40Ar/3.Ar strikeslip and thrust belt.

Orogenic and Anorogenic Granitoids in the Altay Mountains of Xinjiang and Their Discrimination Criteria

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Acta Geologica Sinica(English Edition) 1989年第1期63卷 45-64页

作者： Zou Tianren Institute of Mineral Deposits, chinese academy of geological sciences, Beijing Chao Huizhi and Wu Baiqing Xinjiang Institute of Geology, Ministry of Metallurgical Industry Urumqi, Xinjiang Jiang Minxi 1Teliti and Yang Yueqing also participated in the field work. Those who participated in the laboratory study also include Yang Bingbin Duan Shangzhi Lü Qiaoling Li Longqi and Yu Shimei.

On the basis of field geological studies of the granotoids in the region, mineralogical, petrological, geochemical(including stable isotope geochemical) and isotopic geochronological investigations were carried out on selected representative granitic bodies of various types. The authors have concluded that, apart from the bodies of the orogenic granitoid series, there also exist intrusions of the anorogenic granitoid series in the region. The intrusives of the two series were formed not only in different ages and tectonic environments, but also were derived from different sources of materials. Moreover, they are associated with different mineralizations, belonging to different minerologenetic series(Cheng et al., 1983.. They show distinctly a series of discriminative criteria. The problems under discussion in the present paper are of important theoretical and practical significance in the studies of granites of the orogenic belt, particularly the studies of the genesis and related metallogeny of the granites of the region.

关键词： Orogenic and Anorogenic Granitoids in the Altay Mountains of Xinjiang and Their Discrimination Criteria

An early aged ophiolite in the Western Kunlun Mountain, northwestern Tibet plateau and its tectonic implications

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An early aged ophiolite in the Western Kunlun Mountain, nort...

An Experimental Calibration on the Sphalerite-Galena Sulfur isotope Geothermometer

2004年全国岩石学与地球动力学研讨会

作者： Xuchang XIAO Jun Wang Wenhua Ji Li Su 1. Institute of Geology, chinese academy of geological sciences (CAGS) 2. Regional geological Surveying Party of Shanxi Provence 3. Xi''An Institute of Geology and Mineral Resources

＜正＞ The early aged ophiolites have attracted the studying from many geologists in recent decades （Colombo C. G. et al, 2001, Scarrow J. H. et al., Timothy M. Kusky et al., 2001.....）, because the early aged ophiolites can provide the information about the ancient oceanic processes relevant to the evolution of the plate tectonics in the early period of the earth, and also concem such problems as whether there existed a "Protero-Tethys" and the break-up and convergence of the Rodinia Supercontinent in the NW Tibet plateau. This paper reveals a definite complete ophiolite, the "Kudi- ophiolite" of late-Proterozoic-early Paleozoic, in the Westem Kunlun Mtns, NW. Tibet plateau, and reports the recent isotopic ages of 510±4Ma. And 502±13.a （U-Pb ratio in zircon） for the middle and upper portions of the mafic cumulates of the Kudi-ophiolite, operated at the most powerful dating tool, the shrimp-Ⅱ. The geochemical and geochronological data integrating with the geological setting suggest that the Kudi-ophiolite might have formed in an Archipelago not in a vast oceanic basin, the so-called Protero-Tethys, and was tectonically emplaced during the early Paleozoic in the NW. Tibet plateau.

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Acta Geologica Sinica(English Edition) 2003年第4期77卷 519-521页

作者： DING Tiping, ZHANG Chengxin, WAN Defang, LIU Zhijian and ZHANG Guilan Institute of Mineral Resources, chinese academy of geological sciences, 26 Baiwanzhuang Rd.,Beijing 10003. chinese Acad Geol Sci Inst Mineral Resources Beijing 100037 Peoples R China

A new experimental calibration was undertaken in this study to get a more reliable sphalerite-galena sulfur isotope geothermometer. The experimental conditions selected in study were very similar to those of natural hydrothermal solution. The high-precision SF6 method was used in sulfur isotope analyses. The obtained calibration curve for sulfur isotope fractionation between sphalerite and galena can be expressed with the equation 10001nαSp-Gn= 0.74×106T-2+0.08.

关键词： sulfur isotopes isotope geothermometer SF6 method sphalerite galena