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Isotopic compositions of small shelly fossil Anabarites from Lower Cambrian in Yangtze Platform of South China: Implications for palaeocean temperature

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Progress in Natural Science:Materials International 2007年第10期17卷 1185-1191页

作者： Chen Yongquan1,2. Jiang Shaoyong1, Ling Hongfei1, Yang Jinghong1 and Wan Defan3(1. State Key Laboatory for Mineral Deposits research and center for Marine Geochemistry research, Department of Earth Sciences, Nanjing University, Nanjing 2.0093, China 2. Tarim Oilfield Company Exploration & development research Institute, Ku’erle 841000, China 3. Institute of Mineral Resources, Chinese Academy of geological Sciences, beijing 100037, China) State Key Laboatory for Mineral Deposits research and center for Marine Geochemistry research Department of Earth Sciences Nanjing University Nanjing 210093 China arim Oilfield Company Exploration & development research Institute Ku’erle 841000 China Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing 100037 China

Anabarites belong to small shelly fossils (SSF), which occur widely in the Lower Cambrian strata of Yangtze Platform in South China. They are phosphate shell in composition and represent the earliest stage of the Cambrian bioradiation of Bilateria, the so-called "Cambrian Explosion". In this study, we attempted to separate Anabarites fossils from Lower Cambrian dolostones, and we obtained samples of both the fossils (SSF) and the granular phosphates (GP). Isotopic analyses were performed on samples of SSF, GP, and matrix dolostone (DH-2.). The results showed that the δ30Si values of the quartz filling in fossils celoms, and the siliceous materials in granular phosphates are -0.6‰ and -0.7‰, which is different from normal sedimentary siliceous rocks from the Lower Cambrian strata (0—0.7‰) as reported by Li et al., but is consistent with the data for siliceous rocks and cherts of submarine hydrothermal origin. It is likely that a later hydrothermal replacement could have taken place in the SSF-bearing sedimentary rocks. The oxygen isotope values of the phosphate of SSF and GP are 16.8‰ and 17.0‰, respectively. These are significantly higher than the Neoproterozoic phosphate ores (10.9‰—13.9‰) as reported by Ling et al., hence, late diagenesis and hydrothermal replacement may not have caused a significant change in the oxygen isotope compositions of the small shelly fossils, and the calculated temperatures (2..4—2..3℃) for palaeo-seawater using a SSF phosphate oxygen isotope thermometer are therefore considered here as the upper limit of seawater temperature in the Early Cambrian ocean of the Yangtze Platform.

关键词： Anabarites oxygen isotope silicon isotope paleo-temperature.

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,{2., China 2. Laboratory for Earth Material Cycling, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 2.002., China 3. Institute of Mineral Resource, Chinese Academy of geological Sciences,{2., China National research center of Geoanalysis {2. China Laboratory for Earth Material Cycling School of Earth and Space Sciences University of Science and Technology of China Hefei China Institute of Mineral Resource Chinese Academy of geological Sciences beijing China

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 833 ± 35 Ma, initial 187Os/188Os ratio of 0.2.9 ± 0.018 (MSWD = 1.7) and γOs = 130 ± 15 is obtained. The Re-Os age obtained agrees, within analytical uncertainties, with previous SHRIMP zircon U-Pb age of 82. ± 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.

A preliminary study on vegetation-erosion dynamics and its applications

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Science China Earth Sciences 2005年第5期48卷 689-700页

作者： WANG Zhaoyin 1,2., WANG Guangqian 1 , LI Changzhi 1 & WANG Feixin 1 1. Department of Hydraulic Engineering, Tsinghua University, beijing 100084, China 2. International research and Training {2. on Erosion and Sedimentation, beijing 100084, China 1. Department of Hydraulic Engineering Tsinghua University 100084 Beijing China 2. International research and Training center on Erosion and Sedimentation 100084 Beijing China

Vegetation-erosion dynamics is a new interdisciplinary science, studying the laws of evolution of watershed vegetation under the action of various ecological stresses. Introducing a qualitative expression of ecological stresses in this paper, the present authors establish the cou- pled differential equations for the vegetation-erosion process and derive a theoretical solution. The model is applied to the Anjiagou watershed on the Loess Pateau and the Xiaojiang water- shed and its sub-watersheds on the Yunnan Plateau. The calculated results agree well with the vegetation development processes. Abstracted from the differential equations the so-called vegetation-erosion chart is worked out, with which we can predict the development trend of vegetation under no human stresses. It is demonstrated that the erosion control is important for vegetation development and reforestation must be a long-term strategy. On the Yunnan Plateau with relatively high precipitation and temperature, vegetation can be greatly improved if erosion is controlled. On the dry and cold Loess Pateau suffering from high rate of soil erosion, however, vegetation can effectively control erosion but erosion reduction exhibits low effectiveness on vegetation development. Vegetation in the area is not stable and management is always needed to maintain the vegetation.

关键词： vegetation-erosion dynamics, human activities, coupled differential equations, erosion control, vigor ofvegetation.

Discovery of Cu-Zn,Cu-Sn intermetallic minerals and its significance for genesis of the Mianning-Dechang REE Metallogenic Belt,Sichuan Province,China

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Science China Earth Sciences 2006年第6期49卷 597-603页

作者： XIE Yuling1, HOU Zengqian2. XU Jiuhua1, YUAN Zhongxin2. BAI Ge2.& LI Xiaoyu3 1. Civil and Environmental Engineering School, University of Science and Technology beijing, beijing 100083, China 2. Institute of Geology, Chinese Academy of {2. Sciences, beijing 100037, China 3. The 109th {2. Team, Sichuan Bureau of Mineral Exploration, Chengdu 610100, China 1. Civil and Environmental Engineering School University of Science and Technology Beijing Beijing 100083 China 2. Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China 3. The 109th geological Team Sichuan Bureau of Mineral Exploration Chengdu 610100 China

Mianning-Dechang Himalayan REE Metallogenetic Belt in Sichuan Province lies along the western margin of the Yangtze Craton. We have conducted detailed mineralogical studies on ore minerals collected from Maoniuping and Dalucao, the two largest deposits in the belt. With optical microscope, SEM/EDS, and EPMA, three rare intermetallic minerals, i.e., zinccopperite (Cu2.n), Sn- bearing native copper, and Cu-bearing jupiter were found to occur in the main ore along with barite, fluorite, apatite, sulfide and bastnaesite. Since the conditions under which zinccopperite and Sn- bearing native copper formed are quite unique, finding of these minerals, for the first time in domestic REE deposits, has significant implications for the genesis of the ore deposits in which they occur. In comparison with Cu-Zn intermetallic minerals in other occurrences, we propose that the formation of this REE metallogenetic belt is associated with fast upwelling of the Himalayan magma from deep source.

关键词： Mianning-Dechang REE metallogenetic belt, Cu-bearing intermetallic minerals, EPMA, genesis significance, deep source magmatic activity.

Lithosphere types in North China:Evidence from geology and geophysics

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Science China Earth Sciences 2005年第11期48卷 1809-1827页

作者： QIU Ruizhao1,2. DENG Jinfu3, ZHOU Su3, LI Jinfa4, XIAO Qinghui1,5, WU Zongxu6 & LIU Cui3 1. Institute of Geology, Chinese Academy of geological Sciences, beijing 100037, China {2., China geological survey, beijing 100037, China 3. China University of Geosciences, beijing 100083, China 4. China University of Geosciences, Wuhan 430074, China 5. Information center of Ministry of Land and Resources, beijing 100812. China 6. Institute of Geology, State Seismological Bureau, beijing 10002., China 1. Institute of Geology Chinese Academy of Geological Sciences 100037 Beijing China 2. development and research center China Geological Survey 100037 Beijing China 3. China University of Geosciences 100083 Beijing China 4. China University of Geosciences 430074 Wuhan China 5. Information center of Ministry of Land and Resources 100812 Beijing China 6. Institute of Geology State Seismological Bureau 100029 Beijing China

On the basis of the characteristics of geology and geophysics in North China, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method (based on the information from Precambrian rock assemblages, igneous activities, deep-seated enclaves, etc.) and the relationship between seismic velocity and rock compositions, the crust-mantle petrological and chemical structure models can be set up. researching results indicate that the geology and geophysics of North China platform bears the similar characteristics in comparison with those of the global typical cratons. The Eerduosi(Ordos) block located in the west of the North China Platform is a remnant of cratonic lithosphere after the North China platform had undergone “activation” in Mesozoic and “reconstruction” in Cenozoic times. The continental crust consists mainly of TTG rock assemblage while the subcontinental lithosphere mantle mainly consists of strongly depleted harzburgite. The craton was finally formed in late Archaean and early Proterozoic, and has been kept in stability up to present; its crustal-mantle petrological structures of lithosphere can be set up as a reference for the study of North China craton and even Sino-Korean craton. In the Mesozoic period, the middle and east areas of North China platform were activated in the Yanshanian orogenic process, the continental crust was reformed by material and heat-transfer of convective mantle and the original crustal TTG component was reconstructed to be granitic crust, and the subcontinental lithosphere man- tle was replaced by the Yanshanian harzburgite-lherzolite. The Yanshan-Taihang Mountains were the remnants of orogenic lithosphere after the rifting in eastern North China in Cenozoic. The present thickness of continental crust and lithosphere in the Yanshan-Taihang Mountains is not equal to their thickness during the Yanshanian orogenic movement because they had undergone the

关键词： lithospheric types,evidence of geology and geophysics,crust-mantle petrological structure,deep process

SHRIMP zircon U-Pb age and Nd isotopic study on the Nyainqêntanglha Group in Tibet

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Science China Earth Sciences 2005年第9期48卷 1377-1386页

作者： HU Daogong1, WU Zhenhan1, JIANG Wan1, SHI Yuruo2. YE Peisheng1 & LIU Qisheng1 1. Institute of Geomechanics, Chinese Academy of geological Sciences, beijing 100081, China 2. Institute of Geology, Chinese Academy of geological Sciences, beijing SHRIMP Centre, beijing 100037, China 1. Institute of Geomechanics Chinese Academy of Geological Sciences 100081 Beijing China 2. Institute of Geology Chinese Academy of Geological Sciences Beijing SHRIMP Centre 100037 Beijing China

The Nyainqêntanglha Group is traditionally viewed as the oldest metamorphic basement in the Lhasa block, but its formation age and tectonic setting remain debate. Zircons extracted from the metamorphic sequence of volcanics and intrusions of the Nyainqêntanglha Group, 10 km west of Nam Co in northern Lhasa block, have been investigated by cathodolu- minescence (CL), backscattered (BSE) and dated by ion microprobe (SHRIMP). We conclude that the U-Pb age of 787±9 Ma of zircons from the trondhjemite imposes a constraint on maxi- mum protolith age, and minimum formation age of the Nyainqêntanglha Group is constrained by U-Pb age of 748±8 Ma of zircons from the granite. The formation age of the Nyainqêntanglha Group is consistent with sedimentary age of Greater Himalayan rocks, showing that they devel- oped coevally in an arc-basin tectonic setting of Neoproterozoic active continental margin along the northern margin of the India shield. The inherited zircons from the tholetiite and granite give older 2.7Pb/2.6Pb ages from 947 to 1766 Ma. The positive εNd( t ) value indicates that the mafic rocks were derived from the depleted mantle, but contaminated by the older continental crustal material. Integrated Nd model age and U-Pb age data provide excellent evidence for the exis- tence of Mesoproterozoic basement in the Lhasa block during Neoproterozoic time.

关键词： Nyainqêntanglha Group, SHRIMP dating, Nd isotope, Neoproterozoic, Tibet.

Integrative inversion of land surface component temperature

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Science China Earth Sciences 2005年第11期48卷 2011-2019页

作者： FAN Wenjie1 & XU Xiru1,2.1. Institute of Remote Sensing and Geographical Information System, Peking University, beijing 100871, China 2. center of Remote Sensing and GIS of beijing Normal University, beijing 100875, China 1. Institute of Remote Sensing and Geographical Information System Peking University 100871 Beijing China 2. center of Remote Sensing and GIS of beijing Normal University 100875 Beijing China

In this paper, the row winter wheat was selected as the example to study the com-ponent temperature inversion method of land surface target in detail. The result showed that the structural pattern of row crop can affect the inversion precision of component temperature evi-dently. Choosing appropriate structural pattern of row crop can improve the inversion precision significantly. The iterative method combining inverse matrix was a stable method that was fit for inversing component temperature of land surface target. The result of simulation and field ex-periment showed that the integrative method could remarkably improve the inversion accuracy of the lighted soil surface temperature and the top layer canopy temperature, and enhance inver-sion stability of components temperature. Just two parameters were sufficient for accurate at-mospheric correction of multi-angle and multi-spectral thermal infrared data: atmospheric trans-mittance and the atmospheric upwelling radiance. If the atmospheric parameters and component temperature can be inversed synchronously, the really and truly accurate atmospheric correction can be achieved. The validation using ATSRII data showed that the method was useful.

关键词： components temperature, inverse pattern, atmospheric correction

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 1. geological surveying Institute of Hainan 570206 Haikou China 2. Institute of Geomechanics Chinese Academy of Geological Sciences 100081 Beijing China 3. beijing center of SHRIMP 100037 Beijing China 4. Institute of Geology Chinese Academy of Geological Sciences 100037 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 {2. 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.

THz spectrum of reduced glutathione

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Science China(Physics,Mechanics & Astronomy) 2005年第5期48卷 585-592页

作者： WANG Weining1, YAN Haitao1, YUE Weiwei1, ZHAO Guozhong1, ZHANG Cunlin1, LIU Haibo2.& ZHANG Xicheng2.1. Department of Physics, Capital Normal University, beijing 100037, China 2. center for Terahertz {2., Rensselaer Polytechnic Institute, Tory, NY, USA 1. Department of Physics Capital Normal Univesity 100037 Beijing China 2. center for Terahertz research Rensselaer Polytechnic Institute Tory NY USA

The optical characteristics of reduced glutathione molecules between 0.2.THz and 2.4 THz have been investigated by THz time-domain spectroscopy (THz-TDS). The absorption characteristics and optical parameters of the reduced glutathione purged with Nitrogen at room temperature were obtained experimentally. The measured results were fitted well with the theoretical results computed by using Density Functional Theory (DFT) in far-infrared range. Also the conformation of the reduced glutathione molecule was simulated by Gaussian 03. This work has demonstrated significantly that THz-TDS spectroscopy can further be used to study other biological molecules in biological and biomedical engineering.

关键词： THz time domain spectroscopy, reduced glutathione, absorption spectrum, biological engineering.