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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.{3. 2. Tarim Oilfield Company Exploration & Development Research {2., Ku’erle 84.000,{3. 3. {2. of Mineral Resources, Chinese Academy of geological sciences, beijing 10003.,{3.) 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 δ3.Si 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..{3.2..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.

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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.,{3. 2. Laboratory for Earth Material Cycling, School of Earth and Space {2., University of Science and Technology of{3., Hefei 2.002.,{3. 3. institute of Mineral Resource, Chinese Academy of geological {2., beijing 10003.,{3. National Research Center of Geoanalysis beijing 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 {2. {3.{4.

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 0.2.9 ± 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 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.

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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 {2. {3.,{4., 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.

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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 {2. {3., beijing 10003.,{4. National Center of Rock and Mineral Analysis, Chinese Academy of {2. {3., beijing 10003.,{4. Resource Assessment Center of Yunnan, Kunming 650011,{4. institute of {12. and Geophysics, Chinese Academy of {3., beijing 100101,{4. Chinese Academy of {2. {3., beijing 10003.,{4. 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 3..9±1.1 Ma for the Machangqing deposit and 3.0}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 (3..4.Ma, 3..9 Ma, 3..{3.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.

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Control of atmospheric CO_2.concentrations by 2.50: A calculation on the emission rights of different countries

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Science china Earth sciences 2009年第10期52卷 1447-1469页

作者： DING ZhongLi1, DUAN XiaoNan2. GE QuanSheng3.& ZHANG ZhiQiang4.1 institute of {2. and Geophysics, Chinese Academy of sciences, beijing 10002.,{4. 2.The General Office of Chinese Academy of sciences, beijing 100864.{4. 3.institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, beijing 100101,{4. 4.The Lanzhou Branch of the National Science Library, the Scientific Information Center for Resources and Environment, Lanzhou 73.000,{4. institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China The General Office of Chinese Academy of sciences Beijing 100864 China institute of Geographic sciences and Natural Resources Research Chinese Academy

This paper is to provide quantitative data on some critical issues in anticipation of the forthcoming international negotiations in Denmark on the control of atmospheric CO2.concentrations. Instead of letting only a small number of countries dominate a few controversial dialogues about emissions reductions, a comprehensive global system must be established based on emissions allowances for different countries, to realize the long-term goal of controlling global atmospheric CO2.concentrations. That a system rooted in "cumulative emissions per capita," the best conception of the "common but differentiated responsibilities" principle affirmed by the Kyoto Protocol according to fundamental standards of fairness and justice, was demonstrated. Based on calculations of various countries' cumulative emissions per capita, estimates of their cumulative emissions from 1900 to 2.05, and their annual emissions allowances into the future (2.06―2.50), a 4.0 ppmv atmospheric CO2.concentration target was set. According to the following four objective indicators―total emissions allowance from 1900 to 2.50, actual emissions from 1900 to 2.05, emissions levels in 2.05, and the average growth rate of emissions from 1996 to 2.05―all countries and regions whose population was more than 3.0000 in 2.05 were divided into four main groups: countries with emissions deficits, countries and regions needing to reduce their gross emissions, countries and regions needing to reduce their emissions growth rates, and countries that can maintain the current emissions growth rates. Based on this proposal, most G8 countries by 2.05 had already expended their 2.50 emissions allowances. The accu-mulated financial value based on emissions has reached more than 5.5 trillion US dollars (2. dollars per ton of CO2.. Even if these countries could achieve their ambitious emissions reduction targets in the future, their per capita emissions from 2.06 to 2.50 would still be much higher than those of developing coun

关键词： international negotiations on climate change cumulative emissions per capita emission allowance

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Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan,Northwest china:Evidence from sandstone detrital and geochemical records

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Science china Earth sciences 2005年第9期48卷 1387-1402页

作者： LI Zhong1, GUO Hong2. WANG Daoxuan3.& LIN Wei1 1. institute of geology and Geophysics, Chinese Academy of {2., beijing 10002.,{4. 2. Tarim Oilfield Branch, CNPC, Korla 84.000,{4. 3. Hefei University of Industry, Tunxilu 193. Hefei 2.0009,{4. 1. institute of geology and Geophysics Chinese Academy of Sciences 100029 Beijing Chin 2. Tarim Oilfield Branch CNPC 841000 Korla China 3. Hefei University of Industry Tunxilu 193 230009 Hefei Chin

Similar to compositional evolution of sandstone modes and detrital heavy minerals from different profiles in the Kuqa Depression, Northwest china, major element analysis of whole sandstones from the same profiles shows four discontinuous depositional interfaces or periods, respectively corresponding to Lower Triassic\Middle Triassic, Upper Jurassic\Lower Cretaceous, Lower Cretaceous\Paleogene and Miocene\Pliocene, and indicates five-phase evolution during Mesozoic-Cenozoic: (1) From the first to fifth phase, a depositional suite changes from maroon and coarse clastic, through grey-dark grey and fine, red and coarse, red-mottled, interlayered by gypsum, to brown and coarse clastic assemblages, accompanying detrital component evolution in unstable-stable-unstable-very unstable-very unstable assem- blages. It is indicated that carbonate and complex detritus gradually dominate in sandstones in post-Late Jurassic, with rapid reduction of compositional maturity. (2. For major element geo- chemical parameters of whole sandstones, CaO and Fe2.O * 3.MgO contents show a change sequence in high-low-high-higher-highest values, with rapid increasing in post-Late Jurassic. (3. Contra some aggregative indicators for weathering indexes of sandstone detrital component, Al2.3.(CaO+Na2.) and ln(Q/(L+CE)), show a change sequence in low-high-low-lower-lowest ratios, with rapid decreasing in post-Late Jurassic. It is found that sandstone samples of the first, second and later three phases may be distinguished from the A-CN-K and A-CNK-FM diagrams respectively. Therefore, in the Kuqa Depression-Tianshan, the most important discontinuous depositional interface recording paleotectonic and paleoclimatic transition occurred in Early Triassic\Middle Triassic and Late Jurassic\Early Cretaceous, respectively, and, however, tec- tonic differentiations of basin-range system finally result in distinct depositional systems but similar detrital weathering indexes across the Lower Cretaceous\Paleogene

关键词： Tianshan, Kuqa Depression, basin-range, depositional record, tectonic transition, Mesozoic-Cenozoic.

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Gas formation mechanism of marine carbonate source rocks in china

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Science china Earth sciences 2005年第4期48卷 441-453页

作者： ZHAO Wenzhi1, WANG Zhaoyun1, HE Haiqing2. ZHANG Mingjie3. WANG Hongjun1, WANG Yunpeng4.& QIN Yong5 1. Research institute of Petroleum Exploration & Development, Petro{2., beijing 100083. china 2. Petro{2. Exploration & Production, beijing 100011, china 3. Department of geology, Lanzhou University, Lanzhou 73.000, china 4. Guangzhou Geochemical institute, Chinese Academy of {12., Guangzhou 51064., china 5. china University of Mining and Technology, Xuzhou 2.1000, china 1. Research institute of Petroleum Exploration & Development 100083 PetroChinaBeijin China 2. Petrochina Exploration & Production 100011 Beijing China 3. Department of geology Lanzhou University 730000 Lanzhou China 4. Guangzhou Geochemical institute Chinese Academy of Sciences 510640 Guangzhou China 5. china University of Mining and Technology 221000 Xuzhou China

By breaking through the conventional ideology on the study of gas-formation mechanism of source rocks which focused on merely the characteristics of source rocks them- selves, and based on the development and distribution characteristics of marine carbonate source rocks in the medium-to-bottom parts of the Chinese superimposed sedimentary basins as well as various processes in the course of gas generation and reservoir forming, the complex hydrocarbon-generating model of carbonates is established. Such a model concerns not only the “three-stage” gas formation characteristics of carbonates, but also the gas generation process due to a thermal cracking of oil and the re-generation process of gas from heated secondary organic matters during the gas-generation and reservoir-forming course. The high-quality hy- drocarbon generating matter of marine carbonate source rocks determined a high gas-oil ratio and tended to form paleo-oil-reservoirs, representing an enrichment process of organic matters. The thermal cracking of oil in palaeo-oil-reservoirs is an important means for the effective forma- tion of gas reservoirs. The secondary organic matters in carbonate reservoirs may regenerate gas after a secondary deep burial, thus becoming an effective gas source.

关键词： carbonate, three-stage hydrocarbon generation, inhibitive effect of maturity, oil-cracking gas, second-ary asphalt gas.

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Paleotemperature changes over the past 3.00 years in eastern beijing, china: A reconstraction based on Mg/Sr records in a stalagmite

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Chinese Science Bulletin 2003年第4期48卷 395-400页

作者： MA Zhibang1, LI Hongchun2. XIA Ming1, KU Tehlung2. PENG Zicheng3. CHEN Yushu4.& ZHANG Zhaofeng3.1. {3. of {2. and Geophysics, Chinese Academy of sciences, beijing 10002.,{4. 2. Department of Earth sciences, University of Southern California, Los Angeles, CA90089-074., USA 3. Department of Earth and Space Science, University of Science and Technology of{4., Hefei 2.002.,{4. 4. beijing Foshan Tourist Service Centre, beijing 1012.1,{4. institute of geology and Geophysics. Chinese Academy of {2. Beijing 100029 China

The Mg/Sr ratio in a stalagmite, which is di-rectly proportional to DMg/Ca, the solid-liquid distribution coefficient of Mg, is proposed as a geochemical thermometer to estimate paleotemperature changes. The paleotempera-ture change in eastern beijing over the past 3.00 years has been reconstructed by using this thermometer in the stalag-mite ZFFS-1 from Jingdong Cave. The records can be di-vided into two periods: 3.00—2.00 aBP, cool and wet, the air temperature averaging 9.8℃; and 2.00 aBP—present, hot and dry, the air temperature being 1℃ higher than the mean value (11.7℃) of the past 3.00 years. During 500—2.0 aBP, the air temperature was about 1.2. lower than that of the present, corresponding to the Little Ice Age in Europe. Like d 18O and d 13., Mg/Sr (or DMg/Ca) reflects an obviously warming trend of the past 2.0 years. These results are sup-ported by historic records.

关键词：北京京东溶洞石笋 Mg/Sr记录古气温测年 3.00年

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Seismic multi-arch structures in East china

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Science china Earth sciences 2006年第2期49卷 133-146页

作者： YANG Wencai1 & CHEN Zhide2.1.institute of geology, Chinese Academy of {2. sciences,{4., china 2.Daqing institute of Petroleum Exploration and Production, Daqing 163.12. china 1. institute of geology Chinese Academy of Geological Sciences Beijing 100037 China 2. Daqing institute of Petroleum Exploration and Production Daqing 163712 China

In previous papers (Wencai, 2.02. 2.03., the author has analyzed the deep seismic reflection profiles along some of the Mesozoic plutons in East{3., and has pointed out that the crustal structures around these intrusions usually correlate with a special seismic fabric called the seismic multi-arch structure. This paper will continue to show main characteristics of the seismic multi-arch structures and discuss their relationship with mantle-origin magmatism and the lithospheric thinning process. Calibration of seismic reflectors in Chinese continental drilling sites shows that small-scale arch-like reflectors can be generated by fractured eclogites or other plutons, they do not belong to the multi-arch structure specially discussed in the paper. The multi-arch structure is char-acterized by several arch-like reflectors distributed in both the upper and lower crust with granitoid plutons or stocks exposed on the surface, which do not have obvious negative Europium anomalies. Based on the distribution pattern of arch reflectors, the multi-arch magmatic structures can be divided into three main types, namely the simple vertical combination type, the spread arch magmatic struc-ture and the arch-bouquet structure. All of them correlate to mantle-origin magmatism, but occur in different places. The spread arch magmatic structures occur within a Mesozoic/Cenozoic rift zone with very thin and hot lithosphere. The vertical combination type of the multi-arch structures occurred near the rift zones where lithosphere was thin and hot. The arch-bouquet magmatic structures occur far from the rift zones where the lithosphere is not hot. The continental rifting acted as the late episode of the lithospheric thinning process seeing that the rift zones usually coincide with the thinnest parts of the lithosphere in East{3.. In different locations within the lithospheric thinning areas, mantle-origin magmatic activities have different characteristics, which might generate different

关键词： deep seismic reflection, multi-arch structure, eclogite bodies, mantle-origin magmatism, East china.

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Vermiform trace fossils from the Precambrian Ruyang Group, western Henan

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Chinese Science Bulletin 1997年第3期42卷 251-254页

作者： HU Jianmin, MENG Qingren and LI Wenhou1 Xi’ an College of geology, Xi’an 710054.{2. 2. institute of Geophysics, Chinese Academy of sciences, {4. 100101,{2. 3.Department of geology, Northwest University, Xi’an 710069,{2. Xi’an College of geology Xi’an China institute of Geophysics Chinese Academy of Sciences Beijing China Department of geology Northwest University Xi’an China

THE origin and evolution of Precambrian lives has been a long-standing controversial problem. It is now generally accepted by most paleontologists that the origin of metazoa can be traced back to more than 1000 Ma, because the Ediacara and latest pre-Ediacara fauna, such as the Huainan fauna, are featured by their diversification of forms, complicated structures

关键词： Precambrian trace fossil Ruyang Group.

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