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A Study of Mesoproterozoic Iron Cosmic Micro-spherules from 1.8 Ga and 1.6 Ga Old Strata in the Ming Tombs District,Beijing

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Acta Geologica Sinica(English Edition) 2007年第4期81卷 649-657页

作者： SONG Tianrui HE Zhengjun wan yusheng and liu yanxue institute of geology,chinese {2. of {3. Sciences,Beijing 10003. chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

Numerous iron cosmic micro-spherules have been discovered from Mesoproterozoic strata including the Changzhougou Formation （1.8 Ga） and the Dahongyu Formation （1.6 Ga） of the Ming Tombs district, Beijing. There are 1 to 3. grains of cosmic spherules per 2.kg of a sandstone sample taken from the bottom of a coarse sandstone bed of the Changzhougou Formation and 56 grains per 3.69 kg of a rock sample from silicified carbonate rocks of the Dahongyu Formation. The surface textures of cosmic spherules analyzed by means of the secondary electron imagery are identical with those reported from references either domestic or abroad. So far the geo-ages of 1.8 Ga and 1.6 Ga of cosmic spherules from the Changzhougou and Dahongyu formations might be older than those reported in the world. Table 1 gives the electron probe analysis data of cosmic spherules for 3. spherule grains and 44 testing points as follows （%）： FeO, 80-95; Cr2.3. 0-9.56; NiO, 0-0.78; CoO, 0-0.46; indicating that the Cr2.3.content is higher and FeO content lower in the Changzhougou Formation than in the Dahongyu Formation. The he{3.m isotopic data of cosmic spherules as well as their host rocks vary greatly between the Changzhougou and the Dahongyu formations as shown in Table 2. The data of cosmic spherules of the Changzhougou Formation vs the Dahongyu Formation are 57.5/1.2. in ^3.e/^4He （10^-8）; and 55.54/809.60 in ^4He （10^-6cm^3.TP/g）; those of coarse sandstone of the Changzhougou Formation vs silicified carbonate of the Dahongyu Formation are 3.3./2.59 in ^3.e/^4He （10^-8） and 4.56/2.3. in ^3.e （10^-6cm^3.TP/g）. The ratio of analytic data of he{3.m isotopes are different for cosmic spherules and their host rocks; for example, the ^3.e/^4He （10^-8） values are 16.96 and 0.48, and the ^4He （10^-6 cm^3.TP/g） are 12.18 and 3.5.98 for the Changzhougou and Dahongyu formations respectively. It was reported that the world＇s oldest micrometeorites had been found in the Meso-Proterozoic Satakunta Formation, Finland

关键词： Proterozoic cosmic spherule helium isotopes extraterrestrial material carbonaceous chondrite

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Ages and Compositions of the Precambrian High-grade Basement of the Qilian Terrane and Its Adjacent Areas

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Acta Geologica Sinica(English Edition) 2001年第4期75卷 375-384页

作者： wan yusheng, XU Zhiqin, YANG Jingsui and ZHANG Jianxin {2. of {3., {3. academy of geological Sciences, Beijing 10003. chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

Based on geological, chronological, geochemical and Nd isotopic studies of the high-grade basement of the Qilian terrane, the authors have drawn the following main conclusions: (1) the high-grade basement of the Qilian terrane consists mainly of meta-argillo-arenaceous rocks and granites and its bulk part was formed in the period of 0.8–1.0 Ga (the Jinningian period); (2. most of the meta-argillo-arenaceous rocks and granitic rocks have strong negative Eu and Ba anomalies (Eu/Eu*= 0.47–0.71 and Ba/Ba*=0.16–0.64), with fDM and ENd (1.0 Ga) ranging from 1.87 to 2.2. Ga and from ?8.54 to ?4.06 respectively, showing relatively high maturity; and (3. the Jinningian granitic rocks are a typical product of continent-continent collision, being probably related to the formation of the supercontinent Rodinia. These studies, combined with the study of high-grade basement rocks near the Qilian terrane, suggest that before the Jinningian period, the Qilian-Qaidam northern-margin terrane and Dunhuang-Alxa terrane were separated from each other, belonging to different plate systems of the North China craton and Yangtze platform respectively. The Qilian orogenic belt was the same as or similar to the Qiling orogenic belt in terms of the geological evolution history at least before the Jinningian period.

关键词： Qilian terrane chronology Nd isotope geochemistry Precambrian basement

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SHRIMP ages of detrital zircons from the Changcheng System in the Ming Tombs area,Beijing:Constraints on the protolith nature and maximum depositional age of the Mesoproterozoic cover of the North China Craton

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chinese Science Bulletin 2003年第22期48卷 2500-2506页

作者： wan yusheng1,2. ZHANG Qiaoda1 & SONG Tianrui1 1. {2. of geology, {3. academy of geological Sciences, Beijing 10003., China 2. Beijing SHRIMP Laboratory, Beijing 10003., China Correspondence should be addressed to wan yusheng (e-mail: wanyusheng@***) institute of geology Chinese Academy of Geological Sciences Beijing China Beijing SHRIMP Laboratory Beijing China

The Mesoproterozoic Changcheng System is widely distributed in the North China Craton. Determining its time of deposition and sources is important to understand the Precambrian crustal evolution of the North China Craton. This paper suggests age distribution patterns for detrital zircons from clastic sediments of the Changcheng System in the Ming Tombs area, Beijing. Samples of feldspar-bearing sandstone (CHc-2. and pure sandstone (CHc-9) were collected from the Changzhougou Formation, which constitutes the basal part of the Changcheng System. Detrital zircons show an age range from 2.3. to 2.60 Ga. However, sample CHc-9 in the upper Changzhougou Formation also contains some zircons with ages of 1.9-1.8 Ga and 2.3.2.1 Ga. The age patterns lead to the following conclusions: (1) Most of the detrital material came from a source area composed predominantly of ~2.5 Ga continental crust of the North China Craton; (2. 1.9-1.8 Ga reflects the age record of Palaeoproterozoic continent-continent collisional event in the North China Craton; and (3. the oldest age for deposition of the Changcheng System is 1.8 Ga.

关键词：锆石原岩中国北部地区地壳演变

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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. {2. of Geomechanics, chinese academy of {3. Sciences, Beijing 100081, China 2. {2. of geology, chinese academy of {3. Sciences, Beijing SHRIMP Centre, Beijing 10003., China institute of Geomechanics Chinese Academy of Geological Sciences Beijing China institute of geology Chinese Academy of Geological Sciences Beijing SHRIMP Centre 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.

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Storm Deposits of the Sinian Zhangqu Formation in Northern Anhui——An Upward Shallowing Carbonate Sequence

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Acta Geologica Sinica(English Edition) 1990年第2期64卷 129-145,234-235页

作者： Qiao Xiufu Xing yusheng Gao Linzhi Yin Chongyu Yue Zhao liu Guizhi {2. of {3., {3. academy of geological Sciences, Beijing Jia Zhongpeng Gao Linzhi chinese academy of {2. Sciences Beijing

This paper studies. for the first time, the storm deposits of a carbonate sequence in the Sinian ZhangquFormation in northern Anhui. In the formation. a great number of calcareous trider sponge spicules were dis-covered in a distal storm turbidity sequence, which have provided further evidence for the correlation of theSinian Systems in North and South China from a view point of palaeontology.

关键词： Zhang Storm Deposits of the Sinian Zhangqu Formation in Northern Anhui An Upward Shallowing Carbonate Sequence

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The influence of silica on reaction rates and molecular hydrogen(H_(2.)generation during olivine hydrothermal alteration

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Science China Earth Sciences 2024年第1期67卷 222-233页

作者： Ruifang HUANG Weidong SUN Xing DING yusheng ZHAO Yibing LI Xiuqi SHANG CAS Key Laboratory of Ocean and Marginal Sea geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China SUSTech academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen 518055China Center of Deep Sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Institue of geology Chinese Academy of Geological SciencesBeijing 100037China

Hydrothermal alteration of olivine greatly influences geodynamics and the recycling of volatiles(such as water and carbon)in subduction *** is an important component of geological fluids,and its influence on the hydrothermal alteration of olivine remains poorly *** this study,we performed experiments at 3.0–515℃ and 3.0 kbar(1 bar=10^(5)Pa)by reacting well homogenized mixtures of olivine and silica powders with saline solutions(0.5 mol L^(−1)NaCl).Silica greatly influences the reaction pathways,reaction rates,and molecular hydrogen(H_(2.)formation during olivine hydrothermal *** experiments at 3.0℃ and 3.0 kbar with mixtures of olivine and 10 wt%silica,olivine was replaced by serpentine and *** proportions of serpentine and talc were determined according to standard curves based on infrared spectroscopy *** 6.5%serpentine and 12.talc were produced after an experimental duration of 7 days,which had no change after a longer period(14 days).Compared to the kinetics in silica-free systems,the rates of olivine hydrothermal alteration in experiments with 10 wt%silica are much *** overall reaction is:4.5Forsterite+5.5SiO_(2.,aq+4H_(2.O=Serpentine+*** the addition of more silica(2. wt%and 40 wt%),olivine was transformed into *** rates of reaction were much faster,e.g.,for experiments with olivine and 2. wt%silica,43.of talc was produced after 14 days,which increased to 77%for experiments with 40 wt%silica over the same *** overall reaction is:3.orsterite+5SiO_(2.,aq+2._(2.O=*** experiments at 400–505℃ and 3.0 kbar,the promoting effect of silica on olivine hydrothermal alteration was also observed,which is closely associated with a decrease in Gibbs free energies of olivine hydrothermal *** 3.0℃ and 3.0 kbar,silica decreased H_(2.formed during olivine hydrothermal alteration by around an order of magnitude,resulting in an increase in oxygen *** on measured H_(2.,we calibrated ox

关键词： Olivine hydrothermal alteration Silica Serpentinization Hydrogen Serpentine

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Discovery of Eoarchean Meta-Dioritic Rocks in Anshan Area, China and Its geological Significance

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Journal of Earth Science 1999年第4期18卷 291-294页

作者： wan yusheng {2. Dunyi Li Huiming Yang Chonghui({3. of geology, {3. academy of geological Sciences, Beijing 10003.) institute of geology Chinese Academy of Geological SciencesBeijing 100037

In the Anshan area of Liaoning Province, an occurrence area of the oldest rocks in the world,the meta-dioritic rock of Eoarchaean has recently been found as enclaves in the 3. 8 Ga Dongshan banded trondhjemitic rock. It has relatively high contents of REE (w(∑REE) = 149. 3.10-6) and unmarked LREE enrichment over HREE (wn (La)/wa (Yb) = 6. 99). Eight analysed zircon grains yield a well-defined discordia with an upper intercept of 3. 65 Ga. Some of the data points give an important in formation of more ancient zircon existence in the rock. The rock shows unusually low ε(Nd, 3. 8 Ga) values of - 1. 15 to -1. 2. and large tDM age of 4. 15-4.16 Ga. The geological significance of the discovery is briefly discussed in this paper.

关键词： meta-dioritic rocks Nd isotope Eoarchaean Anshan

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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 {3. of geological Sciences, Beijing 10003., China) State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China Exploration and Development Research institute Tarim Oilfield Company 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..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.

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Chronoframe of Archaean in Anshan-Benxi Area,Liaoning Province,China

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Journal of Earth Science 1993年第1期12卷 35-40页

作者： wan yusheng Wu Jiashan {2. Dunyi Geng Yuansheng Song Biao{3. of geology , {3. academy of geological Sciences, Beijing 10003.

The Anshan- Benxi area is one of the important places of the Precambrian in the North China craton, in which a lot of old geological bodies were found, including the Baijiafen mylontized granitic gneiss of 3.8 Ga ,the Chentaigou gneissic granite of 3. Ga and the supracrustal rocks and associated granites of relatively younger ages .Based on the age data and other geological information obtained in recent yeais, mis paper establishes fourfold-divison scheme of the Archaean in the Anshan-Benxi area .The time boundaries are 2.5,2.8,3.2.and 3.6 Ga, corresponding to those recommended by the International Sub-commission on Precambrian Stratigraphy . This paper also discusses some questions related to the crustal evolution of the early history, and indicates that it is possible to find out more residual crustal materials of older than 2.8 Ga.

关键词： chronoframe of the Archaean - Anshan - Benxi area crustal evolution of the early history.

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Quartz-Ferberite Oxygen Isotope Geothermometer and Its geological Applications

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Acta Geologica Sinica(English Edition) 1992年第3期66卷 271-281页

作者： Ding Tiping liu Yushan wan Defang liu Zhijian Li Jincheng Zhang Guilan {3. of Mineral Deposits, chinese academy of {3. Sciences, Beijing institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing

Experiments for oxygen isotope exchange between ferberite and water were carried out and the followingequation on oxygen isotope fractionation between ferberite and water against temperature was obtained:Combining this equation with the equation of Clayton et al. (1972. on oxygen isotope fractionation be-tween quartz and water, an equation on oxygen isotope fractionation between quartz and ferberite was ob-tained:The Bigeleison-Mayer function method was used to calculate the oxygen isotope fractionation betweenquartz and ferberite. The theoretical curve obtained agrees with the experimental calibration results quite wellin the temperature range of *** above calibrated equation has been used in 5 world famous tungsten deposits to determine their tem-peratures of formation. The results show that the temperature range for an idividual deposit determined by thisgeothermometer agrees with those obtained from fluid inclusion determination and other isotopegeothermometers.

关键词： geothermometer oxygen isotope quartz--ferberite

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