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Geochemical characteristics and applications of 18α(H)-neohopanes and 17α(H)-diahopanes

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chinese Science Bulletin 2000年第19期45卷 1742-1748页

作者： WANG Chunjiang, FU Jiamo, SHENG Guoying, XIAO Qianhua, LI Jinyou, ZHANG Yali & PIAO Mingzhi1. Slate Key Laboratory of Organic geochemistry, guangzhou {2. of geochemistry, chinese academy of sciences. Guang/hou 51064., China 2. Department of Geosciences, Petroleum University, Beijing 102.00, China 3. {2. of Petroleum Exploration and Exploitation, Liaohe Bureau of Petroleum Exploration, Panjin 2.0000, China State Key Laboratory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Department of Geosciences Petroleum University Beijing China institute of Petroleum Exploration and Exploitation Liaohe Bureau of Petroleum Exploration Panjin China

Distributions and geochemical significances of 18α(H)-neohopanes and of 17α(H)-diahopanes in oils from west Xialiaohe depression of the Bohai Bay Basin have been studied. Relative abundance of 18α(H)-neohopanes and of 17α(H)-diahopanes can be effectively used as maturity parameters, in a range of medium-high mature stage, based on consideration on sedimentary-organic facies of source rocks. With a dual geochemical significance of maturity and sedimentary-organic facies, neohopane and diahopane parameters can be well used in oil-source correlation and in petroleum population division. Formation, primary concentration and preservation of precursors of rearranged hopanes are closely related to depositional conditions such as Eh-pH and clays content. A series of probable diahopanes (series D) was detected in the oils, which exhibits a similar distribution pattern and geochemical behavior as that of 17α(H)-diahopanes (series B).

关键词： 18α(H)-neohopane 17α(H)-diahopane maturity sedimentary-organic facies.

Thermodynamic Modelling of Ore-Forming Mechanism of the Changkeng Gold-Silver Deposits in Guangdong Province

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Acta Geologica Sinica(English Edition) 1997年第4期71卷 433-445页

作者： Zhang Sheng, Li Tongjin and Wang Liankuiguangzhou institute of {2., chinese academy of sciencesWushan, guangzhou 51064. guangzhou institute of {2. Chinese Academy of Sciences Wushan Guangzhou 510640 [?]Zhang Sheng Born in 1967 graduated from China University of Geosciences (Wuhan) in 1989 and acquired the master's and doctor's degrees in chinese academy of sciences (CAS) and Guangdong {2. of geochemistry CAS in 1992 and 1996 successively. He is now engaged in studies of metallic ore deposits geochemical thermodynamics and experimental geochemistry.

The Changkeng gold-silver deposits consist of a sediment-hosted, disseminated gold deposit and a replacement-type silver deposit. The mineralizations of gold and silver are zoned and closely related to the silicification of carbonate and clastic rocks, so that siliceous ores dominate in the deposit. The mineralizing temperature ranges mainly from 300 to 170℃, and K+, Na+, Ca2., Mg2., and Cl- are the major ions in the ore-forming fluid. Calculations of distribution of metal complexes show that gold is mainly transported by hydrosulphide complexes, but chloride complexes of silver, iron, lead, and zinc, which are transformed into hydroxyl and hydrosulphide complexes under neutral to weak-alkaline circumstances in the late stage, predominate in the ore-forming solutions. Water-rock interaction is confirmed to be the effective mechanism for the formation of silver ores by computer modelling of reaction of hydrothermal solution with carbonate rocks. The solubility analyses demonstrate that the precipitation of gold and silver-bearing minerals taking place under weak-acid conditions and near-neutral to weak-alkaline conditions, respectively, is the main or favourable factor for the ore zonation and separation between gold and silver.

关键词： computer modelling transport form of element water-rock interaction mineral precipitation gold-silver deposit Guangdong province

A preliminary analysis on lithospheric thickness and crustal ages in central basin of South China Sea

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Acta Oceanologica Sinica 1997年第1期16卷 85-107页

作者： Chen Xue and Lin Jinfeng South China Sea institute of Oceanology, the chinese academy of sciences, {2. 510301, China South China Sea institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China

The models about lithospheric thickness and thermal conduction inside the lithosphere and the top layer of the asthenosphere have been proposed in this study for four type regions: the midoceanic ridge, the extinct spreading ridge, the lithospheric fault fissure and the mouth of the extinct submarine volcanoes which are in deep sea bottom. The solutions of the models are found to be the same. The formulas of temperature distribution inside the lithosphere and the top layer of the asthenosphere, the lithospheric thicknesses to the heat flow and the crustal ages to the heat flow are obtained. The crustal ages and the lithospheric thicknesses of the central basin are calculated. And they are used to draw the lithospheric thicknesses and crustal ages maps of the central basin (in this paper both the central basin and the basin are the central basin of the South China Sea). According to their characteristics, the central basin is divided into three regions. The lithospheric thicknesses, crustal ages and heat flow distribution characteristics are discussed respectively. The formation and evolution of the South China Sea are analysed and it is thought that the South China Sea has undergone three episode-seafloor spreadings.

关键词： Thermal conduction equation lithospheric thickness crustal age evolution

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Acta Geologica Sinica(English Edition) 1995年第3期69卷 273-287页

作者： Wang Liankui, Zhang Shaoli, Xu Wenxin, Liang Yuelong, Deng Gaoqiang, and Sha Liankunguangzhou Branch, institute of {2., chinese academy of sciences, guangzhou, Guangdong Jiang M inxi guangzhou Branch Institute of Geochemistry

The traditional idea proposes that granites on the east and west coasts of the Pacific Ocean are different. According to field investigations of the geology of the western United States coupled with the authors' long-term studies on granites in South China, granites both in eastern China and in the western United States are similar.

关键词： Similarities Between Granites on the East and West Coasts of the Pacific Ocean Ruby West

Interactions of Copper, Evaporite, and Organic Matter and Genesis of Sandstone-Hosted Copper Deposits in the Chuxiong Basin, Yunnan Province

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Acta Geologica Sinica(English Edition) 1996年第4期70卷 407-419页

作者： Zhuang Hanping, institute of geochemistry,{2., Guiyang, GuizhouRan Chongying, He Mingqin, Geology Department, Kunming institute of Technology, Kunming, Yunnanand Lu Jialan guangzhou institute of geochemistry,{2., Guangdong

Studies on organic geochemistry indicate that the origin, type and maturity of organic matter are different among coal-bearing, copper-bearing and evaporite formations in the Mesozoic continental Chuxiong Basin, Yunnan, China. A mechanism has been proposed that (1) during the diagenetic mineralization stage the short-chain organic acids dervied from kerogen played an important role in remobilizing copper from source beds, while oils acted as important carrier of copper, and that (2. during the transformation or remolding mineralization stage, meteoric water leached the evaporite layers and formed downward-percolating oxidizing SO42.rich fluids; meanwhile, the copper-bearing fluids migrating upwards along growth faults from the basement was contaminated by the coal-bearing series on the way and formed reducing organic-rich fluids; oxidation-reduction occurred and sulfides formed when the two kinds of fluids met within sandstones.

关键词： sandstone-hosted copper deposit organic matter evaporite organic geochemistry Chuxiong basin

Denitrification in Qi'ao Island coastal zone,the Zhujiang Estuary in China

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Acta Oceanologica Sinica 2009年第1期28卷 37-46页

作者： WANG Hu ZHOU Huaiyang PENG Xiaotong YANG Qunhui QIN Chaomei YIN Xijie CHEN Guangqian guangzhou institute of {2. Chinese Academy of Sciences Guangzhou 510640 China State Key Laboratory. of Marine Geology Tongji University Shanghai 200092 China Graduate University of chinese academy of sciences Beijing 100049 China

Samples of sediments and the overlying water were collected in the Qi＇ao Island coastal zone,the Zhujiang（Pearl River） Estuary（ZE）.Denitrification rates,sediment oxygen demand（SOD）,and fluxes of inorganic nitrogen compounds were investigated with N2.flux method,using a self-designed continuous flow through and auto-sampling *** results indicate that the denitrification rates varied between 2.2.and 908 μmol/（m2.h） with an average of 499 μmol /（m2.h）.During incubation,the sediments absorbed dissolved oxygen in the overlying water with SOD ranging from 300 to 2.363 μmol/（m2.h）.The denitrification rates were highly correlated with the SOD（r2.0.77） regardless of the NO-3＋NO-2.concentrations in the overlying water,organic carbon contents in sediments and water temperature,suggesting that the SOD was probably the main environmental factor controlling the denitrification in the Qi＇ao Island coastal *** was a net flux of NO-3＋NO-2.into the sediments from the overlying *** NH＋4 flux from sediments into water as the result of mineralization was between 12.3 and 2.0.3 μmol/（m2.h）,which seems limited by both organic carbon content in sediment and dissolved oxygen concentration in the overlying water.

关键词： denitrification N2.flux SOD inorganic nitrogen compound Qi' ao Island coastal zone Zhu-jiang Estuary

Zircon SHRIMP U-Pb dating for the Cangshuipu volcanic rocks and its implications for the lower boundary age of the Nanhua strata in South China

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Science Bulletin 2003年第16期48卷 1663-1669页

作者： WANG Jian1, LI Xianhua2. DUAN Taizhong3, LIU Dunyi4, SONG Biao4, LI Zhongxiong1 & GAO Yonghua5 1. Chengdu institute of Geology and Mineral Resources, China Geologi-cal Survey, Chengdu 610082. China 2. guangzhou institute of geochemistry,{2., guangzhou 51064., China 3. Colorado School of Mines, Golden, CO 80401-1887, USA (Present address: Marathon Oil Company, Houston, TX 77056-2.2., USA) 4. institute of Geology, chinese academy of Geological sciences, Bei-jing 100037, China 5. Graduate School of the chinese academy of Geological sciences, Beijing 100037, China Correspondence should be addressed to Wang Jian (e-mail: jianwang@ ***) Chengdu institute of Geology and Mineral Resources China Geological Survey Chengdu 610082 China guangzhou institute of {2. Chinese Academy of Sciences Guangzhou 510640 China Colorado School of Mines Golden CO 80401-1887 USA institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China Graduate School of the chinese academy of Geological {2. Beijing 100037 China

The continental volcanic rocks and volcaniclas-tic sedimentary conglomerates of the Cangshuipu Formation occur well in Yiyang of Hunan Province, consisting of a wedge-shaped succession of Neoproterozoic strata that over-lie with high-angle unconformity the flysch turbidites of the Lengjiaxi Group in the Upper Mesoproterozoic Eonothem. SHRIMP zircon U-Pb dating gives a weighted mean age of 814 12.Ma for the dacitic volcanic agglomerates from the lowest part of the volcanic rocks in the Cangshuipu Forma-tion. This age is younger than previously reported values of 92.—933 Ma for the volcanic rocks from the Cangshuipu Formation. Our new dating represents the lower boundary age of the Neoproterozoic System in the studied area. The younger age for the Cangshuipu volcanic rocks is supported by the following observations: （1） Lower Neoproterozoic strata （814—1000 Ma） are missing in the studied area; （2. the Nanhua rift system was initiated at about 82. Ma; and （3） an age of82. Ma may be taken as the lower boundary tim-ing of the Nanhua System （even Neoproterozoic） in South China.

关键词： Zicon U-Pb dating Neoproterozoic volcanics rift basin Nanhua System.