中国科学院机构知识库网格系统: Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China

Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China

文献类型：期刊论文


作者	Cao, MingJian 1; Qin, KeZhang 1; Li, GuangMing 1; Evans, Noreen J.2; Jin, LuYing 1,3
刊名	GEOCHIMICA ET COSMOCHIMICA ACTA
出版日期	2014-09-15
卷号	141 页码:179-198
ISSN号	0016-7037
DOI	10.1016/j.gca.2014.06.018
文献子类	Article
英文摘要	Methane is widely developed in hydrothermal fluids from reduced porphyry copper deposits, but its origin remains enigmatic. The occurrence of methane in fluid inclusions at the Late Carboniferous Baogutu reduced porphyry copper deposit in western Junggar, Xinjiang, NW-China, presents an excellent opportunity to address this problem. A systematic study including fluid inclusion Laser-Raman and CO2-CH4 carbon isotope analyses, igneous and hydrothermal mineral H-O isotope analyses, and in situ major, trace element and Sr isotopic analyses of hydrothermal epidote was conducted to constrain the origin of CH4 and CH4-rich fluids. The delta H-2 and delta O-18 of water in equilibrium with igneous biotite ranges from -65.0 parts per thousand to -66.0 parts per thousand and +7.2 parts per thousand to +7.4 parts per thousand, respectively, indicating notable degassing of probably supercritical fluids in the magma chamber. The wide range of delta H-2 (-58.0 parts per thousand to -107.0 parts per thousand, n = 23) for water within quartz suggests the existence of significant hydrothermal fluid boiling. Water-rock interaction is the most likely mechanism leading to the wide range of delta O-18 values for water in vein quartz with water/rock ratios (wt.% in O) of 0.15 to 0.75 and 0.13 to 0.46 for a closed and open system, respectively. Detailed Laser-Raman analyses indicate CO2 in apatite included in granodiorite porphyry phenocrystic biotite that records the carbon species of the early stage magmatic stage, whereas later hydrothermal fluids containing CH4 with trace or without CO2 are found in inclusions of vein quartz. We propose that CH4 is probably transformed from CO2 by Fischer-Tropsch type reactions at 500 degrees C, assumed from CO2-CH4 C isotope equilibrium. The (Sr-87/Sr-86)(i) of hydrothermal epidote yields values of 0.70369-0.70404, consistent with that reported for the whole rocks. The delta C-13(CH4) (-28.6 parts per thousand to -22.6 parts per thousand) and delta H-2(CH4) (-108.0 parts per thousand to -59.5 parts per thousand) are characteristic of abiogenic methane. The measured delta C-13(CO2) shows a slightly depleted C-13 (-13.5 parts per thousand to -7.2 parts per thousand) relative to upper mantle (-6 parts per thousand), probably due to the combined effects of minor (less than 0.5%) sedimentary organic matter contamination in the mantle and carbon isotope fractionation occurring during late degassing.
WOS关键词	HYDROGEN ISOTOPE FRACTIONATION ; ALKALINE IGNEOUS ROCKS ; MO-AU DEPOSIT ; ZIRCON U-PB ; CARBON-ISOTOPE ; FLUID INCLUSIONS ; RIDGE SUBDUCTION ; TRACE-ELEMENT ; CU DEPOSIT ; HYDROTHERMAL SYSTEMS
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000341926100011
资助机构	National Natural Sciences Foundation of China(41390444) ; National Natural Sciences Foundation of China(41390444) ; China Postdoctoral Science Foundation(2014M550834) ; China Postdoctoral Science Foundation(2014M550834) ; Society of Economic Geologists Hugh McKinstry Fund ; Society of Economic Geologists Hugh McKinstry Fund ; National Natural Sciences Foundation of China(41390444) ; National Natural Sciences Foundation of China(41390444) ; China Postdoctoral Science Foundation(2014M550834) ; China Postdoctoral Science Foundation(2014M550834) ; Society of Economic Geologists Hugh McKinstry Fund ; Society of Economic Geologists Hugh McKinstry Fund ; National Natural Sciences Foundation of China(41390444) ; National Natural Sciences Foundation of China(41390444) ; China Postdoctoral Science Foundation(2014M550834) ; China Postdoctoral Science Foundation(2014M550834) ; Society of Economic Geologists Hugh McKinstry Fund ; Society of Economic Geologists Hugh McKinstry Fund ; National Natural Sciences Foundation of China(41390444) ; National Natural Sciences Foundation of China(41390444) ; China Postdoctoral Science Foundation(2014M550834) ; China Postdoctoral Science Foundation(2014M550834) ; Society of Economic Geologists Hugh McKinstry Fund ; Society of Economic Geologists Hugh McKinstry Fund
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84892]
专题	中国科学院地质与地球物理研究所
通讯作者	Cao, MingJian
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Curtin Univ, Dept Appl Geol, John Laeter Ctr Isotope Res, Perth, WA 6845, Australia 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Cao, MingJian,Qin, KeZhang,Li, GuangMing,et al. Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2014,141:179-198.
APA	Cao, MingJian,Qin, KeZhang,Li, GuangMing,Evans, Noreen J.,&Jin, LuYing.(2014).Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China.GEOCHIMICA ET COSMOCHIMICA ACTA,141,179-198.
MLA	Cao, MingJian,et al."Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China".GEOCHIMICA ET COSMOCHIMICA ACTA 141(2014):179-198.

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来源：地质与地球物理研究所

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Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China

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