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International Conference on Gas Hydrates (ICGH) (6th : 2008)

GEOCHEMICAL ANOMALY OF PORE WATERS AND IMPLICATIONS FOR GAS HYDRATE OCCURENCE IN THE SOUTH CHINA SEA Jiang, Shao-Yong; Yang, Tao; Ge, Lu; Yang, Jing-Hong; Wu, Neng-You; Liu, Jian; Zhang, Guang-Xue; Chen, Dao-Hua

Abstract

Except for direct drilling and sampling of marine gas hydrates, the occurrence of gas hydrates has been identified generally by inference from indirect evidence, derived from geological, geophysical, and geochemical data. In this paper, we intend to discuss the geochemical anomalies of pore waters and their implications for gas hydrate occurrence in the northern continental slope of the South China Sea. The molecular concentration and isotopic composition of methane in sediments can provide clues to gas sources, whereas ionic and isotopic compositions of pore waters, such as steep SO42- gradients, shallow SMI (sulfate-methane interface) depths; decreasing pore water chlorinity, and heavy oxygen isotopic compositions, are used to identify gas hydrate occurrence and the distribution and thickness of sediment layers containing gas hydrates. Other good geochemical indicators include anions and cations concentrations such as Br-, I-, PO43-, NH4+, Ca2+, Mg2+, Sr2+, B3+, Li+, and Ba2+ in pore waters. We also found that the very negative carbon isotopic compositions of dissolve inorganic carbon (DIC) in pore waters can serve as good indicators for gas hydrate occurrence. In the South China Sea, three most promising target areas for gas hydrates include the Dongsha, Shenhu, and Xisha Trough.

Item Metadata

Title
GEOCHEMICAL ANOMALY OF PORE WATERS AND IMPLICATIONS FOR GAS HYDRATE OCCURENCE IN THE SOUTH CHINA SEA
Creator
Jiang, Shao-Yong; Yang, Tao; Ge, Lu; Yang, Jing-Hong; Wu, Neng-You; Liu, Jian; Zhang, Guang-Xue; Chen, Dao-Hua
Contributor
University of British Columbia. Department of Chemical and Biological Engineering; International Conference on Gas Hydrates (6th : 2008 : Vancouver, B.C.)
Date Issued
2008-07
Description
Except for direct drilling and sampling of marine gas hydrates, the occurrence of gas hydrates has been identified generally by inference from indirect evidence, derived from geological, geophysical, and geochemical data. In this paper, we intend to discuss the geochemical anomalies of pore waters and their implications for gas hydrate occurrence in the northern continental slope of the South China Sea. The molecular concentration and isotopic composition of methane in sediments can provide clues to gas sources, whereas ionic and isotopic compositions of pore waters, such as steep SO42- gradients, shallow SMI (sulfate-methane interface) depths; decreasing pore water chlorinity, and heavy oxygen isotopic compositions, are used to identify gas hydrate occurrence and the distribution and thickness of sediment layers containing gas hydrates. Other good geochemical indicators include anions and cations concentrations such as Br-, I-, PO43-, NH4+, Ca2+, Mg2+, Sr2+, B3+, Li+, and Ba2+ in pore waters. We also found that the very negative carbon isotopic compositions of dissolve inorganic carbon (DIC) in pore waters can serve as good indicators for gas hydrate occurrence. In the South China Sea, three most promising target areas for gas hydrates include the Dongsha, Shenhu, and Xisha Trough.
Extent
100808 bytes
Subject
Gas hydrates; Isotopes; Geochemical indicators
Geographic Location
South China Sea
Genre
Conference Paper
Type
Text
File Format
application/pdf
Language
eng
Date Available
2008-07-22
Provider
Vancouver : University of British Columbia Library
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
DOI
10.14288/1.0041007
URI
http://hdl.handle.net/2429/1079
Affiliation
Non UBC
Citation
Jiang, Shao-Yong; Yang, Tao; Ge, Lu; Yang, Jing-Hong; Wu, Neng-You; Liu, Jian; Zhang, Guang-Xue; Chen, Dao-Hua. 2008. GEOCHEMICAL ANOMALY OF PORE WATERS AND IMPLICATIONS FOR GAS HYDRATE OCCURENCE IN THE SOUTH CHINA SEA. Proceedings of the 6th International Conference on Gas Hydrates (ICGH 2008), Vancouver, British Columbia, CANADA, July 6-10, 2008.
Peer Review Status
Unreviewed
Copyright Holder
Jiang, Shao-Yong
Rights URI
http://creativecommons.org/licenses/by-nc-nd/4.0/
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Attribution-NonCommercial-NoDerivatives 4.0 International