Sedimentary geochemical response to gas hydrate episodic release on the northeastern slope of the South China Sea

被引：4

作者：

Chen F. ^{[1
]}

Lu H. ^{[1
]}

Liu J. ^{[1
]}

Zhuang C. ^{[1
]}

Wu C. ^{[1
]}

Cao J. ^{[1
]}

Zhou Y. ^{[1
]}

Liu G. ^{[1
]}

机构：

[1] Key Laboratory of Marine Mineral Resources, MLR, Guangzhou Marine Geologic Survey, Guangzhou

来源：

Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2016年 / 41卷 / 10期

关键词：

Authigenic carbonate; Carbon isotope; Gas hydrate episodic release; Marine geology; Soupy structure;

D O I：

10.3799/dqkx.2016.120

中图分类号：

学科分类号：

摘要：

The resource of gas hydrate in South China Sea is plentiful. It redound to resource development by investigating how the gas hydrate decompose. A sedimentology and geochemistry study has been done in gas-hydrate-bearing borehole sediment collected at site GMGS08 within the gas hydrate drilling area in the northeastern South China Sea. Results show that 11 layers of authigenic carbonate and bivalve bioclast, and 2 layers of carbonate limestone are distributed from top to bottom in hole GMGS08. Authigenic carbonate and bivalve bioclast primarily occurred in soupy structure sediments with high water content. The δ13C values of authigenic carbonate ranged from -41.36×10-3 to -56.74×10-3 except one sample with a higher δ13C value of -38.85×10-3, and the δ18O values were apparently heavy ranging from 2.94×10-3 to 5.37×10-3, suggesting they were attributed to gas hydrate dissociation via microbial anaerobic oxidation of methane, which was predominantly biogenic gas. The δ13C values of organic carbon varied from -21.33×10-3 to -82.44×10-3, in which the δ13C negative excursion intervals corresponded to authigenic carbonate layers. According to the distribution of authigenic carbonate, it is concluded that at least 6 episodes of gas hydrate release existed in geologic record, and the varying sizes of authigenic carbonate among the layers indicated the intensity of methane flux in each episode was different. © 2016, Editorial Department of Earth Science. All right reserved.

引用

页码：1619 / 1629

页数：10

共 25 条

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