Authigenic carbonates from seeps on the northern continental slope of the South China Sea: New insights into fluid sources and geochronology

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 中科院边缘海地质重点实验室

	Authigenic carbonates from seeps on the northern continental slope of the South China Sea: New insights into fluid sources and geochronology
	[Tong, Hongpeng ; Feng, Dong ; Chen, Zhong ; Chen, Duofu] Chinese Acad Sci, South China Sea Inst Oceanol, CAS Key Lab Marginal Sea Geol, Guangzhou 510301, Guangdong, Peoples R China ; [Tong, Hongpeng ; Chen, Duofu] Chinese Acad Sci, Guangzhou Inst Geochem, CAS Key Lab Marginal Sea Geol, Guangzhou 510640, Guangdong, Peoples R China ; [Cheng, Hai] Xi An Jiao Tong Univ, Inst Global Environm Change, Xian 710049, Peoples R China ; [Cheng, Hai ; Min, Angela G. ; Edwards, R. Lawrence] Univ Minnesota, Dept Earth Sci, Minneapolis, MN 55455 USA ; [Yang, Shengxiong ; Wang, Hongbin] Guangzhou Marine Geol Survey, Guangzhou 510075, Guangdong, Peoples R China
刊名	MARINE AND PETROLEUM GEOLOGY
	2013
卷号	43 页码:260-271
关键词	Seep carbonate Fluid source U/Th age Carbon and oxygen isotope Sr-87/Sr-86 South China Sea
ISSN号	0264-8172
通讯作者	feng@scsio.ac.cn ; cdf@gig.ac.cn
中文摘要	Seep carbonates represent excellent archives of seepage activities near seafloors. In order to provide insights on sources of seeping fluids, stable carbon and oxygen isotopes and Sr-87/Sr-86 ratios were applied to seep carbonates from Shenhu, SW Dongsha, and NE Dongsha on the northern continental slope of the South China Sea. U/Th dating was selected to constrain the time involved in carbonate formation and the potential driving force. The delta C-13 values of the Shenhu and NE Dongsha carbonates vary from -52.3 parts per thousand to -32.6 parts per thousand (V-PDB), indicating that biogenic methane is the primary carbon source at both locations. The delta C-13 values of the SW Dongsha carbonates are much higher, ranging from -18.8 parts per thousand to -11.parts per thousand (V-PDB), suggesting that thermogenic methane is the predominant carbon source in this region. A relatively deep origin of thermogenic methane for the SW Dongsha seeps is also supported by somewhat lower Sr-87/Sr-86 ratios of the samples (from 0.709025 to 0.709097). The delta O-18 values of the Shenhu and NE Dongsha carbonates vary from 1.4%. to 5.1%. (V-PDB), while the delta O-18 values of the SW Dongsha carbonates range from 2.5%. to 3.4%. (V-PDB). Many samples from Shenhu and NE Dongsha demonstrate an O-18-enriched fluid source that most likely originated from waters released from the dissociation of locally abundant gas hydrate. U/Th ages of the Shenhu carbonates show a large range from 330 ka to 152 ka BP and the NE Dongsha carbonates have ages from 77 ka to 63 ka BP. Interestingly, U/Th ages of most samples are either within times of sea-level lowstands or correspond to periods when the sea-level was falling. Taken together, our data suggest that in the South China Sea gas hydrate dissociation during sea-level lowstands or falling stages resulted from reduced hydrastastic pressures, which in turn enhanced the seep activities and promoted the formation of authigenic carbonates close to the seafloor. (C) 2013 Elsevier Ltd. All rights reserved.
学科主题	Geosciences, Multidisciplinary
资助信息	This study was partially supported by the NSFC (Grants: 91028012 and 91228206), the Knowledge Innovation Program of CAS (KZCX2-YW-GJ03), 973 Program (2009CB219506), "Hundred Talents Program" of CAS, and GIGCAS 135 project Y234021001. We are grateful to Y. Liu, W.F. Deng, and F.Y. Wang (all GIG, CAS) for help with the analyses of the samples. Furthermore, we thank Dr. Pufahl and three anonymous reviewers for their helpful comments that greatly improved an earlier version of this manuscript.
原文出处	ELSEVIER SCI LTD
语种	英语
WOS记录号	WOS:000318831400016
公开日期	2015-01-22
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/11131]
专题	南海海洋研究所_中科院边缘海地质重点实验室
推荐引用方式 GB/T 7714	[Tong, Hongpeng,Feng, Dong,Chen, Zhong,et al. Authigenic carbonates from seeps on the northern continental slope of the South China Sea: New insights into fluid sources and geochronology[J]. MARINE AND PETROLEUM GEOLOGY,2013,43:260-271.
APA	[Tong, Hongpeng.,Feng, Dong.,Chen, Zhong.,Chen, Duofu] Chinese Acad Sci, South China Sea Inst Oceanol, CAS Key Lab Marginal Sea Geol, Guangzhou 510301, Guangdong, Peoples R China.,[Tong, Hongpeng.,...&Wang, Hongbin] Guangzhou Marine Geol Survey, Guangzhou 510075, Guangdong, Peoples R China.(2013).Authigenic carbonates from seeps on the northern continental slope of the South China Sea: New insights into fluid sources and geochronology.MARINE AND PETROLEUM GEOLOGY,43,260-271.
MLA	[Tong, Hongpeng,et al."Authigenic carbonates from seeps on the northern continental slope of the South China Sea: New insights into fluid sources and geochronology".MARINE AND PETROLEUM GEOLOGY 43(2013):260-271.