Bottom simulating reflector and gas seepage in Okinawa Trough: Evidence of gas hydrate in an active back-arc basin

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	Bottom simulating reflector and gas seepage in Okinawa Trough: Evidence of gas hydrate in an active back-arc basin
	Luan Xiwu 1; Wang, Kelin 2; Hyndman, Roy 2; Willoughby, Eleanor 2
刊名	JOURNAL OF CHINA UNIVERSITY OF GEOSCIENCES
	2008-04-01
卷号	19 期号:2 页码:152-161
关键词	Gas Hydrate Bsr Gas Seepage Back-arc Basin Formation Mechanism
ISSN号	1002-0705
文献子类	Article
英文摘要	To look for gas hydrate, 22 multi-channel and 3 single-channel seismic lines on the East China Sea (ECS) shelf slope and at the bottom of the Okinawa Trough were examined. It was found that there was indeed bottom simulating reflector (BSR) occurrence, but it is very rare. Besides several BSRs, a gas seepage was also found. As shown by the data, both the BSR and gas seepage are all related with local geological structures, such as mud diapir, anticline, and fault-controlled graben-like structure. However, similar structural "anomalies" are quite common in the tectonically very active Okinawa Trough region, but very few of them have developed BSR or gas seepage. The article points out that the main reason is probably the low concentration of organic carbon of the sediment in this area. It was speculated that the rare occurrence of gas hydrates in this region is governed by structure-controlled fluid flow. Numerous faults and fractures form a network of high-permeability channels in the sediment and highly fractured igneous basement to allow fluid circulation and ventilation. Fluid flow in this tectonic environment is driven primarily by thermal buoyancy and takes place on a wide range of spatial scales. The fluid flow may play two roles to facilitate hydrate formation: to help gather enough methane into a small area and to modulate the thermal regime.; To look for gas hydrate, 22 multi-channel and 3 single-channel seismic lines on the East China Sea (ECS) shelf slope and at the bottom of the Okinawa Trough were examined. It was found that there was indeed bottom simulating reflector (BSR) occurrence, but it is very rare. Besides several BSRs, a gas seepage was also found. As shown by the data, both the BSR and gas seepage are all related with local geological structures, such as mud diapir, anticline, and fault-controlled graben-like structure. However, similar structural "anomalies" are quite common in the tectonically very active Okinawa Trough region, but very few of them have developed BSR or gas seepage. The article points out that the main reason is probably the low concentration of organic carbon of the sediment in this area. It was speculated that the rare occurrence of gas hydrates in this region is governed by structure-controlled fluid flow. Numerous faults and fractures form a network of high-permeability channels in the sediment and highly fractured igneous basement to allow fluid circulation and ventilation. Fluid flow in this tectonic environment is driven primarily by thermal buoyancy and takes place on a wide range of spatial scales. The fluid flow may play two roles to facilitate hydrate formation: to help gather enough methane into a small area and to modulate the thermal regime.
语种	英语
WOS记录号	WOS:000255488700005
公开日期	2010-12-30
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/6189]
专题	海洋研究所_海洋地质与环境重点实验室
作者单位	1.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Geol Survey Canada, Pacific Geosci Ctr, Sidney, BC V8L 4B2, Canada
推荐引用方式 GB/T 7714	Luan Xiwu,Wang, Kelin,Hyndman, Roy,et al. Bottom simulating reflector and gas seepage in Okinawa Trough: Evidence of gas hydrate in an active back-arc basin[J]. JOURNAL OF CHINA UNIVERSITY OF GEOSCIENCES,2008,19(2):152-161.
APA	Luan Xiwu,Wang, Kelin,Hyndman, Roy,&Willoughby, Eleanor.(2008).Bottom simulating reflector and gas seepage in Okinawa Trough: Evidence of gas hydrate in an active back-arc basin.JOURNAL OF CHINA UNIVERSITY OF GEOSCIENCES,19(2),152-161.
MLA	Luan Xiwu,et al."Bottom simulating reflector and gas seepage in Okinawa Trough: Evidence of gas hydrate in an active back-arc basin".JOURNAL OF CHINA UNIVERSITY OF GEOSCIENCES 19.2(2008):152-161.