Seabed domes with circular depressions in the North Yellow Sea  

作　　者：WANG Bing ZHANG Xin LUAN Zhendong CHEN Chang’an YAN Jun 王冰;张鑫;栾振东;陈长安;阎军

机构地区：[1]CAS Key Laboratory of Marine Geology and Environment & Center of Deep Sea Research,Institute of Oceanology,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology

出　　处：《Journal of Oceanology and Limnology》2018年第6期2154-2165,共12页海洋湖沼学报（英文）

基　　金：Supported by the Strategic Priority Research Program,CAS(No.XDA19060402);the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1606401);the International Partnership for Innovative Team Program(No.20140491526);the Chinese Academy of Sciences,and the Taishan Scholar Project Funding(No.tspd20161007)

摘　　要：Numerous isolated shallow seabed domes with depressions were discovered in the North Yellow Sea in a high-resolution multibeam echosounder survey. Twelve domes were located within a 11 km by 17 km survey area. The domes in this area were between 0.1 m and 1.0 m high with diameters ranging from 250 to 1 700 m. They were surrounded by corresponding depressions and displayed characteristic shapes ranging from circular to elliptical. The acoustic anomalies displayed on the high resolution sub-bottom profile images demonstrated that shallow gas accumulated just beneath these domes, suggesting that the migration and accumulation of the shallow gas caused the formation of these features. Accumulation atop the seabed domes and erosion within the depressions, as indicated by the lithological features of the sediment cores, suggested that seabed bottom currents also played a role in the formation and evolution of these features. In addition, the simultaneous decrease in the chlorite and sulfate content in core d pore water samples confirmed the presence of submarine fresh/brackish groundwater, which is of interest for hydrological budgets and may be a significant component of the regional hydrologic balance. Our findings suggested that shallow gas accumulation and migration are likely coupled to localized groundwater discharge at this domed site.Numerous isolated shallow seabed domes with depressions were discovered in the North Yellow Sea in a high-resolution multibeam echosounder survey. Twelve domes were located within a 11 km by 17 km survey area. The domes in this area were between 0.1 m and 1.0 m high with diameters ranging from 250 to 1 700 m. They were surrounded by corresponding depressions and displayed characteristic shapes ranging from circular to elliptical. The acoustic anomalies displayed on the high resolution sub-bottom profile images demonstrated that shallow gas accumulated just beneath these domes, suggesting that the migration and accumulation of the shallow gas caused the formation of these features. Accumulation atop the seabed domes and erosion within the depressions, as indicated by the lithological features of the sediment cores, suggested that seabed bottom currents also played a role in the formation and evolution of these features. In addition, the simultaneous decrease in the chlorite and sulfate content in core d pore water samples confirmed the presence of submarine fresh/brackish groundwater, which is of interest for hydrological budgets and may be a significant component of the regional hydrologic balance. Our findings suggested that shallow gas accumulation and migration are likely coupled to localized groundwater discharge at this domed site.

关 键 词：SEABED DOME shallow gas North Yellow Sea submarine fresh/brackish groundwater 

分 类 号：P[天文地球]