An insight into shallow gas hydrates in the Dongsha area,South China Sea |
| |
Authors: | Bin Liu Jiangxin Chen Luis M. Pinheiro Li Yang Shengxuan Liu Yongxian Guan Haibin Song Nengyou Wu Huaning Xu Rui Yang |
| |
Affiliation: | Key Laboratory of Marine Mineral Resources, Ministry of Natural Resources, Guangzhou Marine Geological Survey,Guangzhou 510075, China;Key Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China;Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology (Qingdao),Qingdao 266237, China;Departamento de Geociências and Centre for Environmental and Marine Studies, Universidade de Aveiro, Aveiro 3800, Portugal;State Key laboratory of Marine Geology, Tongji University, Shanghai 200092, China |
| |
Abstract: | Previous studies of gas hydrate in the Dongsha area mainly focused on the deep-seated gas hydrates that have a high energy potential, but cared little about the shallow gas hydrates occurrences. Shallow gas hydrates have been confirmed by drill cores at three sites (GMGS2 08, GMGS2 09 and GMGS2 16) during the GMGS2 cruise, which occur as veins, blocky nodules or massive layers, at 8–30 m below the seafloor. Gas chimneys and faults observed on the seismic sections are the two main fluid migration pathways. The deep-seated gas hydrate and the shallow hydrate-bearing sediments are two main seals for the migrating gas. The occurrences of shallow gas hydrates are mainly controlled by the migration of fluid along shallow faults and the presence of deep-seated gas hydrates. Active gas leakage is taking place at a relatively high-flux state through the vent structures identified on the geophysical data at the seafloor, although without resulting in gas plumes easily detectable by acoustic methods. The presence of strong reflections on the high-resolution seismic profiles and dim or chaotic layers in the sub-bottom profiles are most likely good indicators of shallow gas hydrates in the Dongsha area. Active cold seeps, indicated by either gas plume or seepage vent, can also be used as indicators for neighboring shallow gas hydrates and the gas hydrate system that is highly dynamic in the Dongsha area. |
| |
Keywords: | shallow gas hydrate Dongsha cold seep fluid flow methane-derived authigenic carbonate South China Sea |
本文献已被 CNKI 万方数据 等数据库收录! |
| 点击此处可从《海洋学报(英文版)》浏览原始摘要信息 |
|
点击此处可从《海洋学报(英文版)》下载全文 |
|