南海北缘一统暗沙附近深水等深流沉积体系特征

利用高分辨率2D地震资料揭示南海北缘一统暗沙附近(水深700~1 000 m)发育海山相关的深水等深流沉积体系, 为南海北部陆缘深水洋流循环和深海动力学研究, 以及深水油气矿产资源勘探提供了新的资料.一统暗沙南、北两侧发育边缘侵蚀槽沟, 其中北缘的边缘槽沟可称为"环槽", 反映底流(可能属于南海中层水循环体系)自西向东流经海山.一套等深流沉积的伸长状-丘状漂积体沿环槽北岸发育.一统暗沙南侧和背侧还发育黏附型漂积体、南侧沉积区和补丁型漂积体.地震沉积记录显示该区稳定底流侵蚀-沉积活动可追溯至晚中新世早期. 

Deep-Water Contourite Depositional System in Vicinity of Yi'tong Shoal on Northern Margin of the South China Sea

Using high-resolution 2D seismic data, this study reveals the presence of a deep-water contourite depositional system that developed in vicinity of the Yi'tong Shoal (700-1 000 m depth), on the northern margin of the South China Sea. The development of a moat north of the Yi'tong Shoal indicates eastward flowing bottom currents, which might belong to the South China Sea Intermediate Water Circulation. Due to the coriolis deflection, an elongated-mounded drift is developed to the north of the moat. A marginal trough, a plastered drift and a deposition zone developed south of the Yi'tong Shoal, indicative of relatively weak hydrodynamics in the south side. A shadow zone downstream of the Yi'tong Shoal was generated where the currents slowed down, developing a depositional tail. Seismic stratigraphy shows that the initial development of the deep-water contourite depositional system was developed from the early Late Miocene (11.6 Ma).