摘要
海底峡谷、高弯度水道等深水沉积单元中的流体活动方式是人们关注的热点。本次研究利用高分辨地震资料,结合地形地貌特征对台湾峡谷中段的沉积特征及流体活动方式进行初步探讨。台湾峡谷中段发育内堤岸(inner levee),它成层性好、地层产状倾斜,地震反射特征与峡谷西岸和下覆滑塌体明显不同,内部结构表现为逐级上超的特征,以侧向加积为主。曲流河和深水高弯度水道的点坝均发育于河(水)道拐弯处,由于离心力作用,沉积物在凸岸堆积形成点坝。该内堤岸位于峡谷中段直线型地段,不具备形成点坝的地形地貌条件,综合分析认为该内堤岸是由垂直于峡谷轴向、自西向东的底流与沿峡谷向下的重力流交互作用形成的。
Fluid activity in the deep-water sedimentary unit of the high sinuous submarine channels, sut）marine canyons are the focus nowadays. This study uses high-resolution seismic data, combined with the geomorphologic features to discuss the sedimentary characteristics and fluid mechanism in the middle segment of the Taiwan Canyon. There is an inner levee located in the middle Taiwan Canyon. The internal structure of this inner levee is characterized by obviously onlap and lateral accretion. In meandering rivers and high sinuous submarine channels, due to the change of geomorphologic or the decrease of slope, the sediment started to unload. When it went through the bend, with the action of centrifugal force, massive sediment accumulated at the convex bank. Non-similar with the rivers and high sinuous submarine channels, the inner levee is located in the straight segment of the middle canyon, where has no geomorphologic condition to form the point bars. The inner levee can be interpreted as the product of interaction between down-and along-slope processes.
出处
《地质论评》
CAS
CSCD
北大核心
2013年第5期845-852,共8页
Geological Review
基金
国家自然科学基金资助项目(编号40972077)的成果
关键词
内堤岸
重力流
底流
交互作用
流体机制
台湾峡谷
inner levee
gravity current
bottom current
interaction
fluid mechanism
Taiwan Canyon
