摘要： 海峡是不同于三角洲、陆架的一类独特沉积环境,具有特殊的沉积作用组合。海峡的形态多样,长度为几千米至数百千米,深度为几十米至上千米; 海峡由狭窄区域向两端逐渐过渡为相对开阔海区,开阔海区大多深度相比海峡更深; 海峡的狭窄区域横截面积小、流体流速最大,通常以侵蚀地貌为特征; 流体流经狭窄区域后,由于海峡横截面积增加,导致流速向两端开阔海区域锐减,并表现为沉积地貌。浅水海峡通常以潮流为最主要的沉积作用,其他的沉积物搬运方式包括单向的海流和重力流; 深水海峡则以海流和重力流为主。海峡高能区沉积以砾石滞留和发育交错层理为特征,低能区表现为泥质沉积并发育流水砂纹; 在低海平面时期,暴露的浅水海峡以河流沉积作用为主; 海平面上升过程中,河流逐渐演化为三角洲/河口湾、海湾和贯通的海峡。

关键词: 海峡沉积, 沉积环境, 潮流, 海流, 重力流

Abstract: The strait is distinguished from delta or shelf in having unique sedimentary processes and sediment distribution. Straits show a wide variety of shapes,with a length ranging from a few kilometers to several hundred kilometers and a depth ranging from several tens of meters to more than one kilometer. The strait shows a mouth shape toward open sea and becomes wider and deeper seaward. When ocean current flow through the narrow end of strait,the flow velocity increases and erosions occur here. After the flow through the narrowest part of strait,the oceanic currents enter a wider zone,causing a decreased flow velocity and deposition in this zone. Tidal processes are probably the most important transport agents for shallow-water strait. Other processes include uni-directional oceanic current and sediment gravity flow. Deep-water strait is dominated by oceanic currents and sediment gravity flows. High-energy zones predominantly comprise gravel lags and cross-bedding,whereas low-energy zone is featured by current ripples and muddy deposits. When sea level is low,the strait is exposed in which fluvial processes are dominant. During transgression,river evolves to delta/estuary,bay and strait.

Key words: strait deposit, sedimentary environment, tidal current, oceanic current, sediment gravity flow

中图分类号: 

• P512.2