【摘要】 <正> 一、地质、沉积、地貌背景 珠江口外西侧近岸海岛主要包括荷包岛,高栏岛,三灶岛,交杯沙滩,大、小杧洲岛,大、小横琴岛等。岛屿空间展布受燕山运动控制,主要表现为断裂及伴随的岩浆活动。本文仅涉及砂质沉积比较发育的高栏、三灶、大横琴和交杯沙,即“三岛一滩”。更多还原

【Abstract】 Along the western coast of the Zhujiang River Estuary there are a series of small, intermittently NE-distributed islands, adjoining the mainland shore at the west. They can be divided into two sedimentary types based on the grain-size analyses of the sandy bottom sediment collected from this area. One is called the terrigenous fine-sand deposit under a midlower energy condition, and is represented by the sedimentary facies of Sanzao Island and Jiaobei Beach. Another type belongs to the coarse to medium sand, near terrigenous deposit under a mid-high energy condition, and is represented by the sedimentary facies of Gaolan Island and Dahengqin Island.The principal factors affecting the sedimentary distribution in this area are the relief of the coast, the energy level of the water and the characters of the sediment supply; and the two sedimentary types are obviously resulted from the interaction of these factors. The first type is produced under the conditions of a relatively even relief, a weakly water energy and a suspended sand supply mainly from the River. On the contrary, the second appears in the places with a steeper relief, a higher water energy and a stronger erosion environment. And its sediment is mainly supplied by the granite remains on the neighbouring islands.更多还原