长江上游的心滩--重庆珊瑚坝现代沉积考察

一、概述珊瑚坝位在“四周千嶂合,三面大江流的”重庆市区附近,在嘉陵江与长江合流之上约四公里,地处长江主航道近凹岸一侧(图1)。砂坝长轴与主流向一致,长约1.1公里,面积0.275平方公里。沙坝头部比尾部略显宽缓。据河流分类应属上游河流的心滩沉积。

A CHANNEL BAR IN THE UPPER REACHES OF THE CHANGJIANG RIVER-RESEARCH ON RECENT SEDIMENT OF SHANHUBA IN CHONGQING,SICHUAN PROVINCE

Shanhuba in Chongqing is a channel bar in the upper reaches of the Changjiang River. In the different parts of the bar, there are a lot of different forms of stratification and bedding plane structure. The various ripple marks on the surface of the bar are comparable to those in the near-shore intertidal area. The typical"inverted V"sturcture on the cross-strati- fication of the channel bar is especially better than that on beach barrier and beach cusp. The sedimentary model established by studying the relationship between the bedding structure and grain-size cyclothems of the channel bar and its sedimentary history, can be used to look for fluvial sedimentary deposits. The Shanhuba channel bar in Chongqing will possibly be one of the best localities for making geological tours and researches on present channel bar.