庐山东南麓下岸角剖面沉积与环境

Deposition and environment of Xiaanjiao section at the southeastern foot of Lushan mountain

由粒度分布特征、岩相特征恢复了下岸角剖面地层的沉积环境：该剖面地层以曲流河河道沉积为主，间有滨湖和滞水洼地沉积．用粒度参数确定了剖面中各地层沉积时的水流强度，借ＳｕｍｍｏｏｎＳＡ的经验公式恢复了形成几层冲积层的古河流的水文参数．粒度参数、水流强度、古河流水文参数显示出下岸角剖面地层沉积时，古环境演化大致经历了３个过程：早期（Ｑ２２）基底层沉积时，水流强度中等，河流规模小，年均径流总量小，气候偏干；中期（Ｑ３２）主体层沉积时，水流强度有波动，河流规模大，年均径流总量大，且间有湖泊和多层泥炭发育，气候湿润；晚期（Ｑ１３）盖层沉积时，气候变干，湿度复又变小．

The deposited environment of Xiaanjiao section at the southeastern foot of Lushan mountain was ascertained by distribution of grain and lithofacies.The main body of the section was the deposition of meandering river course,another were deposition of lakeside and detention basin.The water strength of deposition was ascertained by parameter of grain,the hydrology parameter of the river was counted by Summoon S A formula,those and parameter of grain all show the environment can be devided three stages.In the early stage(Q 2 2) and the late stage (Q 1 3),the river was small,the water strength was weak,the volume of runoff was less,those showed the humidity was lower than that of the middle stage(Q 3 2).