四川龙门山中段上三叠统须家河组特征

上三叠统须家河组广泛分布于四川汶川县、都江堰市、崇州市、大邑县等毗邻地区，呈NE向展布，出露面积大于150km^2，厚度大于2851m。笔者在进行1：5万“三江幅”和“万家坪幅”区域地质调查时，于该区测制了须家河组剖面。本文对这一地区的须家河组进行了一、二、三段的划分，并对岩石特征、地层对比、底顶界线、生物地层和年代地层者概略讨论；须家河组的沉积环境可划分为三角洲相和河流相。

The Upper Triassic Xujiahe Formation in the Longmen Mountain area, Sichuan

The N-S-elongated Upper Triassic Xujiahe Formation strata cover an area of 150 km2 and a thickness of more than 2851 m in the Dayi-Chongzhou-Dujiangyan-Wenchuan zone, Sichuan. After the surveying of the 1∶50000 Sanjiang Sheet and Wanjiaping Sheet from 1997 to 1999, the author subdivided the Formation into three members, with particular emphasis on lithology, stratigraphic boundary and correlation, biostratigraphy and chronostratigraphy. Two types of sedimentary environmerts are also discriminated:delta facies and fluvial facies.