四川大邑-汶川地区侏罗-第三系砾岩特征及沉积环境

龙门山中南段四川大邑、崇州、都江堰、汶川地区，侏罗系、白垩系、第三系发育良好，划分为侏罗系白田坝组、千佛岩组、沙溪庙组、遂宁组、莲花口组及五龙沟砾岩一组至三组；白垩系天马山组、夹关组和灌口组；下第三系名山组和上第三系（上部包括部分第四系）的大邑砾岩等岩石地层单元。各个地层单元中几乎都有砾岩沉积。概述了该区砾岩的时空分布及特征，按沉积环境将砾岩划分为冲积扇砾岩、河道滞留砾岩及湖滨砾岩等，最后讨论了物源区及其时空演化。

Characteristics of Jurassic-Jertiary conglomerates and depositional environment in the Dayi-Wenchuan area,Sichuan

The Jurassic， Cretaceous and Tertiary are well developed in Dayi， Chongzhou， Dujiangyan and Wenchuan， Sichuan， in the central and south segments of the Longmen Mountains． Its lithostratigraphic units include the Baitianba Formation， Qianfoyan Formation， Shaximiao Formation， Suining Formation， Lianhuakou Formation and Wulonggou conglomerate of the Jurassic， the Tianmashan Formation， Jiaguan Formation， and Guankou Formation of the Cretaceous， the Mingshan Formation of the Paleogene and the Dayi conglomerate of the Neogene （part of the upper part of the conglomerate is Quaternary in age）． Nearly all the lithostratigraphic units contain conglomerate． This paper outlines the temporal-spatial distribution and characteristics of conglomerates in this area． On the basis of the depositional environment the conglomerates are divided into alluvial fan conglomerate， channel lag conglomerate and lakeshore conglomerate． Finally， the source regions and their time-space evolution are discussed．