滇西兰坪盆地五茂林剖面下白垩统景星组沉积相

Sedimentary facies of the Jingxing Formation of Lower Cretaceous in Lanping Basin,West Yunnan

实测了云南西部兰坪盆地东部下白垩统下部景星组的五茂林剖面 ,建立了曲流河、三角洲和湖泊 3种沉积序列 ,其中三角洲序列在云南下白垩统中属首次建立。分析了粗碎屑岩的组成 ,将该剖面上出露的砾岩分成 4类。早白垩世时兰坪盆地属丹那沙林 -高黎贡弧的弧后盆地 ,景星组自下而上为曲流河沉积、三角洲沉积和湖泊沉积 ,且随湖侵发生 。

Based on a measured geological section at Wumaolin in the west part of Lanping Basin,western Yunnan,three sedimentary successions,namely,the meandering stream,deltaic and lacustrine successions,were established in the Jingxing Formation of the Lower Cretaceous,among which the deltaic one was firstly established in the Lower Cretaceous in Yunnan,and the herringbone cross bedding was firstly discovered According to the composition of coarse clastic rocks from the section,4 types of conglomerates could be classified During the Early Cretaceous,the central western Yunnan area belonged to a continental backarc basin of the Tenasserim Gaoligong Arc The Jingxing Formation consisted of,from west to east,the braided river,meandering stream,deltaic and lacustrine deposits,with the lacustrine basin enlarged westwards