北京西山白垩纪岩石地层划分

LITHOSTRATIGRAPHIC DIVISION OF THE CRETACEOUS IN THE TUOLI-DAHUICHANG AREA,WESTERN HILLS,BEIJING

摘要: 笔者在北京西山坨里一大灰厂一套白垩纪地层进行１：５万区调时，发现原辛庄组与芦尚坟组下部的紫色岩层是出露于不同构造部位的同一层位；原辛庄组建组剖面顶底不全。因此，本文废弃辛庄组，解体芦尚坟组，将这套地层由底至顶划分为东狼沟组、大灰厂组、坨里组、夏庄组。

Abstract: In this paper,the Cretaceous in the Tuoli-Dahuichang area,Western Hills, Beijing,is lithos-tratigraphically divided in ascending order into the Donglanggou Formation,Dahuichang Forma-tion,Tuoli Formation and Xiazhuang Formation,It expounds the theory and grounds for rejectingthe Xinzhuang Formation and disintegrating the Lushangfen Formation。Besides,it is confirmedthat the Donglanggou Formation is represented by an association of pyroclastic rocks,sedimentaryrocks and basalt.The isotope ages of 105. 3±2.71Ma and 100.14±2.35 Ma were obtained for thefirst time.