议京西大台地区的燕山运动

作者研究了京西大台地区的燕山运动，初步研究表明：这里不存在强烈的挤压变形迹象和显著的角度不整合．缺乏磨拉石建造。龙门组是厚度有限的河流相沉积，九龙山组是具有弱火山活动的湖相一滨湖相沉积。在隆起带和沉降带之间侏罗系地层显著的厚度变化率、大安山一斋堂滑覆构造及其派生的髫髻山断陷盆和大量高角度滑动面理，都显示了伸展构造背景下基底断块的差异升降。髫髻山组与壳幔相互作用有关的一套火山岩显示了上述运动的深部背景。

Discusion on Yanshanian movement in Datai area, west Beijing

The authors studied Yanshanian movement in Datai area, west Beijing. The preliminary study suggests that there seems not to be any indication of strong compressional deformation, prominent angular unconformity, or molasse formation in this area. Longmen formation is a river facies sediment with limited thickness, and Jiulongshan formation is a lake facies- littoral lake facies sediment with weak volcanic movement. The notable thickness gradient of the Jurassic stratigraphic between the upwelling and subsidence belts, the Daanshan-Zhaitang detachment structures, and the derivative Tiaojishan fault basin and high-angle bedding sliding, all indicate a differential upwarping and subsidence of the basement fault-block under the extensional background. A suit of volcanic rocks of Tiaojishan formation connected with crust-mantle interactions reveals the deep background of the above mentioned movements.