辽河盆地西部凹陷沙河街组西八千扇体

利用丰富的钻井、测井、地震等资料，以层序地层学理论为指导，将辽河断陷西部凹陷发育的老第三系沙河街组划分为3个层序7个体系域，并以体系域为单元描述西八千扇体的沉积体系类型、沉积作用特点、空间分布及其演化。在不同层序发育过程中，各因素所起的作用有主次之分。沉积速率和构造沉降是湖泊水深变化的主要控制因素；构造因素对层序Ⅱ的旋回性和特殊的沉积充填样式等起主导作用；在构造作用相对平稳的层序Ⅲ发育时期，气候因素的影响通过多个准层序叠加及湖平面频繁变化表现出来。

SEDIMENTARY CHARACTERISTICS AND CONTROLLING FACTORS OF XIBAQIAN FAN OF SHAHEJIE FORMATION, WEST DEPRESSION, LIAOHE BASIN

Based on the data of drilling, well logging and seismics, 3 sequences and 7 system tracts in the Xibagian fan of the Palaeogene Shahejie Formation in the West Depression of Liaohe Basin are recognized by the sequence stratigraphy theory. The sedimentary systems, sedimentation, spatial distribution and evolution of each tract are described in detail. It is indicated that some of the controlling factors are more important than others in the process of the development of different sequences. The lake level change was mainly controlled by the depositional rate and tectonic subsidence. The cycles and depositional characteristics of the sequence II were chiefly caused by tectonics. During the period of the sequence III development, the tectonic movement was relatively stable, and the influence of climate was presented through the stacking pattern of parasequence and frequent lake level change.