断陷湖盆的沉积层序特征——以辽河盆地东部凹陷为例

THE SEQUENCE CHARACTERISTICS OF RIFT LAKE BASIN -EASTERN DEPRESSION,LIAOHE BASIN AS A EXAMPLE

通过对辽河盆地东部凹陷沙河街组－东营组沉积层序的研究得出，构造沉降是断陷湖盆层序的最主要控因。构造沉降级次控制着层序的级别，一次完整的继承性沉降形成一个Ｉ级层序，整体显示由细变粗的水退旋回；该沉降期内部又以沉降平静期为界分为三个沉降阶段，分别形成三个ＩＩ级层序，各层序都在一定程度上呈粗－细－粗的水进水退旋回；构造沉降的特点影响沉积层序的完整性；通过影响盆地的补偿性质，构造沉降速率控制着沉积相的类型及演化。

Tectonic subsidence is the main controlling factor of rift lake sequence.Based on the research on the sequences of Sahejie-Dongying Formations in eastern depression,Liaohe basin,it is concluded that tectonic subsidence affects the characteristics of sequence in several ways.The scale of subsidence controls the order of sequence.A whole succeeding tectonic subsidence forms a sequence of 2nd order,which shows a overall coarse-fine and water deepening circle.This whole period is subdevided into three subsidence stages by relatively peaceful subsidence periods,which form three sequences of order III respectively,each of them showing coarse fine coarse and deep shallow deep water depth circle.The characteristics of tectonic subsidence also control the perfection of sequences.By affecting the compentation quality of the basin,tectonic subsidence controls the type and evolution of sedimentary facies.