东营凹陷西部红层沉积期沉积体系及物源方向研究

Sedimentary System and Provenance Orientation of the Red-Bed Sedimentary Period in Dongying Sag

在对地质资料、地震资料及地球化学资料详细解剖的基础上,以东营凹陷西部红层沉积期构造演化阶段的划分及古地貌的恢复为切入点,通过对物源、沉积体系的系统研究,明确了东营凹陷西部红层沉积期物源方向及沉积体系的时空演化特征。研究认为:东营凹陷西部红层沉积期可以划分为孔一段时期和沙四下亚段时期两个构造演化阶段;红层沉积前盆地整体呈现四面环凸、西高东低、西部地形整体较为平缓的古地貌格局,古地貌的时空差异影响并控制了东营凹陷西部红层层系的沉积。东营凹陷西部红层沉积期存在西北无棣—滨县凸起和南部鲁西隆起两大远物源体系和平南断层上升盘近物源体系,红层沉积后期,平南断层上升盘近物源体系消失。东营凹陷西部红层沉积期主要发育了冲积扇、辫状河、湖泊及滩坝等沉积体系,盆地北部还发育了近岸水下扇沉积体系;古地貌、古物源及古气候的变迁使得沉积体系的时空展布表现出继承性与差异性并存的特征。

Based on the detailed analysis of geological data, seismic data and geochemical data, through the method of the dividing of structure evolution stages and recovery of palaeogeomorphic, combined with prove-nance sedimentary system, the paper studied the temporal and spatial evolution features of sedimentary system and provenance orientation in the red-bed sedimentary period in the western area of Dongying Sag. The period in the western area of Dongying Sag was divided into the 1 st of Kongdian Formation and the lower part of the 4th member of Shahejie Formation. Before deposition of the 1 st member of Kongdian Formation, the Luxi uplift, Guangrao bump, Chenjiazhuang bump, Binxian bump and Wudi bump were formed. The main faults are Chen- nan Fault, Binnan Fault, Yangxin Fault, Shicun Fault and Gaoqing-Pingnan Fault and so on. The whole basin presents the palaeogeomorphic of bumps around, east low, and west high and flat terrain in the west. The prove- nance of the western area of Dongying Sag in the early stage of Kongdian-Shasi is mainly from the northwest and the south orientations. There are two further provenance systems of Wudi to Binxian bump, Luxi uplift, arid one provenance system of Pingnan Fault. There are sedimentary systems such as alluvial fan-braided river-lake sys- tem, alluvial fan-alluvial plain-lake system, lake-beach bar and subaqueous fan-lake system. The changes of palaeogeomorphic, provenance and ancient climate influence the temporal and spatial evolution of the sedimen-tary system with the characteristics of inheritance and difference.