辽河滩海西部沙三段层序界面构型及层序地层特征

INTERFACE PATTERN AND SEQUENCE STRATIGRAPHIC FEATURES OF ES3 MEMBER IN WESTERN LIAOHE BEACH

通过钻测井、地震等资料,将辽河滩海西部地区沙三段划分为2个三级层序,并深入研究了层序界面不整合构型及分布特征。层序界面整体表现出明显的纵向继承性与横向分带性,洼陷区持续接受沉积,地层接触关系以整合为主;斜坡区发育多级次坡折带,各时期地层超覆其上,形成超覆不整合;上斜坡区地层遭受剥蚀,为上超下削型不整合区。纵向上,不同盆地演化阶段湖盆范围发生变化,相对沙三底,沙二底整合区的范围相对向西扩大,反映该时期湖盆扩张,水体范围增大。滩海西部地区沙三段层序发育总体具有北厚南薄、中间厚两侧薄的特征。西部斜坡带层序发育齐全,但厚度相对较薄,层序结构清晰,东部海南洼陷带层序厚度大,沉积了一套湖相细粒沉积。

This paper, based on logging and seismic data, divides Es3 Member, western Liaohe beach, into two third- order sequences, and studies the stratigraphic interface unconformity and distribution, which displays a vertical succession and lateral zonation. Depressions receive continuous sedimentation with conformity contact. Slopes develop truncations overlapping the previous ones with an unconformity. The upper slope had been eroded, forming an aboveoverlapping-below-truncation unconformity. Vertically, basin ranges with times. Es2 bottom, compared to Es3 bottom, expands to the west with an increasing water area. Generally, Es3 Member is thick in the north and thin in the south, and thick in the center. The west slope is well developed in stratigraphic sequences, thin, with clear structure; the east Hainan sag is thick with fine lacustrine sediment.