塔南凹陷白垩纪古地貌对沉积体系分布的控制作用

塔南凹陷是在海拉尔-塔木查格盆地新发现的主要油气勘探和开发区。对早白垩世沉积充填特征的综合研究表明,长期活动的同沉积断裂形成的、古地貌上突变的各种断裂坡折带对盆内沉积体系的发育及分布起到重要的控制作用。根据塔南凹陷边缘和盆内的古地貌结构特征,将其划分为断崖型陡坡坡折带、断阶型陡坡坡折带、断阶型缓坡坡折带和盆内坡折带4种类型,它们各自控制了不同类型沉积体系的形成和分布。断崖型陡坡坡折带控制着近岸水下扇沉积体系的形成和分布;断阶型陡坡坡折带控制着扇三角洲或近岸水下扇及前方的湖底扇体系的形成和分布;断阶型缓坡坡折带控制着扇三角洲沉积体系的形成和分布;在基准面下降阶段,盆内坡折控制着远岸湖底扇的形成和分布。

Controlling of paleo geomorphology to distribution of sedimentary system in the Cretaceous of Tanan Depression

Tanan Depression is a newly found area for petroleum exploration and development in Hailar-Tamuchage Basin. The comprehensive study on the sedimentary features in the early Cretaceous of Tanan Depression showed that the different kind of fault slope belts resulted from syn-sedimentary tectonic movement in the paleo geomorphology controlled the formation and distribution of sedimentary system. According to the configuration of paleo geomorphology in the margin and inner part of Tanan Depression, the paleo slope break belts developed in the Cretaceous of Tanan Depression were divided into four types. Every type controlled the formation and distribution of the different sedimentary system. The faulted scarp type slope break belt controlled the development of the near shore sub-aqueous fan system. The faulted terrace type steep slope break belt controlled the development of the fan-deltas and sub-aqueous fan system. The gentle slope type slope break belt controlled the development of the fan delta system. The inner basin type slope break belt controlled the off shore sub-lacustrine fan system in the basin-level falling stage.