北大港潜山在沙三段沉积期的隆升状态及其对沉积物源的供给

Uplift and Erosion of the Beidagang Buried-hill During the Deposition of the Third Member of the Shahejie Formation

北大港潜山构造带的高点区无沙三段沉积,依照地层终止方式无法厘定出北大港潜山的高点区是在沙三段沉积期一直暴露地表没有接受沉积,还是在沙三段沉积期接受了沉积,后被晚期构造抬升剥蚀殆尽。确定北大港潜山高点区在沙三段沉积期的演化状态对于分析本区沉积体系及储层分布至关重要。本文以构造与沉积的响应关系为分析的思路和依据,通过地层厚度图的框架约束,基于砾岩分布和泥岩颜色所指示的古环境、古地貌、古物源的特征,分析出北大港潜山高点区在沙三段沉积期一直是一个稳定的物源区,其剥蚀下来的物源通过构造转换带的控制,沉积在板桥凹陷和岐口凹陷。

The lack of the third member of the Shahejie Formation on the top of the Beidagang buried-hill might arise either from having not received sediment during the Es3 or denudation caused by the later structural uplift.However,the evolution of the Beidagang buried-hill during the Es3 is critical for depositional system and reservoir analyses.So the evolution of the Beidagang buried-hill is analyzed on the basis of the sequence thickness,mudstone color and conglomerate distribution.Two conclusions were drawn：1） the top area of the Beidagang duriedhill received no sediment during the Es3;on the contrary,2） the denudation of the Beidagang buried-hill during the Es3 served part of the provenance of the Banqiao and Qikou sags via the transfer zone.