北部湾盆地北部坳陷古近纪原型结构分析

北部湾盆地北部坳陷古近纪受多期次构造运动的影响,后期改造强烈.从现今构造格局出发,通过剥蚀量恢复并结合断裂活动特征,进行了北部湾盆地北部坳陷古近纪原型结构重建及成凹机制探讨.认为北部湾盆地北部坳陷古近系沉积沉降中心在时空上呈现由西向东和由北向南的迁移特征;始新世流沙港组沉积时期涠西南凹陷D次凹与海中凹陷的西洼为同一沉积单元;断裂和隆起联合控制了洼陷的基本形态,特别是涠西南低凸起的活动对北部坳陷古近纪统一湖盆的分割起关键作用.

Analysis of Paleogene Prototype Basin in Northern Depression of Beibuwan Basin

The Northern Depression of Beibuwan basin experienced multi-stage tectonic movement in paleogene, resulting in strong basin reformation. From the present tectonic framework, by denudation restoration, together with analysis of the characteristics of fault activities, prototype structure reconstruction has been conducted and basin formation mechanisms in paleogene in the northern depression of Beibuwan basin are discussed in this paper. It is believed that the subsidence and depocenters of Northern Depression shifted from west to east and from north to south. In Middle Eocene during deposition period of Liushagang formation, Weixinan D sag and Haizhong west depression were the same sedimentary unit. Faulting and uplifting controlled the basic shape of depressions, especially the uplifting activity of Weixinan low in Northern Depression, which play a key role for partition of unified lake basin in paleogene.