低角度断陷盆地成因模式及结构特征——以珠江口盆地恩平低角度断陷为例

作    者:何 勇1,2, 梅廉夫2, 施和生3, 舒 誉3, 陈 杨1
单    位:1 四川省煤田地质工程勘察设计研究院; 2 中国地质大学构造与油气资源教育部重点实验室 3 中国海洋石油(中国)有限公司深圳分公司
基金项目:受“十三五”国家科技重大专项“南海北部陆缘深部构造作用与新生代成盆演化耦合特征”等联合资助
摘    要:
目前地学界普遍认为低角度断陷盆地是由低角度正断层拆离形成的,具有上拆离裂离和上拆离斜坡两种成因模式。介绍、评论了5种低角度正断层成因模型。以珠江口盆地恩平低角度断陷为例,通过三维地震解释以及平衡剖面恢复,提出了一种新的模式——先存低角度逆断层负反转成因模式。认为不同成因的盆地具有不同的结构特征,低角度上拆离断陷盆地湖盆浅且无裂后沉积,低角度负反转断陷盆地湖盆深并且裂后沉积厚度大,前者往往不具备勘探价值,而后者的勘探潜力巨大。
关键词:断陷盆地;上拆离盆地;低角度正断层(LANF); 负反转模式; 恩平凹陷; 珠江口盆地

Structural characteristics and genetic model of the low-angle fault depression: a case in Enping Depression of Pearl River Mouth Basin

Author's Name: HE Yong, MEI Lianfu, SHI Hesheng, SHU Yu, CHEN Yang
Institution: —
Abstract:
Up to now, in the geological community, it is generally believed that the low-angle rift basin was formed by low-angle normal detachment fault, and it can be divided into two genetic models: supradetachment breakaway model and supradetachment ramp model. In this paper five kinds of genetic models of low-angle normal fault are introduced and reviewed. Taking Enping low?-angle fault depression of Pearl River Mouth Basin as an example, based on the 3D seismic profile interpretation and balanced cross-section restoration, this paper proposed a new model: negative reversion took place after the pre-existing low-angle reverse fault. It is shown that the different genetic basins have different structural characteristics. Low?-angle supradetachment basin with shallow lake experienced minor post-rift subsidence, while low-angle negative reversion fault basin with deep lake underwent prominent post-rift subsidence, and the former tend to have no exploration potential, but the latter has a huge exploration potential.
Keywords: graben basin; supradetachment basin; low-angle normal fault(LANF); negative inversion; Enping Depression; Pearl River Mouth Basin
投稿时间: 2018-01-02  
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