摘要
边界断裂控制断陷盆地的形成和构造格局,不同边界断裂联接模式对不同类型盆地演化具有差异性.基于井控高精度3D地震资料,通过对边界断裂几何学特征描述和"四级小层"刻画,结合裂陷I幕边界断裂不同区段的活动差异性以及与沉积中心迁移的空间匹配关系,剖析珠江口盆地惠州凹陷北部边界断裂的形成和演化.惠州凹陷北部边界断裂始新世早期分段孤立发育,逐渐以纵向和横向双向联接的模式发展.纵向联接为断层软联接和硬联接复合联接和转换,形成转换斜坡和横向背斜,控制凹(洼)陷的结构与演化,制约沉积中心及层序的迁移.横向联接表现为转换斜坡内横向断层的多阶段联接,联接过程可划分为孤立正断层、同向叠置及硬联接3个阶段,控制转换斜坡带内沉积体系的发育和展布.研究给出了一个裂陷盆地边界断裂时空演化、复合联接和转换模式的独特案例,对丰富裂陷盆地边界断裂及其与沉积层序、凹陷演化和区域动力学机制的响应关系的研究具有积极的意义和价值.
The formation and tectonic framework of a faulted basin are controlled by boundary fault,which have different types of basin evolution under different boundary connection modes.The purpose of this study is to recognize the linkage model of boundary faults of northern Huizhou sag in Zhu I depression,Pearl River Mouth basin（PRMB）,the South China Sea,which is a representative of global passive continental margin basins.Based on well controlling high-precision 3 Dseismic survey,the geometry of boundary faults and the framework of＂four-order sequences＂are determined in PRMB.The fault activities of different boundary fault sections and the spatial change of depocenters during rift episode I are analyzed.An evolution model of boundary fault system in northern Huizhou sag,PRMB is established in this study.The results show that the northern bounding faults of northern Huizhou sag have an offset geometry in Early Eocene,characterized by along-strike and transverse twoway linkage.The along-strike linkage is a composite connection-transformation of＂soft and hard＂linkage,forming a relay ramp and transverse folds which restrict the structural evolution within Huizhou sag and the migration of its depocenters and sequences.The transverse linkage means the multiple-stage linkage of the transfer faults in relay ramp,including three stages,namely,isolated normal faulting,synthetic overlapping and hard linkage,which control the migration and distribution of depositional system within the relay ramp.This paper presents a unique case of spatial evolution,complex linkage and transformation model of boundary faults in a rift basin,which can facilitate further studies on the response relationship among the bounda-ry fault,sedimentary sequence,sag evolution and regional dynamics mechanism.
出处
《地球科学（中国地质大学学报）》
EI
CSCD
北大核心
2015年第12期2037-2051,共15页
Earth Science-Journal of China University of Geosciences
基金
国家科技重大专项课题子课题(No.2011ZX05023-001-015)
关键词
断裂联接
断裂转换
边界断裂
惠州凹陷
珠江口盆地
构造
fault linkage
fault transformation
boundary fault
Huizhou sag
Pearl River Mouth basin
tectonics
