Structural Evolution of the Songkhla Basin, Gulf of Thailand: A Palinspastic Restoration Study

Abstract

The structure styles of Songkhla Basin are not well known as compared to other Cenozoic basins of the Gulf of Thailand. This study describes the results of 2D and 3D seismic data interpretation and restoration of key sections. Inversion occurred as local phenomena along eastern and western margin of the basin. The timing of initiation and cessation of the inversion is different in different parts of the basin. Onlap on anticlinal feature indicates that along the western margin in the center of the basin inversion ceased by Late Oligocene. While, in relatively southern part it ended in Middle Oligocene. Palinspastic restoration shows that rifting initiated along N-S oriented faults in the Eocene?, characterized by the thick syn-rift package in the western part of the basin. It also observed that along the eastern margin inversion started in Early Oligocene in northern sections while relatively southern sections show initiation of inverted features in Late Oligocene. This local inversion along the eastern margin lasted until Early Miocene. Coherency and phase slices show NW-SE discontinuity, which at some places cut cross the regional N-S faults. These are also associated with compressional features as observed on arbitrary perpendicular seismic sections. These discontinuities are interpreted as faults influenced by pre-rift fabric. Possible hydrocarbon traps are titled fault blocks, faulted anticlines and rollover close to boundary faults