New Insights on the Structural Configuration and Tectonic Evolution of the Malay Basin

This study revisits the tectonic evolution of the Cenozoic section in the Malay Basin, leveraging a comprehensive 3-D seismic database to conduct a detailed structural analysis. It identifies four primary litho-tectonic units:

1. Oligocene Syn-Rift Unit 1: Characterized by east-west extensional tectonic fabric and associated normal faults and asymmetric half-grabens. This unit marks the basin’s opening phase of an oblique continental rifting.
2. Early to Late Miocene Post-Rift Unit 1: This period is defined by thermal subsidence and dextral wrench faulting, influencing the creation of accommodation spaces in the basin.
3. Upper Miocene Post-Rift Unit 2: Marking a peak in compressional tectonics, this phase sees the reactivation of east-west trending normal faults, leading to the formation of inversion anticlines and inverted half-grabens.
4. Pliocene to Recent Post-Rift Section 3: This latest phase is characterized by high tectonic subsidence and transtensional movements along the northern part of the basin. Notable for its north-south tectonic fabric, it features high-angle normal faults indicating a significant shift in the basin’s tectonic regime.

Overall, the study underscores a continuous tectonic influence from the lower Miocene to the present, linked to the collision of the Sunda SE Asia margin with the northwest subducting Indian-Australian plate.