Structural style and tectonics of Western and Northern Sabah

Abstract

The Western and Northern part of Sa bah, consisting of sedimentary and igneous rocks of Early Cretaceous to Pliocene in age, has undergone several episodes of deformation, the earliest episode of deformation which was responsible for the deformation and uplift of the basement rock (chert-spilite formation), probably occurred during Late Cretaceous to Early Eocene time. This early deformation is thought to have controlled the development of an elongate basin trending approximately N-S and E-W in Western and Northern Sabah respectively which later became the site for the deposition of Middle Eocene to Early Miocene sediments of the Crocker, Trusmadi and Kudat Formations. These sediments were subsequently deformed by NW-SE and N-S compressive directions in Western and Northern Sabah respectively during Middle Miocene times to form a series of imbricate thrust slices. Chaotic deposits developed along major fault zones. The NW-SE and N-S compressive directions controlled the development ofNE-SW and E-W trending basins in Western and Northern Sabah respectively for the deposition of younger sedi­ ments during Upper Miocene to Pliocene times. The continued NW-SE and N-S compres­ sion gently deformed these sediments.