Transcurrent faulting in the Sarawak-Kiri region, Sarawak, East Malaysia

Abstract

Summary Geological discontinuities, lineaments, field observations, and interpreted π-girdles demonstrate a left lateral, NNW trending transcurrent fault in the Sarawak-kiri valley of West Sarawak. Topography and geology also suggest that the fault belongs to an important fracture zone that extends well into Indonesian Kalimantan, and continues in a northerly direction along the edge of the Sunda Shelf beneath the South China Sea. Comparison with transcurrent faulting occuring in the Malay Peninsula and a probable wrench fault between Palawan island and Sabah (North Borneo) reveals the continental part of southeast Asia to have rotated counter-clockwise up to Lower Palaeogene time, probably as a response to spreading of the Pacific ocean floor.