Provenance and Age of Mesozoic to Cenozoic Sedimentary Successions and Tectonic History of West and Central Sarawak

Abstract

Summary Sarawak is located on the northern edge of Sundaland in NW Borneo. West and Central Sarawak include parts of the Kuching and Sibu Zones. These contain remnants of several sedimentary basins with ages from Triassic to Cenozoic. New light mineral, heavy mineral and U-Pb detrital zircon ages show differences in provenance reflecting the tectonic evolution of the region. This project presents new Ar-Ar ages from metamorphic rocks in West Sarawak that require a revision of tectonic models, as well as new U-Pb zircon ages, light and heavy mineral compositions of sedimentary rocks in West and Central Sarawak. A revised stratigraphy has been developed in this study. The sedimentary successions in are dated as Triassic to Cenozoic in West Sarawak and Late Cretaceous to Cenozoic in Central Sarawak Our data show that the area of the Kuching (West Sarawak) and Sibu (Central Sarawak) Zones were connected with SW Borneo and Sundaland from the Cretaceous onwards. The Cretaceous and Cenozoic sedimentary basins were sourced by alternations of Schwaner Mountains and Malay Tin Belt rocks and contemporaneous volcanic activity.