Oligocene-Miocene drainage evolution of NW Borneo: Stratigraphy, sedimentology and provenance of Tatau-Nyalau province sediments

•Tatau-Nyalau province is sourced predominantly by the Sunda River system.•Sediments of the Sunda River are dominated by Permo-Triassic & Precambrian zircons.•Proto-Rajang sediments are characterised by a higher amount of Cretaceous zircons.•Source areas are East Malaya for the Sunda River and Borneo for the proto-Rajang.•Nyalau Unconformity marks a change in sediment provenance and coastline orientation.