Bulletin of the Geological Society of Malaysia, Volume 35, July 1994, pp. 97-112
Department of Geology, University of Malaya, 59100 Kuala Lumpur
Abstract: The sedimentology and deformation of the Temburong Formation in East Brunei are described. Original sedimentary structures are still preserved, particularly in the arenaceous sediments and paleo-environmental indicators suggest deposition mostly in a shallow water, subsaline embayment or lower alluvial floodplain environment. The style of deformation varies according to lithology and bed thickness and the rocks are metamorphosed to sericite grade. Deformation is thought to have been caused by loading rather than tectonic compression. The timing of the deformation took place probably between the Te1-4 and Te6 Indonesian Letter Stages, i.e. upper Oligocene to Lower Miocene. No basal conglomerate has been found between the Temburong Formation and the overlying Setap Shale Formation and there is unlikely to be an unconformity separating the two formations although a hiatus between Te1-4 and Te6 has been recognised in major platform carbonate sequences in the Melinau Limestone Formation at Melinau, Batu Gading and Keramit as well as the turbiditic limestone at Selidong. The regional distribution of the Temburong Formation is discussed in relation to the paleogeography of NW Borneo.