Abstract: Subsidence Modeling of the Sabah Basin, a Foreland Basin, Northwest Borneo, Malaysia
Noor Azim-Ibrahim, Nicky White
The Sabah Basin is located on the northwestern side of Borneo. It is a piggy back northeast-southwest-trending basin, riding on a north-westward directed imbricate thrust system. The basin contains approximately 10 to 12 km of sediment in the deepest part deposited in two main episodes of basin development: (1) a pre-early middle Miocene phase of generally deep-marine clastic deformation, which was later subjected to compression and (2) a post-early middle Miocene episode of clastic deposition, comprising bathyal to upper coastal plain sediments. Tectonic subsidence of the post-middle Miocene sequence was determined using the 1-D Airy and 2-D flexure backstripping techniques on wells and selected dip profiles, where the effects of compaction and sediment loading were removed. Variatio in paleowater depth was also taken into account. The results show an extremely rapid subsidence phase dominating the earlier part of the basin history, with the later part corresponding to passive basin infilling. The boundary between these two phases becomes younger toward the northwest. The rapid subsidence phase is attributed to tectonic loading, possibly as a result of continuing thrusting at the basin margin. The results also imply that sedimentary sequences formed during the earlier phase were tectonically controlled and marked by transgressive events, while those deposited during the later phase bear the imprints of both tectonic and eustasy.
AAPG Search and Discovery Article #90982©1994 AAPG International Conference and Exhibition, Kuala Lumpur, Malaysia, August 21-24, 1994