Madon, Mazlan and Amir Hassan, Meor Hakif and Jong, John (2022) An erosional unconformity at the top of the Nyalau Formation near Bintulu, Central Sarawak (Malaysia): Its regional context and significance. Bulletin of the Geological Society of Malaysia, 73. 35 – 52. ISSN 0126-6187, DOI https://doi.org/10.7186/bgsm73202204.
Full text not available from this repository.Abstract
This article documents an erosional unconformity at the top of the Nyalau Formation (Oligocene-Early Miocene) exposed in a road-cut northeast of Bintulu in central Sarawak. The outcrop succession essentially comprises a lower unit of thickly-bedded sandstones representing wave-dominated shoreface facies overlain by fluvio-tidal channel deposits that were deposited following a base-level lowering. This gently tilting sand-rich unit is cut by an irregular concave-up erosional surface, overlain by mudstones and thinly interbedded heterolithics that show large-scale internal stratification indicative of multiple scour-and-fill structures, progradation and/or lateral accretion. The erosional surface separating the two units not only marks a significant shift in sedimentary facies but the fact that it cuts into deformed and tilted strata (Upper Nyalau) suggests that it is an erosional unconformity caused by a tectonic deformational event. Based on regional structural synthesis and stratigraphic evidences, the unconformity probably represents the eroded top of the Nyalau Formation, overlain by a relatively undeformed succession tentatively correlated with the Early-Middle Miocene post-Nyalau formations in the Mukah-Balingian region. © 2022 by the Author(s).
| Item Type: | Article |
|---|---|
| Funders: | None |
| Additional Information: | Cited by: 2; All Open Access, Gold Open Access |
| Uncontrolled Keywords: | Erosional surface; Facies; Nyalau Formation; Sarawak Cycles; Unconformity |
| Subjects: | Q Science > QE Geology |
| Divisions: | Faculty of Science > Department of Geology |
| Depositing User: | Ms. Juhaida Abd Rahim |
| Date Deposited: | 30 Nov 2023 02:22 |
| Last Modified: | 01 Dec 2023 08:59 |
| URI: | http://eprints.um.edu.my/id/eprint/43761 |
Actions (login required)
 |
View Item |
