Jurassic-Cretaceous palaeogeography of the Jagoi-Serikin area as indicated by the Bau Limestone Formation

Abstract

A reef complex with minor patch reef and mud-mound model is postulated for the Late Jurassic-Early Cretaceous Bau Limestone in the Jagoi-Serikin area. Mudstone, wackestone and packstone representing the back reef area are mostly distributed in close proximity to the landmass, composed of Jagoi Granodiorite. Stromatoporoid-coral-algal boundstone representing ecologic reef with minor packstone, is mainly distributed in the centre of the embayment and farther out on the slope of the basin. The Jurassic-Cretaceous palaeogeography of the area is modelled as the margin of a landmass, where Gunung Jagoi and Gunung Kisam formed two promontaries bordered by a fringing reef complex on the slope of a rapidly subsiding basin in which the Pedawan Formation was deposited.