Publications

The Barito and Asem-Asem Basins occupy the south-eastern corner of Borneo, and are separated by the Meratus Mountains – an accretionary collision complex that records the suturing of East Java-West Sulawesi to Sundaland in the mid-Cretaceous. The basins contain comparable sedimentary successions of Middle Eocene to Pleistocene age, that suggest they once formed a much larger depocentre prior to the uplift of the Meratus in the Neogene. The uplift had a profound effect on the basin architecture, developing a foredeep along the west side of the emerging mountain front, and creating the present-day hydrocarbon plays of the Barito Basin. Thus, understanding the history of the Meratus uplift not only provides insight into the tectonic evolution of the basins, but also the development of the hydrocarbon system. We present a combination of structural, sedimentological, provenance and satellite data that collectively indicate a piecemeal uplift history of the Meratus. Sedimentology, palaeocurrents and zircon geochronology from sandstones of the Montalat Formation strongly suggest that uplift of the northern part of the Meratus initiated during the Early Miocene – considerably earlier than previously thought. In contrast, reversal of palaeocurrents recorded in the upper part of the Warukin Formation indicates that uplift further south did not occur until the Late Miocene. We suggest this diachronous uplift history was facilitated by a pre-existing NW-trending basement fabric visible from gravity data in the Barito Basin and from NW- trending lineaments that dissect the Meratus.