Bulletin of the Geological Society of Malaysia, Volume 33, Nov. 1993, pp. 143-152
Geological Research and Development Centre, Jalan Diponegoro 57, Bandung, Indonesia
Abstract: Physiographically southern Sumatra can be divided into four zones, from the west to east: Mentawai, Bengkulu, Bukit Barisan and Jambi-Palembang Zones trending northwest-southeast. These zones have been established as a result of subduction-related activities during Tertiary time.
The subduction regime that has occurred since the (middle) Paleogene, has been from the south-southwest and related activity has resulted in the different tectonic setting of each of the four zones.
The Mentawai Zone is a non-volcanic arc, occupied by an Oligocene-Miocene mélange complex and fine to coarse clastic accretionary prism sediments. The Bukit Barisan range is a continental margin volcanic arc which was formed by the subduction of the Indian-Australian Plate under the Eurasian Plate. The volcanic rocks of this range are characterised by andesitic to basaltic compositions typical of a calc-alkaline island arc setting.
Between the Mentawai Zone and Bukit Barisan Zone is the Bengkulu Zone which comprises turbiditic sequences of the fore-arc region. East of the Bukit Barisan Zone is the Jambi-Palembang Zone. This zone is characterised by transgressive and regressive sedimentary rocks deposited in back-arc basins. Both the Bengkulu and Jambi-Palembang Zones have hydrocarbon potential.