Michael Cottom

The Meratus Mountains occupy an extremely interesting, and potentially critical, position in terms of understanding the geological evolution of the surrounding region.  Bordering both the Makassar Straits – an area still poorly understood – and the large Cenozoic basins of SE Kalimantan, the mountains may offer insight in to the geological evolution of both these environments.

Geologically, the Meratus Mountains comprise a complex association of high-pressure metamorphic rocks, variously serpentinised ultramafic rocks, melanges and clastic and carbonate sediments that are the products of a Cretaceous oceanic arc obducted onto the Sundaland margin in the Late Cretaceous.

The Meratus are one of several such subduction complexes that are alleged to surround the southeastern margin of Sundaland in Indonesia.  Obduction resulted in strong structural grain throughout the Meratus, dominated by NE-SW trends.  The Mesozoic arc rocks, and contemporaneous intrusives and arc associated lithologies, are in turn unconformably overlain by the Cenzoic formations that are presently found within the Barito and Asem-Asem basins, flanking the NW and SE sides of the mountains respectively.

meratuscoalpit

Spectacular outcrop of Cenozoic sediments in the Asem-Asem Basin near Kintap

Grantitic rocks intruding arc related lithologies in the northern Meratus.

Grantitic rocks intruding arc related lithologies in the northern Meratus.

This project aims to investigate the timing and rate of exhumation of the Meratus Mountains. This will be acheived through application of thermochronology to the granitic rocks that, although rare, intrude the Meratus in the north of the region.