Geology of the central Sulawesi belt (eastern Indonesia): constraints for geodynamic models

Abstract

Sulawesi island, located at the junction of the Asian, Australian and Pacific plates, is geologically important for unraveling the Cenozoic tectonics of South-East Asia. This island, situated on the active margin of the Asian plate suffered at least four major tectonic events in Mid-Cretaceous, Oligo-Miocene, Middle Miocene, and Early Pliocene times. The present paper is focused on the Oligo-Miocene event, which formed the main orogenic belt of this island. Several geodynamic models have been proposed for this belt. Our structural and stratigraphic investigations in the central area of Sulawesi lead us to favor an eastward obduction of an ophiolitic nappe of Asian origin onto a continental Gondwana Block, while a west-dipping slab was subducting underneath the western Asiatic margin. Collision between this fragment of Gondwana and the active Asiatic margin in Late Oligocene or Early Miocene time produced the central metamorphic belt of Sulawesi.