Geology and origin of the Southeast Sulawesi continental terrane, Indonesia

ABSTRACT The Southeast Sulawesi Continental Terrane, which is now located in the Southeast Arm of Sulawesi, Eastern Indonesia, is separated from the Eastern Sulawesi Ophiolit Belt by the Lawanopo Fault in the northeast and by the Kolaka Fault in the southwest. Its contacts with the ophiolite belt in the west and east are also faults. The oldest exposed unit within the Southeast Sulawesi Terrane is the pre-Carboniferous low-grade metamorphic rocks. It is intruded by Permo-triassic aplite and its associated volcanics/lavas. The units are unconformably overlain by the Triassic clastic sediments of the Meluhu Formation. The formation is unconformably overlain by Paleogene carbonates of the Tamborasi and Tampakura Formations. Based on the similarities in stratigraphy and sedimentological history, the Southeast Sulawesi is thought that has a same origin as the Banggai-Sula continental terrane. Both terranes were probably derived from the northern margin of the Australian Continent. Before the terranes collided with the Eastern Sulawesi Ophiolite Belt in the latest Oligocene, they were joined together as the Great Banggai-Sula Terrane. Three major tectonic events occurred before the collision: the Permian-Late Triassic pre-rift (pre-breakup), Jurassic breakup and Late Jurassic-Oligocene rift-drift