Publications

The Bone Basin, located between the south and southeast arms of Sulawesi, is interpreted to be a composite basin, with its origin as a subduction complex and suture between Sundaland and Gondwana-derived micro-continents. It subsequently evolved as a submerged intra-montane basin.Tectonic and stratigraphic evolution of the Bone Basin is still poorly understood due to limited data. A new model based on integration of speculative seismic data, published surface geology maps, and well data is presented for the tectonic and stratigraphic evolution of the Bone Basin. The basin had two major periods of development: (a) Paleogene to Early Miocene, and (b) Early Miocene to Recent. Originally, the basin probably occupied a forearc setting as part of a westward subduction complex during the Paleogene to Early Miocene. Subsequently, westerly plate convergence of Australian-derived micro-continents toward the subduction complex during the Middle to Late Miocene, dramatically changed the style of deposition, structural framework, and configuration of the basin. A Middle Miocene collision of the microcontinents with the subduction-related accretionary complex, followed by collision of the microcontinents with West Sulawesi, built orogens surrounding the Bone Basin which shed large volumes of sediment into the northern depocenter of the Bone Basin. The collision led to an eastward rotation of Southeast Sulawesi, which resulted in rifting and submergence of the southern part of the basin. Compression from the collision propagated a major back-thrust system westward to the subduction zone, generating fold belts, as indicated by the westverging Kalosi and Majene fold belts in West Sulawesi.The two colliding plates began to lock during the Pliocene, and the continued plate convergence was accommodated by strike-slip movements along the Walanae, Palukoro and many other faults. Subsequently the Bone Basin submerged into an intra-montane basin setting. Clastic sediments derived from surrounding mountains to the east, north and west were deposited progradationally southward toward the depocenter of the basin. Strike-slip movements are still active, and the bathymetry of the Gulf of Bone reflects the present day tectonic activity.