Publications

The Cenozoic history of western Sulawesi was influenced by the development of the Makassar Straits to the west and the collision of continental, ophiolitic and island arc fragments to the east. These fragments include those of the East Sulawesi ophiolite and the microcontinents of Buton, Tukang-Besi and Banggai -Sula. The ages attributed to the collision events range from early to late Miocene. (e.g. Kundig, 1956, Audley-Charles et al, 1972, Hamilton, 1979, Fortuin, 1990, Davies, 1990, Smith & Silver, 1991, Daly et al, 1991, Bergman et al, 1996, Hall, 1996, and Parkinson, 1998). Although all the fragments are small, the effects of their collisions have been inferred to have caused tectonic events throughout the region, for example, they have been used to explain inversion(s) in the Kutai Basins of Kalimantan (e.g. Daly et al, 1991, van de Weerd & Armin, 1992) and subsidence of the Makassar Straits (Bergman et al, 1996). The product of the collisions in Sulawesi was uplift, erosion and deposition of the Celebes Molasse first described by Sarasin and Sarasin (1901). However, this is not a single stratigraphic unit and rocks assigned to this formation have ages ranging from early to late Miocene (Simandjuntak et al, 1994, Sukamto, 1973, Sukamto, 1975).The Lariang and Karama basins in central western Sulawesi border the east Makassar Straits. In this area of approximately 10000km2 there is a sequence of Cenozoic sediments, including the Celebes Molasse, that have not been dated, described or interpreted in any detail. These sediments should record collision events in Sulawesi, as well as the events which led to the formation of the Makassar Straits. Field studies, detailed biostratigraphy and remote sensing data have been used to map and establish a stratigraphy modified in part from earlier work by GRDC (Hadiwijoyo et al, 1993, Ratman and Atmawinata, 1993, Sukamto, 1973).