Cenozoic palaeogeographic evolution of Sulawesi and Borneo

Sulawesi and Borneo are located in the middle of the Indonesian Archipelago, an area which has been extremely tectonically active throughout the Cenozoic. This paper compiles current knowledge on the geology and palaeogeography of this complex region and includes the first attempt to synthesise palaeogeographic data onto plate tectonic reconstructions. Construction of palaeogeographic maps helped to identify some of the strengths and weaknesses of current plate tectonic models for the region, thereby highlighting areas where further geological research is required. Palaeogeographic maps presented, using plate tectonic reconstructions as a base, illustrate the evolution of Borneo and Sulawesi and highlight important changes in the environment during the Cenozoic. The Tertiary geological history of eastern Borneo and Sulawesi is inextricably linked to the progressive accretion of continental and oceanic material from the east, onto the eastern margin of Sundaland, and to the resultant development of volcanic arcs. Large tracts of western Sulawesi, eastern Borneo, the East Java Sea and the Makassar Straits formed an extensive basinal area throughout much of the Tertiary. Implications for plate tectonics, exploration for natural resources and biogeography are discussed from the palaeogeographic reconstructions of Sulawesi and Borneo.