Portal de Periódicos da CAPES

Late Cenozoic sedimentary and tectonic history of south Buton, Indonesia

1990; Pergamon Press; Volume: 4; Issue: 2 Linguagem: Inglês

10.1016/0743-9547(90)90010-b

1879-1832

A.R. Fortuin, M.E.M. De Smet, S. Hadiwasastra, L.J. Van Marle, S.R. Troelstra, S. Tjokrosapoetro,

Geological formations and processes

A description and interpretation are given of the Upper Cenozoic sedimentary record of south Buton. Various sections and outcrops were studied and sampled for their microfossil content, to provide age and paleobathymetrical data. Together with information from the literature, these data from the base for a geohistory analysis to evaluate the vertical motions. Deposition started some 11 Ma ago, after the main deformation of the island, which was related to the collision of a microplate carrying Buton, with the southeast arm of Sulawesi. Coarse and fine terrigenous debris accumulated in a rapidly subsiding foreland basin; subsidence may have exceeded 100 cm/ka. When the rate of subsidence decreased a late Miocene-early Pliocene period of quiet pelagic sedimentation followed. From the late Pliocene onwards (around 3.5 Ma bp) an overall uplift took place, with rates between 30–120 cm/ka. This drastic change is explained by the collision of Buton with a submerged microcontinent that presently forms the Tukang Besi platform, situated southeast of Buton, which interaction resulted in wrench type tectonics and a clockwise rotation of over 60° for south Buton.