SE Sundaland accretion: palaeomagnetic evidence of large Plio- Pleistocene thin-skin rotations in Buton

Abstract

The Tukang Besi Platform, an Australian microcontinental fragment, began docking with Sundaland in the Pliocene, impacting on east Buton (SE Sulawesi). Fortuin et al. (1989) postulated that south Buton had rotated clockwise through about 60° relative to central/north Buton in response to the Tukang Besi collision. A palaeomagnetic investigation was carried out to test this model. Effectively the Buton data provide spot markers on cover sequences that have been locally deformed as "thin-skin' sheets. The underlying basement may have experienced the large relative motions proposed by Fortuin et al. (1989) but the upper Cenozoic cover has not been deformed in such a simple way. This study demonstrates that thin-skin sheets associated with continental collision may undergo 30-60° rotations within very short intervals (<2-3 Ma). -from Authors