Publications

Regional cross sections, variably constrained by seismic, surface geology, and gravity, have been constructed across central South Sulawesi to illustrate the tectonic shortening and structural development of the continent-continent collisional Neogene orogen along the eastern margin of Sundaland. The crosssections extend from Bone Bay in the east to the Makassar Strait in the west. These cross sections, along with geochronology studies, provides an integrated view on the structural style and development of this area which has led to a better understanding of the exploration play-types expected in the region and the geologic problems remaining to be solved.The cross sections contain a complete stratigraphic succession from preTertiary basement to Eocene synrift, Oligo-Miocene post-rift, mid-Miocene synmaginatic, and fin ally late Miocene through Pliocene synorogenic sedimentary packages. The eastern portion of the cross sections represent the hinterland where Cretaceous basement is exposed on a west-vergent thrust system. Moving west of these basement outcrops is a basement-involved, westwardvergent fold and thrust belt--the Kalosi--in which Paleogene sedimentary sequences are exposed. Further west the shortening is manifested in a thin-skinned foreland fold and thrust belt terrain--the Majene-- which exposes Neogene sedimentary sequences. Two styles and scales of strike-slip faults have been recognized : lateral ramps synchronous with thrusting and later regional wrench faults associated with recent changes in plate convergence directions and with the locking of the continent-continent orogenic wedge.These cross sections are a beginning, and they place some constraint on the internal displacement of the collision that are required to produce such large scale lateral and vertical movement and the complex system of folds. South Sulawesi, therefore, represents a westvergent orogen superimposed on a mid-Miocene magmatic arc, Bone Bay represents a continentcontinent suture recently disrupted by transtensional wrenching and collapse of the orogen's eastern extremity, and Southeast Sulawesi represents the eastvergent portion of the orogen containing an allochtonous ophiolite nappes from the continentcontinent suture. The leading edge of the orogen lies along the western margin of the Banda Sea.