Proceedings, Jakarta2006 International Geosciences Conference And Exhibition
Jakarta, August 14 – 16, 2006
Docking and Post-Docking Tectonic Escapes of Eastern Sulawesi: Collisional Convergence and their Impications to Petroleum Habitat
Awang Harun Satyana*
The escape (extrusion) concept, referring to the motion of a package of rocks towards a free edge within a compressional environment, has been much described as by-product of docking (collision). While the collisional zone is represented by thrust-fold belts, the tectonic escape of blocks is accommodated by large strike-slip faults and extensional structures.
Collisional/docking zone of Eastern Sulawesi is marked by (1) overthrusting of East Sulawesi ophiolite, (2) formation of foreland Batui-Balantak fold and thrust belt, and (3) emplacement of Kolokolo melange. The K-shapedSulawesiIsland is considered to be formed by post-docking escape tectonics. The tectonics has caused: (1) arc polarity reversal of Sulawesi arms from being convex eastward to being concave eastward, (2) opening of the Gulf of Bone, (3) formation of large strike-slip faults of Palu-Koro, Kolaka, Lawanopo, Hamilton, Matano, and Balantak Faults, and (4) extensional faults in East Arm and surrounding areas.
Petroleum has been discovered and produced in this area. Docking and post-docking of the microcontinents have controlled the petroleum habitat and system. They are responsible for formation of basins and traps, sedimentation of burial and sealing deposits, generation and migration of petroleum, and preservation of accumulation. Good understanding of the docking and post-docking escape tectonics will help evaluation of petroleum possibilities in any area of collisional convergence.