Accretion and Dispersion of Southeastern Sundaland: The Growing and Slivering of Continent and Petroleum Implications

Satyana, Awang H.
BPMIGAS, Jakarta, Indonesia.

Sundaland presently constitutes the southeastern corner of the Eurasian continental plate. Terrane analysis reveals that the Sundaland is made up of a number of terranes originating from the northern Gondwanaland which rifted, drifted, and amalgamated in the Late Paleozoic and Mesozoic.

Occupying the position of active continental margin, the Sundaland recorded the history of the growing of continent by accretion. A number of SE Sundaland accreted crustal masses has been identified: oceanic Meratus, continental Paternoster, Ciletuh-Luk Ulo-Bayat subduction complex, continental SW Sulawesi, Bantimala-Barru-Biru subduction complex, Flores Sea Islands, and continental Sumba Island. These crustal masses accreted the ‘original' SE Sundaland (Schwaner Core) during 150-60 Ma (Late Mesozoic).

Started at around 50 Ma, in the Middle Eocene, some of the accreted mass of SE Sundaland rifted and drifted apart. The dispersed masses include : SW Sulawesi, Flores Sea Islands, and Sumba Island. The dispersion of SE Sundaland is considered due to trans-tension rifting related to tectonic escape of India-Eurasia collision and/or back-arc spreading by roll-back movement of slower rate-subduction, resulting in opening of the Makassar Straits and Bone Basins, segmentation of East Java Basement and slivering of Sumba terrane.

A number of sedimentary basins developed during dispersion of SE Sundaland, provided by Paleogene tectonostratigraphic sequences with proven and potential sources, reservoirs and traps. Reconstruction of accretion and dispersion of SE Sundaland can reveal the evolution and development of the basins, important for exploration evaluation.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012