Evolution of the Salawati structures, eastern Indonesia: A frontal Sorong Fault deformation*
Awang H. Satyana 1), Margaretha E.M. Purwaningsih 2), and Enrico C.P. Ngantung 1)
1) Badan Pelaksana Kegiatan Hulu Minyak dan Gas Bumi, Jakarta; 2) Geology Department – Institute of Technology Bandung, Bandung
* Indonesian Association of Geologists, 31st Annual Conference, Surabaya, September 30 – October 2, 2002
Major Sorong Fault, a WSW-ENE trending left-lateral wrench fault terminates the Salawati Basin to the north and northwest. The fault has strongly controlled the basin’s structures since the mid-Pliocene and responsible for the present structural style of the basin. Four structural grains can be recognized : normal faults, strike-slip faults, fold-reverse fault belts, and diapiric structures. Four structural trends can be recognized : Salawati, Klasofo, Walio, and Cenderawasih trends. Based on left-lateral strain ellipsoidal analyses, the structural evolution can be grouped into four episodes commenced by the Sorong Fault initiation in the mid-Pliocene and peaked in the Pleistocene time when structures in the Sele Strait took place. Sequential shear-strain ellipsoids show that the Salawati structures evolved and rotated counter-clockwisely in constant magnitude of 25º relative to the present Sorong Fault from the mid Pliocene to the Pleistocene. Sorong Fault tectonism strongly controls the petroleum system of the Salawati Basin.
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