Publications

Prior to Tertiary sedimentation, a rugged (Pre-Tertiary) surface of highs and depressions pre-set the general shape andconf guration of the Palembang basinal area.Tertiary basinal history from the Eocene to the Lower Miocene is marked by a tensional phase with maximal rates of subsidence of faulted ",block-areas", of 0.04 cm/year, during Late Oligocene to Early Miocene times. This phase in basinal history coincides with a standstill in subduction of the Indian oceanic plate in the south below Sundaland. Oblique oriented compression of the northward converging Indian Ocean plate were instead solely accomcr dated by an intervening NW-SE trending proto-Barisan by way of lateral movements.The early Middle Miocene marked the beginning of compressive movements throughout the Paleinbang (backarc) basin, obviously connected with renewed subduction of the oceanic plate. Basinal history from the Middle Miocene on is furthermore characterized by a regression of the sea. Interactive movements among ",block-areas", resulted a.o. in positive structural inversion and tilting of blocks in opposite directions, which in turn induced typical foldshapes and patterns within Neogene strata, i.e. a progressive change in direction of anticlinal axes and opposing vergences among anticlinal structures of adjacent ",block-areas",. Syndepositional deformation of Air Benakat and Muara Enim sands took place on tilted surfaces with unconsolidated Cumai shales/clays as a plastic substratum.However, diastrophism in the Palembang Basin was mainly confined to a north-south stretching relativeiy narrow zone. Besides containing the region's highest heatflow, this ",fairway", is the site of most of the basin's hydrocarbonbearing sedimentary formations.The relations between vertical movements of blocks within the Palembang Basin, rates and directions of the converging Indian Ocean plate as proposed by Schwan (1980), and relative changes of sea level (Vail et al, 1977) with respect to paroxysmal stages of the Barisan orogen, are outlined in this study.