ABSTRACT: Depositional systems at the continental margin: 3D seismic case study from offshore Northeast Java

Posamentier, Henry W. and Wayne A. Basden , Atlantic Richfield Indonesia, Plano, TX

Depositional systems from the continental margin offshore northeast Java were imaged using 3D seismic data. Mapping of the sea floor, horizon slices, and time slices reveal a variety of physiographic elements including incised valleys, unincised high-sinuosity channels, shelf-edge deltas, shelf edge slump scars, slope gullies, and fault scarps. The data show a Late Pleistocene incised valley feeding a shelf edge delta. This incised valley grades into an unincised alluvial system approximately 10 km from the shelf edge before feeding a shelf edge delta located on the hanging wall of an active shelf-edge fault system. The path of the valley system is influenced by syndepositional faulting, causing the system to be diverted parallel to fault scarps before crossing the faults. Slump scars mark the shelf edge at recurring intervals during the Late Pleistocene. Recurrent slumping from the shelf margin has resulted in the formation of numerous slope gullies. These observations are of significance to both explorationists as well as facilities engineers. Explorationists are provided with a detailed example of the spatial relationships of lowstand shelf-edge depositional systems, which can be applied in the analysis of exploration potential on ancient shelf margins. Facilities engineers can and are using these insights to evaluate the stability of shelf-edge substrates with regard to pipeline, facilities, and platform construction.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia