Paleogene sequence framework and depositional systems in the Sunda and Asri Basins, Indonesia

AbstractBased on seismic reflection characteristics, lithologic associations, and basin structure evolution stages, the Banuwati Formation, Zelda and Gita Members in the Oligocene could be divided into six third-order sequences. The new sequence framework has been established in the Sunda and Asri Basins. Sequence relationship between wells and seismic data has been implemented in the basin scale through the use of synthetical seismic records of 14 wells. Depositional systems, such as delta, fan-delta, nearshore subaqueous fan, and fluvial, are identified in the Banuwati Formation, Zelda and Gita Members. Alluvial fan, subaqueous fan, and fan delta occurred on the steep slopes of the basins. Deltas were mainly developed on the gentle slopes of the basins. There were three separated small basins with fluvial and shore-shallow lake deposition in the Banuwati Formation (SQ1). During the Lower Zelda (SQ2) sedimentation, the former separated small basins enlarged in a certain extent where delta and subaqueous ...