Publications

The offshore Malingping Block, Southwest Java, is characterized by a series of extensional structures formed during the Cenozoic in the shallow shelf. Structural features comprise alternating basins and structural highs named, from west to east, the Ujungkulon High, Ujungkulon Low, Honje High, West Malingping Low. The shelf edge runs approximately ENE-WSW immediately south of the block. Three major structural trends influenced the deposition of Cenozoic sediments: NNE-SSW, NESW and E-W. In the Late Eocene, N-S trending structures were developed in West Java and offshore NW Java Sea basins due to E-W extension. In SW Java movement on west-dipping NNE-SSW normal faults formed a depocentre within the Ujungkulon Low. The faults are the initial grabenforming structures as indicated by eastwardthickening of Upper Eocene to Upper Oligocene strata. The NE-SW faults are parallel to the Cretaceous subduction margin in Java and are interpreted to be the result of interaction between EW extension and an older basement fabric. In the shelf edge area, E-W trending normal faults were active in the Late Eocene and Early Oligocene. Global sea level fluctuations may have influenced facies changes during the Oligocene. There were reefal limestone build-ups on structural highs during the Late Oligocene and Early Miocene. In the Early Miocene movements on east-dipping faults created the full-graben geometry of the Ujungkulon Low. Volcanism in the Early Miocene is suggested to have terminated carbonate deposition. The block has a history of extension, with changes in the position and orientation of active faults during the Cenozoic. There was minor inversion during the Early Miocene but little other evidence for contractional structures. The block experienced a major period of uplift in the Late Pliocene, resulting in a regional unconformity, followed by renewed subsidence.