Publications

Java Island is an active volcanic arc that resides in the southwestern - southern boundary of Sundaland edges. The volcanic arc consists of several volcanism episodes, with a relatively younging trend northward (Late Oligocene to Pleistocene), following the Indo-Australian plates inward migration. In contrast to the prolific neighboring Northwest and Northeast Java Basins in the Northern edges of Java Island; the basin reconstruction and development in the East-West trending depression in median ranges of Java (from Bogor to Kendeng Troughs) are overlooked and lays bare the challenge to the seismic imaging due to the structural complexity of the overthrusted Neogene unit as well as immense Quaternary volcanic eruption covers. On the other hand, oil and gas seepages around the northern and central parts of the Island confirmed the active petroleum generation. Five focused window areas are selected for this study. A total of 1,893 Km sections, 584 rock samples, 1569 gravity, and magnetic data, and 29 geochemical samples (rocks, oil, and gas samples) were acquired during the study. Geological fieldwork was focused on the stratigraphic unit composition and the observable features of deformation products from the outcrops. Due to the scarcity of the Paleogene deposit exposure in the Central-East Java area, the rock samples were also collected from the mud volcano ejected materials in the Sangiran Dome. Both Bogor and Kendeng Troughs are active petroleum systems that generate type II /III Kerogen typical to the reduction organic material derived from transition to the shallow marine environment. The result suggests that these basins are secular from the neighboring basins, The Northwest and Northeast Java Basins, characterized by oxidized terrigenous type III Kerogen. The contrasting subsurface configuration between Bogor and Kendeng Troughs mainly concerns the fold-thrust belt basement involvement and the tectonic shortening effect on the formerly rift basin.