PALEOGENEGRAFI DAERAH CILACAP, JAWA TENGAH

PROCEEDINGS JOINT CONVENTION BALI 2007
The 32^nd HAGI, The 36^th IAGI, and The 29^th IATMI Annual Conference and Exhibition

PALEOGENEGRAFI DAERAH CILACAP, JAWA TENGAH

Praptisih * dan Yahdi Zaim **

^*Puslit Geoteknologi – LIPI, email : praptisih@geotek.LIPI.go.id
**Prodi Teknik Geologi FKTIM Institut Teknologi Bandung, email : zaim@gc.itb.ac.id.

ABSTRACT

Studied Area is situated in Cilacap District, is a bay with the rapid development on the settlement, industries, harbor and an agricultulture.

The study of stratigraphy sedimentology/granulometry and paleontology carried out on the Quaternary sediment samples taken from 9 bore holes with the depth ranging 21 to 35 m permitt to reconstruct the paleogeography of the Cilacap Area.

The Quaternary basin of the Cilacap Area with the Tertiary sediments as a basements of the basin have been formed by Plio-Pleistocene tectonic activities. The sedimentation in the western part of the basin is represented by fine grain sediments of Clay Unit deposited in the lagoonal environment, then sedimentation in the swamp and mangrove at the middle part of the basin and toward to the east, the sedimentation were changed in to the estuary dominated by river systems in high energy as represented by the coarse grain sediments of gravely sands and conglomerates.

The river sistems brought the sediment materials derived from denudation and erosion processes of the Tertiary sediments and then deposited in the Quaternary basins of the Cilacap Area formed the development of progradations of new coastal line.

The Paleogeographic of the coastal line during Quaternary could be as reference prediction of the sedimentation as well as denudation processes for the future development planing of the Cilacap Area.