GEOLOGI DAERAH TONJONG DAN SEKITARNYA, KABUPATEN BREBES, JAWA TENGAH

Abstract

Geological mapping is basically a depiction of data on a topographic base map that produces a reflection of geological conditions at the desired scale. The research was carried out in the sub-district of Tonjong located at -7.142965176 / 108.963001573 and -7.194520833958 / 108.998851533997, The research area is ±20 km² with a length of 5 km and a width of 4 km. Knowing the distribution of rocks, stratigraphic relationships, geomorphological units and developing structures is the goal of this research. The method used is the initial stage, the field mapping stage, the laboratory activity stage, data processing, studio work, and making a Final Project report. Physiographically, the research area is included in the Bogor – North Serayu – Kendeng Anticlinorium Zone (Van Bemmelen, 1949). The rock units in the research area are composed of Andesite Lava Unit, Claystone – Sandstone Unit, Sandstone – Claystone Unit, Conglomerate Rock Unit, Pyroclastic Breccia Unit, and Tuff Breccia Unit. The geomorphology of the research area is divided into 6 geomorphological units, namely the Fault Zone Hills Unit, Fault Block Ridge Unit, Denudational Plain, Lava Flow Hills Unit, Folding Hill Unit, and Volcano Foot Unit. Based on observations and analysis of the straightness of the working force, the stress trend is northeast – southwest and northwest – southeast with the Compression regime. Geological structures that develop in the research area are Synclines and Trust Faults. Keywords: Geological Mapping, Tonjong, Physiography, Geology.