GEOLOGI DAERAH JIPANG DAN SEKITARNYA, KABUPATEN BREBES, JAWA TENGAH

Abstract

This research was conducted in the Jipang and surrounding areas, Brebes Regency, Central Java, with an area of about 40 km2. The research locations included Bantarkawung and Salem District. In general, this research was carried out to determine the surface geological conditions and geological history of the study area and specifically to study the geological structure in the study area based on geometric, kinematic, and dynamic analyzes. There are 4 methods used in this study including the preparation stage, the field mapping stage, the data analysis and interpretation stage, and the preparing the report stage. The geomorphology of the research area is divided into 5 geomorphological units, namely Perbukitan Lipatan, Perbukitan Zona Sesar, Perbukitan Intrusi, Dataran Denudasional Struktur Patahan, and Dataran Denudasional. The unofficial stratigraphy of this research area: Batupasir – Batulempung Tambakserang unit, Batupasir – Batulempung Ciomas unit, Breksi Citimbang unit, Batulempung – Batupasir Bangbayang unit, and Andesit Tambakserang unit. The structures that developed in this area are Reverse Right Slip Cacaban, Right Normal Slip Fault Ci Hirup, Left Slip Fault Ciomas, Right Normal Slip Fault Tambakserang. The presence of Bouma sequences in the lithology of the study area reflects that the rocks are deposited by turbid mechanism in the submarine fan system. Starting from the Batupasir – Batulempung Tambakserang unit in the middle – lower of submarine fan, then the Batupasir – Batulempung Ciomas unit in the river of middle to inner of submarine fan that interfingering with the Breksi Citimbang unit, then deposited Batulempung – Batupasir unit in lower submarine fan. Then, intruded by Andesit Tambakserang Unit. Deformation in this area begins with a thrust fault that forms an anticline, then a strike-slip fault is formed, which ends with the cutting off of the block thrust fault. The erosion process continues to form morphology as it is now.