Geologi Daerah Kedewan dan Sekitarnya, Kabupaten Bojonegoro, Jawa Timur

Abstract

Hesa Rahmaddisa. 101217079. Geology of kedewan and Surrounding Areas, Bojonegoro, East Java. Geological mapping is basically a depiction of data on a topographic base map that produces a reflection of geological conditions at the desired scale. This geological mapping is used to identify and study surface geological information including geomorphological conditions, geological structures, sedimentology and stratigraphy as well as other geological aspects. The geological mapping to be carried out is located in the Kedewan sub-district with an area of ± 20 km² with a length of 4 km and a width of 5 km. Geographically, the research area is located in -7.04814724/ 111.66341111 and -7.08449117 / 111.70956941. This research is intended as a requirement for passing the final project subject in the Geological Enginering Study program, Pertamina University with a weight of 5 Semester Credit Units. Physiographically,Research area is included in the South Rembang Anticlinorium – Randublatung Zones (Husein, 2016) with anticlinal hills geomorphological ranges . Field observations and literature studies will be carried out as long as the research is carried out, Furthermore for analysis and preparation off geological map, sample were taken in the field as primary data. The research area has 6 geomorphological units, that is : anticline hills, syncline valleys, flood plains, denudational peneplains, denudational hills and structural hills. The research area has 5 litological units that found in the area, that is: marl rock unit, limestone unit 1, marl limestone unit, limestone unit 2 and alluvium unit. The geological history in the study area was influenced by 2 phases, which is the transgression phase where marl rock unit, limestone unit 1, marl limestone unit were deposited, after that an uplift phase occurred during the pliosen-pleistocene until now which deposited limestone unit 2 units and alluvium deposits. This uplift phase also caused the formation of folds and faults in the study area.