Facies of Quaternary Sediments In Bunga Village, North Luwuk District, Banggai Regency, Central Sulawesi

Abstract

Abstract The distribution of Quaternary sedimentary rock deposits in Indonesia is quite extensive, and one of them is in the Quaternary coral reef units, which are evenly distributed along the eastern arm of Sulawesi. The research was conducted in Bunga Village, North Luwuk District, Banggai Regency, Central Sulawesi Province. This research was motivated by the lack of geological data, so the topic of developed facies became an interesting topic to be researched. Data was collected from a cliff at the coordinates 0053′57,57.1″N-122054′43′6″E. Stratigraphic measurements aim to determine the facies, depositional environment, and sedimentation mechanisms developed in the study area. The research was conducted using the method of field data collection and laboratory analysis. Collecting field data was carried out with measured stratigraphic with a 1:100 scale and taking several rock samples. Laboratory analysis was carried out in paleontological and petrographic analysis, which was carried out to determine the composition of the constituent rock and fossil identification, especially foraminifera in thin sections of rock that were selected. Based on the study’s results, the total rock layers measured in the study area were 15 m. Facies found in the stratigraphic path of the study area are floatstone facies, rudstone facies, allochemic sandstone facies, polymict conglomerate facies. The type of deposition environment of limestone and allochemic sandstone in the study area is on the foreslope, while the conglomerate facies is included in the fan delta deposition environment. Overall, the sedimentation dynamics in this area are in a high energy environment, indicating that the facies that developed were deposited with a sediment gravity flow mechanism.The results of the analysis of fossils found Cyclammina cancellata sp., Orbulina universa sp., Globigerina bulloides sp., and Trilobatus immaturus sp., which indicates the limestone in the study area was deposited in the Late Pleistocene to early Holocene.