GEOLOGI DAN STUDI DIAGENESIS BATUGAMPING FORMASI BEBULU DAERAH LONGKALI DAN SEKITARNYA, KECAMATAN LONGKALI, KABUPATEN PASER, PROVINSI KALIMANTAN TIMUR

• Main Author: Dwi Rahayu, Windy
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/34255
• Institution: Institut Teknologi Bandung

Research is held in Longkali and surrounding area, Paser Districts, East Borneo Province. Geological mapping is conducted in an area of 49 kilometers2 to the scale of 1:12.500 in order to figure the geological setting in the research area. In addition, a diagenetic study of Bebulu Limestone Formation is also conducted by doing a set of analysis from analyzing its diagenetic products until reconstructing its diagenetic history. Research area landscape shows differential in terms of contour pattern and morphological surface. As a result, research area is classified into three geomorphologic unit which are Karst Hill Unit, Folded Hills Unit, and Plain Karst Unit. Geological history of research area begins in Middle Miocene when the Sandstone Unit deposition, followed by the deposition of Limestone Unit in which has an inter-fingering relationship with the Sandstone Unit. In conjunction with the limestone deposition, there is also Sandstone-Claystone A Unit deposition which takes until Late Miocene. Afterwards, Sandstone-Claystone B Unit is deposited conformed above the Limestone Unit and Sandstone-Claystone A Unit. Tectonic activity takes time in Pliocene, generating fold and fault in the research area which then observed as a tear fault. Diagenetic process which is observed in Bebulu Formation are shown within the limestone reefs and limestone clasts. Diagenetic products that are recorded in the Limestone has a cross-cutting relationship therefore the history and change of diagenetic environment can be concluded sequentially. In short, diagenetic in Bebulu Formation starts with marine phreatic, followed by meteoric phreatic and meteoric vadose, continued with burial, and at last meteoric vadose.