FASIES DAN DIAGENESA BATUPASIR FORMASI SAMBIPITU, DAERAH KABUPATEN GUNUNGKIDUL

• Main Author: Said, Salatun
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/4722
• Institution: Institut Teknologi Bandung

<b>Abstract:<p align=\"justify\"> <br /> Sandstones of the Sambipitu Formation is a gravity flow deposit within a fore arc basin of the Early- to Middle- Miocene age; it can be divided into two facies: the inner-and the mid- fan facies. More detail subdivision based on the correlation of the selected horizon and supported by orientation of the strike line, 4 (four) zones can be recognized. Petrographic study on samples of sandstone from Sambipitu Formation reveals that zone I and IV are characterized by lithic- and feldspathic- wacke, whilst zone II and III consisting of arenite- type of sandstone. Diagenetic stages of the sandstones of the Sambipitu Formation indicate that cementation is well developed in both zone II and III, includes authigenic cementation of calcite, zeolite, and clay & chlorite (producing clay rim textur); other type of cementation occured is recrystallized clay matrix that give clay coat texture. Further diagenetic phenomenas noted are compaction and dissolution processes. The formation of authigenic clay - coats & -rims began soon after the deposition and the initial compaction; followed by dissolution processes dissolving most unstabel grains such as lithic fragments, mafic minerals and plagioclase. Pore filling calcite and zeolite started to begin after compaction & disolution occured. This sandstone of the Sambipitu Formation is interpreted as stage II-III of the Galloway subdivision (1974).<p align=\"justify\">