Tectonic arrangement based on provenance analysis of the Sambipitu formation sandstone in Kali Ngalang traverse, Gedangsari, Gunungkidul, Yogyakarta

The Sambipitu Formation at Kali Ngalang, Gedangsari, Gunungkidul in Yogyakarta consists of sandstone at the top layer and carbonate sandstone at the bottom layer. It indicates that this formation was once of a transitional area between land and marine. This diverse lithology is also reflected by the minerals that make up these sedimentary rocks. The diversity of minerals that make up the sedimentary rocks of the Sambipitu Formation cannot be separated from the original rock that formed by tectonic arrangements before, during, and after. The quantitative petrographic analysis is used for naming rocks, determining the tectonic setting sediment maturity, and the source of the materials constituents. Calculating and plotting on ternary diagram of polymic quatrz, sedimentary lithic and volcanic lithic,and feldspar can reveal the make up of sedimantary rocks. Based on field observations and petrographic results, the rocks that make up the Sambipitu Formation are composed of clastic sedimentary rocks (arkosic wacke and lithic wacke) and clastic limestones (grainstone, wackestone, and packestone). The results of analysis about tectonic provenance revealed that research area is in the form of a volcanic island arc with immature sedimentary level. The origin of source material is from orogen arc that indicated as an increasing activity’s volcanic around magmatic arc area.