Geology and geological interpretation based on remote sensing imageries of Nglanggeran area, Bantul residence, special province of Yogyakarta, Indonesia

A geological research has been conducted in Nglanggeran area, Bantul Residence, Special Province of Yogyakarta, Indonesia. This research covers many geological aspects as geomorphology, lithology and geological structure of the study area. The study area is aligned within longitudes from 1l0°32’0.0”E to l10°34’45.0”E and latitudes from 7°50’45.0”E to 7°53’30.0”S. This study is carried out to fulfil the needs for ar1 updated geological map of Nglanggeran area with the scale of 1:25,000. Fieldwork and laboratory analysis are carried out in this research. All the geological aspects namely the rock descriptions, geomorphology and geological structures have been observed and recorded during field observations. There are main seven lithology units that have been found in the study area composed of pumice breccia unit, andesite breccia unit, andesitic lava unit, tuffaceous sandstone unit, carbonated sandstone unit and marl unit. Pumice breccia unit of Semilir Formation is the oldest
rock unit and marl unit of Oyo Fonnation is the youngest in the study area. Joint, fault fold and other geological structures have been identified in the field. According
to the fault analysis and joint analysis, it is shown that the major force is trending from the direction of northeast and southwest. The geological interpretation based on remote sensing imageries of Nglanggeran area was the second objective of the research. The remote sensing images that were used in this research are Landsat Enhance Thematic Mapper (ETM +7), Digital Surface Model (DSM), Shuttle Radar Topography Mission (STRM) and TERRASAR. The analysis was employed by using the software of ER Mapper. Relief, morphology, drainage flow and geological structure are the geological components that have been observed in the imageries. The geological map is produced with revealing all those geological features that have been found in the Nglanggeran area.