The Control Of Geological Structure At Songgo River Dyke Intrusion In Nanggulan Formation, Western Part Of Yogyakarta-Central Java

Abstract

This study to explain the presence of intrusive rocks in Naggulan Formation was carried out with a series of geological research methods. The method used in this research is through reference studies from previous research, observing the image of the study area and its surroundings, direct observation of Paleogenic rock bodies, and measurement of fault structures, joints, and folds in the field. Measurement of the elements of geological structure is used to determine the main structure and stress forming structure in Nanggulan Formation rock which is of Paleogene age and surrounding rocks which are Neogene age. The igneous rocks found in the study area is a dyke that cut the sedimentary rock layers of Nanggulan Formation. Dyke igneous rock distribution in the study area forms a northwest-southeast (NW-SE) direction. The distribution of igneous rocks is controlled by geological structures with the main stress direction of northwest-southeast which creates extensional vertical fractures in the direction of the main compressional stress source.