VOLCANOSTRATIGRAPHY AND PETROGENETIC STUDIES OF KELUD VOLCANO AND SURROUNDING AREA, GANDUSARI SUB-DISTRICT, BLITAR DISTRICT, EAST JAVA

• Main Author: NURALAM INDRIYANTO (NIM : 120 12 022), JANANDA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/28222
• Institution: Institut Teknologi Bandung

<p align="justify">Research is held in Kelud and surrounding area, Gandusari Sub-District, Blitar District, East Java covering 110 km2 area. The purpose of this geological mapping is to study the geological setting in research area that are including geomorphology, stratigraphy, structure, and geological history with the principle of volcanostratigraphy and rock geochemistry of <br /> Kelud Volcano. Remote sensing analysis, petrography, structural analysis, and geochemistry using XRF (X-Ray Flourescence) analysis are used to understand magmatism activity and tectonic settings of Kelud Volcano and its surrounding area. The area landscape is related to lithologic constituent and geological structures in the area. Then, the research area is divided into eight geomorphologic units, Lahar Plain Unit, Pyroclastic Flow Hillside Unit, Inter Volcanic Plain Unit, Pyroclastic Flow Fan Unit, Lava Dome Unit, Lava Flow Ridge Unit, Volcanic Crater Unit, and Pyroclastic Fall Fan Unit. Geomorphic stage in the research area is young to mature stage with radial and rectangular drainage patterns. Stratigraphy in the research area is divided into two khuluks, namely <br /> Anjasmoro Khuluk and Kelud Khuluk. Kelud Khuluk has five gumuks, namely Kalingobo1 Gumuk, Kalingobo2 Gumuk, Kalingobo3 Gumuk, Umbuk1 Gumuk and Umbuk2 Gumuk. The Rocks from those khuluks and gumuks consist andesite, lapilli-tuff, pyroclastic breccia, laharic breccia which are divided into 19 rock units based on source, the unit formation time, and lithology that are distinguished by size, component richness, and phenocryst of the rocks. Structural feature in the area consist of primary and secondary structure. The primary structures in the study area are columnar joints, sheeting joints, autobreccia, vesicular, and coherent structure. The secondary structures in the study area are Gunung Umbuk Crater, <br /> Gunung Kelud Crater, and Puncu Normal Fault. Based on phenocryst richness, geochemistry from major and trace elements analysis, magma series of Gunung Kelud and surrounding area is Calc-Alkaline Basalt from tectonic feature of Active Continental Margin.<p align="justify">