VULCANOSTRATIGRAPHY AND PETROGENESIS OF SUNDORO VOLCANO AND ITS SURROUNDING, WONOSOBO REGENCY, TEMANGGUNG REGENCY, CENTRAL JAWA

• Main Author: Habib, Firman
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/27356
• Institution: Institut Teknologi Bandung

Previous studies in Sundoro Volcano have examined geological settings and rock geochemistry, but, vulcanostratigraphy mapping which is accompanied with complete petrogenesis analyses was not completed by previous researchers. The aim of this study is to identify geological settings, magmatic series, and tectonic settings in Sundoro Volcano and its surroundings. Remote sensing analysis was conducted to identify geomorphological and tentative geological units, then, was proofed by field observations. The result of field observations, then, were presented on a detail geological map that was created by using the principal of vulcanostratigraphy. Petrogenesis analyses was conducted by combining thin section observation and whole rock geochemistry analyses Based on the observations, research area can be divided into eight geomorphological units, while the stratigraphy of the study area is divided into three Khuluk namely, Sundoro, Sumbing, and Dieng, which are consisted of 28 lithological units. In the study area, Khuluk Sundoro is composed by four Gumuk, namely Pagerluhur, Kembang, Kekep, and Watu. Pagerejo Sinistral strike slip was identified as secondary structure which was developed in study area. The results of field observation and petrographic analyses have shown that lithology of the study area is arranged by andesite, pyroxene andesite, pyroclastic breccia, tuff-breccia, tuff-lapili, and tuff. Combining petrographic analyses with the comparison of SiO2 content against major elements, and trace elements have indicated that magmatic processes in the study area are controlled by crystal fractionation, magma mixing, assimilation, adiabatic decompression, and convection. Based on phenocrysts abundance and geochemistry analyses were known that magmatic series in Sundoro Volcano is Calc-Alkaline, resulted from subducted plate margin then form volcanic features as Island-Arc.