#TITLE_ALTERNATIVE#

• Main Author: CHANDRA R.M. (NIM : 120 12 005), MUHAMMAD
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23211
• Institution: Institut Teknologi Bandung

Pangalengan, West Java, is located on highland area surrounded by Quaternary volcanic complex. This research study is aiming to understand the geological setting, detailed volcano stratigraphy, and hydrothermal alteration in Southern Pangalengan. This research covers 98 km2 area, with UTM coordinate between 776000 – 790000 mT and 9196000 – 9203000 mU, datum WGS84 zone 48S. The research methods comprise topography map and SRTM image analysis, geological mapping and sampling to determine distribution of lithology, volcanostratigraphy and alteration zone in the research area. Petrographic and XRD (X-ray Diffraction) analysis is used to validate lithology type and alteration minerals in the research area. Geomorphological unit in the research areaconsists of 10 units, they are Haruman Kidul Pyroclastic Slope Unit, Ujungan Lava Hills Unit, Puncak Cacing Lava Mountains Unit, Pyroclastic Slope Unit, Kuda Caldera Ridge Unit, Pangalengan Intervolcanic Plateau Unit, Wayang Pyroclastic Slope Unit, Kamiru Pyroclastic Slope Unit, Windu Lava Dome Unit, and Cileunca Lake. Based on geomorphological analysis, the research area is categorized as young geomorphological stage. Volcanostratigraphy of the research area is divided into 3 Khuluk and 6 Gumuk, The Khuluk consists of Khuluk Kencana, Khuluk Kuda, and Khuluk Malabar. The Gumuk consists of Gumuk Ujungan, Gumuk Haruman Kidul, Gumuk Puncak Cacing, Gumuk Kuda, Gumuk Wayang, and Gumuk Windu. Volcanostratigraphy units of the research area consists of 18 units, they are Ujungan Andesite Lava 1 (Ul1), Ujungan Andesite Lava 2 (Ul2), Ujungan Pyroclastic Fall Lapilistone (Uj), Haruman Kidul Andesite Lava (Hl), Haruman Kidul Pyroclastic Flow Breccia 1 (Ha1), Haruman Kidul Pyroclastic Flow Breccia 2 (Ha2), Puncak Cacing Andesite Lava 1 (Pcl1), Puncak Cacing Andesite Lava 2 (Pcl2), Kuda Andesite Lava 1 (Kl1), Kuda Pyroclastic Flow Breccia (Ka), Kuda Andesite Lava 2 (Kl2), Pangalengan Pyroclastic Fall Tuff 1 (Pgj1), Pangalengan Pyroclastic Flow Breccia (Pga), Pangalengan Pyroclastic Fall Tuff 2 (Pgj2), Wayang Pyroclastic Flow Breccia (Way), Windu Pyroclastic Flow Breccia (Wda), Windu Andesite Lava (Wdl), and Aluvium Cileunca. Geological structure of the research area could be classified into 2 type, the primary structure consists of sheeting joint, columnar joint, and autobreccia. The secondary structure of the research area consists of Cibaliung 1 Dextral Fault, Cibaliung 2 Dextral Fault, Waringin Sinistral Fault, Banjarsari Normal Fault, and Citawa Dextral Fault. Hydrothermal alteration of the research area could be divided into 3 system, Cayur Alteration System located in southern Mt. Ujungan, formed after Ujungan Lava formation, consists of advance argillic alteration type, Bunikasih Alteration System located in western research area, formed after Cibaliung Fault, consists of phyllic, sub-propylitic, and argillic alteration type which are correlated to Bunikasih Epithermal Low Sulphidation Deposit. Windu Alteration System, located in eastern research area, formed after Citawa Fault, consists of advance argillic alteration type and associated with Wayang Windu geothermal system. The geological history of the research area could be explained with 5 phase which are happened in Pleistosen Eon, started from Mt. Kencana formation, followed by Mt. Kuda formation, the next stage is the filling of Pangalengan plain deposits, formation of Mt. Wayang – Windu, and Citawa Faulting followed by hydrothermal alteration around Mt. Windu area.