#TITLE_ALTERNATIVE#

• Main Author: HIDAYAT (NIM : 12012036), SYAHRIL
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31178
• Institution: Institut Teknologi Bandung

<p align="justify">Sebuku Island, South Kalimantan is famous for having the largest latheritic iron ore reserve <br /> in Indonesia. Exploration is still underway to know the resource potential of other prospects on this green island. In this study, geological mapping, rock geochemistry (XRF analysis) and petrographic analysis were conducted to study other potentials in Sebuku Island. <br /> Geographically, the research area is located in 432340 – 437040 mT and 9616490 – 9621625 mU, zone 50 S and WGS 84 (+13 km2). Geomorphology of the research area can be divided into three geomorphological units, namely: Structural Ridge Unit, Denudational Plain Unit, and Lava Hill Unit. The stratigraphy of research area is composed by four unofficial lithological unit, aged Jura-early Cretaceous, namely: Ultramafic Rocks Unit, Basalt Unit, <br /> Diorit Unit, and Breccia Unit. There are 5 faults, Kalang Batang Left Reverse Fault (NWSE), North Kalang Batang Normal Fault (NW-SE), Madang and Sebuku east Coast Reverse <br /> Fault (NE-SW). Based on petrographic analysis, ultramafic rocks consist of strongly serpentinized (70% - 100%) dunite, harzburgite, and wherlite. <br /> Basalt had ocean floor metamorphism and hydrothermal alteration zones propylitic. While diorit had hydrothermal alteration zone of phyllic/sericitic. Geochemically, the research area has two types of magma affinity: low-K (tholeiite) series and calc alkaline-alkaline series. Low-K (tholeiite) rocks series consist of ultramafic rocks <br /> (dunite and harzburgite) and basalt and is a part of the island arc/back arc ophiolite. Calc alkaline-alkaline rocks series consist of gabbro and diorite and is related to active continental margin rock. Evolution of magmatism identified from Harker diagram showed FeO increase as magma differentiated for tholeiite rock series and decrease on calc alkaline-alkaline rock series. MgO and CaO decrease as magma differentiated for both rock series. K2O and Na2O increase as magma differentiated for both rock series. <br /> Mineralization potential of the research area include primary chromite and gold. Primary chromite was derived from ophiolite complex rocks, with its location estimated to be at the southeast of the research area. Gold potential is estimated to be located in the north Kalang <br /> Batang, with ophiolite rocks (ultramafic rocks and basalt) as host and as a result of hydrothermal alteration caused by intrusions of calc alkaline-alkalinerock series (gabbro <br /> and diorite).<p align="justify">