CHARACTERISTICS AND MINERALIZATION OF MANAGESE IN MARONGE AND LAPE, SUMBAWA REGENCY, WEST NUSA TENGGARA PROVINCE

• Main Author: Nursanti, Vany
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/79643
• Institution: Institut Teknologi Bandung

Manganese deposits in Indonesia have diverse characteristics, especially related to differences in geological and environmental conditions in various regions. Manganese is commonly found in minerals such as manganite, rhodonite, rhodochrosite, and pyrolusite. The main manganese-bearing ore in Indonesia is typically pyrolusite and psilomelane. Manganese mineralization is indicated in the Maronge and Lape regions. In the Maronge area, manganese mineralization is found among andesite rocks and andesite breccia in the form of boulders and outcrops. Chemical analysis of manganese boulders indicates the highest manganese content with Mn total at 20.53 %w/w, MnO2 at 25.83 %w/w, and MnO at 5.43 %w/w. Meanwhile, the outcrop of manganese rocks shows the highest manganese content with Mn total at 12.34 %w/w, MnO2 at 9.33 %w/w, and MnO at 8.32 %w/w. Manganese minerals identified in the Maronge area include pyrolusite and braunite associated with piemontite, quartz, calcite, plagioclase, and fossils. In the Lape area, manganese is found in the form of boulders, subcrop, and float among andesite rocks. Chemical analysis reveals the highest manganese content with Mn total at 20.53 %w/w, MnO2 at 25.83 %w/w, and MnO at 5.43 %w/w. Manganese minerals in the Lape area include pyrolusite associated with hematite, hydrous iron oxide, piemontite, and quartz. The calculation of major and trace element data in the Nicholson diagram (1992) indicates that the manganese deposits in the Maronge and Lape area are sedimentary-type manganese deposits, with a deposition environment transitioning from freshwater to shallow marine.