Mineralisasi Bijih Timah dan Thorium Di Kabupaten Belitung Timur, Provinsi Kep. Bangka-Belitung

Belitung Island is located in the southeast of the Bangka island and east of Palembang city, known as one of the tin islands occupied by various types of granitic rocks. Geologically, the island is situated on the Bentong- Raub suture, it is the boundary of the I-type granitic rock or magnetite series in the east block and the S-type granitic rocks or ilmenite series in the west block. Based on megascopic and microscopic analysis, in the East Belitung region there are also at least has two types of granitic rocks, ie. I-type S-type. The East Belitung residence has some metal commodities that can be utilized for indusstries purposes including thorium (Th) and tin (Sn) associated with the granitic rocks above, particularly S-type. Field observations indicated that there are at least two models of geological processes that cause
mineralization or concentration of thorium, first it is concentrated on the top part of the weathered rocky granitic rock, within some faulted metasediment and as placer deposits, associated with rare earth elements (REE), present as monasite ore minerals. The tin element present as cassiterite ore minerals, is also developed by hydrothermal process within magnetite-casiterite-sulphides lode, stratabound bedding-parallel veins containing quartz-casiterite-sulphides, wolframite-casiterite-quartz veins within greisen zones as well as formed as a placer deposits scattered around the granitic
rocks body.