The relationship between coal petrography and depositional environments from South Sumatera Basin : A Study Case in Musirawas, South Sumatera Irfan Marwanza, Masagus Ahmad Azizi, Riskaviana Kurniawati, Subandrio, Wiwik Dahani, Taat Tri Purwiyono
Universitas Trisakti
Abstract
This study focuses on petrographic analysis and the location of coal deposition of the Muaraenim Formation in the Musibanyuasin area of South Sumatra. The purpose of this study was to determine the maturity level of coal using reflectance and the area of coal deposition using the TPI-GI diagram. In this study, petrographic examination, proximate analysis, and calorific vale were used to determine the characteristics of coal and the depositional environment of Miocene coal. Twenty-five coal samples were collected from in situ coal outcrops. The sample has a random vitrinite reflectance of 0.12 to 0.38 and is classified as sub-bituminous coal by the Coal rank classification. The following methods were used in this study: petrographic analysis, including maceral and mineral analysis- vitrinite reflectance measurement- and plotting the Tissue Preservation Index (TPI) against the Gelification Index (GI). The coal composition in the study area is composed of vitrinite dominance (82.6%), inertinite maceral 4.18%, liptinite maceral 1.54%, and mineral matter 11.6%. According to the analysis, the coal in the study area is lignite (Ro = 0.39%-0.44%). The TPI and Gelification Index (GI) plots show that the study area was in the lower delta plain environment, marsh and fen, as well as limno-telmatic depositional conditions, at the time of peat deposition.
