Pustaka Ilmiah Universitas Padjadjaran

Abstrak

The Liburdinding Miocene Pamaluan Coal Mine, Pasir-Sub Basin, East Kalimantan: Origin and palaeoenvironmental implications from biomarker studies

The coals from the Liburdinding coal mine in Paser regency, Pasir Sub-Basin, East Kalimantan, Indonesia were inves-tigated with respect to organic geochemistry to determine their origin and to reconstruction the depositional environment. For this purpose, biomarker analyses have been done. The distribution of saturated and aromatic hydrocarbons of or-ganic matter in a series of Miocene Pamaluan coal formation were identified. The rank of the Pamaluan coals ranged from sub-bituminous to bituminous coals (0.46–0.55% Ro), based on measurements of huminite/vitrinite reflectance. The predominance of diterpenoids in both the saturated and aromatic fractions indicated that the main sources of organic matter were gymnosperms (conifers). The presence of hopanoid biomarkers indicates the contribution of prokaryotic organisms, such as bacteria and fungi, whereas the identification of non-hopanoid triterpenoids implies a contribution of angiosperms to the coal organic matter. The variations in compositions of biomarkers indicate changes in the water level, due to seasonal drying of the mire, which caused vegetation differences in the palaeoplant communities and changes in the dysaerobic onditions during peatification.