Pliocene Coal Geochemistry: Palaeovegetation and Palaeoclimate Distribution in Berau Basin, Indonesia

We investigated the distributions and concentrations of plant-derived aliphatic-aromatic biomarkers in the Pliocene coal seam from the Pliocene Sajau Formation (CSF) in Berau Basin, Indonesia. In all coal samples, the presence of these components is abundant and varied, reflecting the diversity of paleoflora species and ancient climate variations during coal sedimentation. The distribution of aromatic hydrocarbons was detected, including 1,2,7-Trimethylnaphthalene (TMN), 1,6,7-TMN, and 1,2,5-TMN, cadalene, retene, 1-methylphenanthrene (M.P.), 3-MP, Phenantherene, 1,2,-dimethylphenanthrene (DMP), 2,6-DMP, 2,7-DMP, 6-isopropyl-1-isohexyl-2-methylnaphthalene, and other polycyclic aromatic hydrocarbons (PAHs)—saturated biomarkers including oleanane, des- A-oleanane, bicadinanes, and C29 ααα 20R sterane. The distribution of higher-plant biomarkers indicated that gymnosperms relatively dominated the Lower part of CSF. In contrast, the upper part of CSF showed an angiosperm-dominated higher plant terrigenous organic matter. The most charred coal in the Lower part of CSF is predominantly composed of combustion-derived PAHs, such as Benzo[a] anthracene, fluoranthene, and benzofluoranthenes. We show the cold-warm-hot climate conditions in the Pliocene in the Berau Basin by clear evidence of the distribution of biomarkers and spore-pollen.