A depositional setting variation and its effect to the coal quality of Warukin formation in Satui Area, South Kalimantan: Insight from maceral, biostratigraphy, electrofacies and lithofacies analyses

Warukin Formation is one of the coal bearing formation in Kalimantan that has significant coal resource. The formation as Middle Miocene Age and deposited in generally regression stage. In addition to coal, it is composed of mudstone and sandstone with siderite nodule, with some coal seams also have parting of carbonaceous mudstone. Coal from Warukin has various quality that possibly related to the changes in depositional environment. This study attempted to understand the relation between depositional environment and the coal quality. To do that, coal is sampled from coal seams that can be found in study area. After collected, the sample then analyzed using lithofacies, electrofacies, biostratigraphy, and maceral analysis. These various analyses would uncover the slight variation on depositional setting between each seam in study area. Later, the result then correlated with the coal quality analyses that have been done before. From the study, it is concluded that some coal sample has higher Sulphur content that related with deposition with more seawater influence. Biostratigraphy analyses indicate that the interburden deposited in shallow marine setting, thus indicate that the depositional interchanged between transitional setting to shallow marine. Electrofacies also indicate that there were progradation and retrogradation process in the depositional activities. Maceral studies also indicate different type of maceral component that reflect the depositional variation within the seam.