The petrographical and organic geochemical composition of coal from the East field, Bogovina Basin (Serbia) Dragana Životić a, ⁎, Branimir Jovančićević b , Jan Schwarzbauer c , Olga Cvetković d , Ivan Gržetić b , Marko Ercegovac e , Ksenija Stojanović b , Aleksandra Šajnović d a Faculty of Mining and Geology, University of Belgrade, Djušina 7, Belgrade, Serbia b Faculty of Chemistry, University of Belgrade, Studentski trg 16, Belgrade, Serbia c Institute of Geology and Geochemistry of Petroleum and Coal, Rhenish-Westphalian Technical University of Aachen, Aachen, Germany d Centre of Chemistry, IChTM, Studentski trg 16, Belgrade, Serbia e Serbian Academy of Sciences and Arts, Knez Mihailova 35, Belgrade, Serbia abstract article info Article history: Received 19 January 2009 Received in revised form 12 July 2009 Accepted 29 July 2009 Available online 11 August 2009 Keywords: Bogovina Basin Subbituminous coal Macerals Exsudatinite Immature hydrocarbons Biomarkers A petrological and organic geochemical study was performed on coal samples from the East field deposit, Bogovina Basin, Serbia. Fourteen coal samples were collected from different parts of the Main and Upper coal seams from fresh, working faces in the underground subbituminous coal mine. The Lower Miocene (?) coal of the East field is a typical humic coal with huminite, liptinite and inertinite concentrations of up to 81.4 vol.%, 16.1 vol.% and 13.5 vol.%, respectively. Densinite is the most abundant maceral with variable amounts of ulminite and gelinite. Sporinite and liptodetrinite are the most common macerals of the liptinite group. Exsudatinite was detected in the lower part of the Lower coal seam. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral matter consists mostly of clay minerals and carbonates. The mean random huminite reflectance (ulminite B) for the Main coal seam is 0.42±0.04%Rr, and 0.41±0.04%Rr for the Upper coal seam, which are typical for an immature to early mature stage of the organic matter. The distribution and abundance of n-alkanes and steranes indicates a significant contribution of epicuticular waxes from higher plants. High amount of phyllocladane-type diterpenoids (16α(H)-phyllocladane) suggests that coal forming plants were conifer families Taxodiaceae, Podocarpaceae, Cupressaceae, Araucariaceae, Sciadopityaceae, and Phyllocladaceae, while a higher amount of pimarane and norpimarane suggests Pinaceae, Taxodiaceae, and Cupressaceae. The pristane/phytane (Pr/Ph) ratio implies variable anaerobic to oxic conditions during sedimentation. The distribution of the hopanes detected in the Bogovina East field coal indicates an immature to early mature stage of the organic matter, which is in agreement with huminite reflectance. The high coal sulphur contents from the East field are characteristic for slightly alkaline depositional environments generated by bentonite from the basement of the Main coal seam. The petrological observation and biomarker composition provide evidence for the generation of immature hydrocarbons which, most probably, originated from the resins and waxes of higher plants, mostly gymnosperms. © 2009 Elsevier B.V. All rights reserved. 1. Introduction The intermontane Bogovina coal basin is located 220 km south- east of Belgrade (Fig. 1a), and covers an area of about 70 km 2 . The Bogovina Basin is a northeast–southwest elongated tectonic depres- sion with a maximum length of 25 km and width of 2.5 km, which is divided into two fields (Fig. 1b): West and East, which are separated by andesite rock in the palaeorelief (Cvetičanin and Novković, 1975). In the West field, there was one complex coal seam (bituminous coal; %Rr = 0.62, Ercegovac, 1998), which was exploited for nearly 90 years and now is exhausted. In the East field, there are two subbituminous coal seams, from which the studied samples were collected. The total production during the period 1990–2005 was less than 1 Mt of low- rank coal. The coal resources and reserves are estimated at 2 Mt (Milenković and Ramović, 2005). The distribution of palynomorph assemblages in the coal from the Bogovina East field (Dimić, 1988) suggests that trees and bushes played an important role in coal formation. The presence of Taxodiaceae and Cupresaceae indicates a wet forest swamp. Other palynomorph assemblages like Myrica, Alnus, Salix and Gramminae sp, are characteristic for a wet part of a swamp, while Betula, Carya, Fagus, Tilia and Cedrus are indicative for a mixed swamp and dry parts of a mire. Besides that rare coniferous pollen (Pinus) indicates the presence of a hilly region in the vicinity of the mire. International Journal of Coal Geology 81 (2010) 227–241 ⁎ Corresponding author. E-mail address: draganar@rgf.bg.ac.rs (D. Životić). 0166-5162/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.coal.2009.07.012 Contents lists available at ScienceDirect International Journal of Coal Geology journal homepage: www.elsevier.com/locate/ijcoalgeo