Dystrybucja biomarkerów i dojrzałość termiczna materii organicznej w tonsteinie i węglu kamiennym z pokładu 385/2 z kopalni Bogdanka (Lubelskie Zagłębie Węglowe)

Abstract

Biomarker`s distribution and thermal maturity of organic matter from tonstein and bituminous coal from coal seam no. 385/2, from “Bogdanka” mine (Lublin Coal Basin).A b s t r a c t: The paper presents results of geochemical analyses of organic matter (OM) in a tonstein bed and surrounding bituminous coal from the Upper Carboniferous (Westphalian B) coal seam no. 385/2 from the Bogdanka mine, Lublin Coal Basin. In all studied samples, including those of tonstein and bituminous coal, OM was found to be very similar in composition. Distribution of hydrocarbons in investigated rocks is characterized by strong predominance with odd-number carbon-atom of the long-chain n-alkanes in comparison to the even-number and high concentration of C29 steranes, what implies relatively high input of higher-plant OM in these samples. Minor concentration of C28 steranes and perylene points at presence offungi. In all extracts, the tri- and tetracyclic diterpanes co-occur with their aromatized derivatives, what suggests presence of the tap resin species – precursors of the conifer families in the plant community. The abundance of sesquiterpanes, pentacyclic triterpanes and benzohopanes indicates a significant bacterial input, most possibly connected with bacterial activity after deposition of terrestrial OM. The original material of tonstein was pyroclastic in orgin, and deposited directly on plants living at the surface of a mire. That material hadn’t had any direct influence on chemicalOMtransformation. The biomarker data, both for coals and tonstein, reveals that sedimentary organic matter was heated up to a temperature corresponding to the level of immature/start of oil window. On the other hand, the increase in thermal maturity value, based on distribution of the aromatic hydrocarbons in organic matter in tonstein (theoretical vitrinite values – Rc, Rcs) are probably due to the presence of incompletely burned organic remains (charcoals), transported to the sedimentary basin along with volcanic ashes.