Changes of Biomarkers, Isotopes and Macerals of Polish Coals and Shales: Maturation Simulated by Hydrous Pyrolysis

Summary The bitumen yields of Carboniferous coals and shales from USCB and LCB after 330oC HP are higher than in initial coals and shales and somewhat higher than of coals and shales after 360oC HP. The distribution of exsudatinite in coals is higher at 330°C and decreases at 360°C HP. Contrary to shales at 360°C HP the exsudatinite content slightly increases. This phenomenon could be caused by the presence of clay minerals in shales which have a general retention effect during hydrocarbon generation. The results of biomarker and isotope analyses reveal that bitumen is always co-genetic with corresponding kerogen in coals and shales, and their deposition was in a brakish-lacustrine environment, and the microbially reworked organic matter could be caused by: (i) contribution of planktonic or benthic algae organic matter, (ii) more anoxic conditions in sedimentation basin, which impede bacterial growth and reworking of organic matter and (iii) contribution of terrestrial organic matter was higher than in other cases, and more organic matter could preserve in primal form.