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Freshwater lacustrine shales with a good to excellent petroleum source potential from the Upper Triassic-Lower Jurassic Kap Stewart Formation in Jameson Land, Eastern Greenland, have been investigated by Rock-Eval pyrolysis, TOC and sulphur determinations, gas chromatography, mass spectrometry and pyrolysis-gas chromatography. Distributions of n-alkanes, isoprenoids, steranes and hopanes together with Rock-Eval data and sulphur contents have been used to describe depositional environment and thermal maturity. The lacustrine shales are characterized by long-chain n-alkanes, high CPI values, high pristane/phytane ratios, high hopane/sterane ratios and very low sulphur contents. Good potential for generation of liquid petroleum is confined to samples having the highest relative contents of C 27 -steranes, gammacerane and 17α(H)-trisnorhopane (Ts). Regional maturity levels correspond to an immature stage, perturbed by local heating from sills. Comparison with the time-equivalent Are Formation on Haltenbanken, offshore Mid-Norway, has been made with respect to biomarker distribution and petroleum potential. The biomarker distributions of the two formations are similar and can be ascribed to the clastic, non-marine nature of both depositional areas. The petroleum potential of the Are Formation is poorer than that of the Kap Stewart Formation, probably due to a predominantly deltaic facies of the former with major terrestrial organic matter input. |
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