ORGANIC GEOCHEMISTRY OF THE WILKINS PEAK, LANEY, AND FOSSIL BUTTE MEMBERS OF THE GREEN RIVER FORMATION, WYOMING (TERPANES, STERANES, ENVIRONMENTS)

Oilshale samples interpreted to represent fresh and saline lacustrine settings were chosen from the Green River Formation in each of the Green River and Fossil Basins. These samples were analyzed for their extractable hydrocarbon and kerogen compositions. The organic compositions of the sediments were tested for relationships and differences between (1) the fresh and saline subfacies, (2) the two basins, (3) central and marginal lake sediments, and (4) the extractable hydrocarbons and kerogens themselves.; Possible causes for the relationships and differences that were found in this study are advanced, where possible, based on current organic geochemical knowledge.; The results show the thermal immaturity of the organic materials within both basins and suggest maximum burial depths of one kilometer. Although primarily composed of algal remains (i.e. Type I kerogen) both terrestrial plant and bacterial input are also distinguishable and several parameters are interpreted to indicate the relative amounts of material derived from the latter two biological sources.; A few compounds (or parameters) were noted to exhibit differences in concentrations (or values) between the fresh and saline subfacies suggesting that they may be useful indicators of paleosalinity, while other compositional differences were noted to distinguish the two basins and suggested different biological inputs to the sediments of the two basins.