For illustrative purposes, we discuss here differences in the characteristics of group I and group IV oils.<ref name=ch08r30 /> The group I oils are very low in sulfur (13C values more negative than –28.0 ‰. Concentrations of diasteranes, steranes, 4-methylsteranes, and gammacerane are low; ''n''-propylcholestanes (C<sub>30</sub> steranes) are absent. A distinctive odd-carbon ''n''-alkane dominance and a waxy appearance to the [[gas chromatogram]] of these oils is evident. These and other features suggest a freshwater lacustrine depositional setting. | For illustrative purposes, we discuss here differences in the characteristics of group I and group IV oils.<ref name=ch08r30 /> The group I oils are very low in sulfur (13C values more negative than –28.0 ‰. Concentrations of diasteranes, steranes, 4-methylsteranes, and gammacerane are low; ''n''-propylcholestanes (C<sub>30</sub> steranes) are absent. A distinctive odd-carbon ''n''-alkane dominance and a waxy appearance to the [[gas chromatogram]] of these oils is evident. These and other features suggest a freshwater lacustrine depositional setting. |