| Two triterpanes, often called “C<sub>z</sub>” and “C<sub>x</sub>,” are also empirically associated with terrestrial organic matter, but their origin is unknown. They can be seen in [[:file:oiloil-and-oilsource-rock-correlations_fig8-26.png|Figure 4]]. C<sub>z</sub> has also been called compound X<ref name=ch08r42>Philp, R., P., Gilbert, T., D., 1986, Biomarker distributions in oils predominantly derived from terrigenous source material, in Leythaeuser, D., Rullkötter, J., eds., Advances in Organic Geochemistry 1985: New York, Elsevier, p. 73–84.</ref> and has been shown to be a diahopane.<ref name=ch08r39 /> C<sub>x</sub> is probably a neohopane. They often co-occur with other terrestrial markers, such as high C<sub>29</sub> steranes, oleanane, and bicadinanes, but they can also occur alone. | | Two triterpanes, often called “C<sub>z</sub>” and “C<sub>x</sub>,” are also empirically associated with terrestrial organic matter, but their origin is unknown. They can be seen in [[:file:oiloil-and-oilsource-rock-correlations_fig8-26.png|Figure 4]]. C<sub>z</sub> has also been called compound X<ref name=ch08r42>Philp, R., P., Gilbert, T., D., 1986, Biomarker distributions in oils predominantly derived from terrigenous source material, in Leythaeuser, D., Rullkötter, J., eds., Advances in Organic Geochemistry 1985: New York, Elsevier, p. 73–84.</ref> and has been shown to be a diahopane.<ref name=ch08r39 /> C<sub>x</sub> is probably a neohopane. They often co-occur with other terrestrial markers, such as high C<sub>29</sub> steranes, oleanane, and bicadinanes, but they can also occur alone. |