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Line 58: − [[file:oiloil-and-oilsource-rock-correlations_fig8-28.png|thumb|{{figure number|6}}Gammacerane in the m/z 191 mass chromatograms of two genetically related oils from southern Sicily. From Ocampo et al.;<ref name=ch08r35>Ocampo, R., Riva, A., Trendel, J., M., Riolo, J., Callot, H., J., Albrecht, P., 1993, Petroporphyrins as biomarkers in oil-oil and oil-source rock correlations: Energy & Fuels, vol. 7, p. 191–193, DOI: 10.1021/ef00038a005</ref> reprinted with permission from American Chemical Society.]]+ + + + − − [[file:oiloil-and-oilsource-rock-correlations_fig8-29.png|thumb|left|{{figure number|7}}Samples with gammacerane, but in this case gammacerane essentially coelutes with the C<sub>31</sub>-22R epimer. From Mattavelli and Novelli;<ref name=ch08r29>Mattavelli, L., Novelli, L., 1990, Geochemistry and habitat of the oils in Italy: AAPG Bulletin, vol. 74, p. 1623–1639.</ref> reprinted with permission from AAPG.]]
Organic compounds: environmental indicators (view source)
Revision as of 20:05, 16 June 2014
, 20:05, 16 June 2014→Gammacerane
==Gammacerane==
==Gammacerane==
<gallery mode=packed heights=300px widths=300px>
oiloil-and-oilsource-rock-correlations_fig8-28.png|{{figure number|6}}Gammacerane in the m/z 191 mass chromatograms of two genetically related oils from southern Sicily. From Ocampo et al.;<ref name=ch08r35>Ocampo, R., Riva, A., Trendel, J., M., Riolo, J., Callot, H., J., Albrecht, P., 1993, Petroporphyrins as biomarkers in oil-oil and oil-source rock correlations: Energy & Fuels, vol. 7, p. 191–193, DOI: 10.1021/ef00038a005</ref> reprinted with permission from American Chemical Society.
oiloil-and-oilsource-rock-correlations_fig8-29.png|{{figure number|7}}Samples with gammacerane, but in this case gammacerane essentially coelutes with the C<sub>31</sub>-22R epimer. From Mattavelli and Novelli;<ref name=ch08r29>Mattavelli, L., Novelli, L., 1990, Geochemistry and habitat of the oils in Italy: AAPG Bulletin, vol. 74, p. 1623–1639.</ref> reprinted with permission from AAPG.
</gallery>
In addition to the hopane family, several other types of triterpanes that are occasionally encountered can be very useful in correlations. Gammacerane is often found in sediments deposited under abnormal salinites, including lacustrine facies. Identification of gammacerane can be difficult, however, both because it is usually only a minor component and because it elutes at different places with different chromatographic columns.
In addition to the hopane family, several other types of triterpanes that are occasionally encountered can be very useful in correlations. Gammacerane is often found in sediments deposited under abnormal salinites, including lacustrine facies. Identification of gammacerane can be difficult, however, both because it is usually only a minor component and because it elutes at different places with different chromatographic columns.
[[:file:oiloil-and-oilsource-rock-correlations_fig8-28.png|Figure 6]] shows gammacerane in the m/z 191 mass chromatograms of two genetically related oils from southern Sicily. In this example, gammacerane elutes after the C<sub>31</sub> homohopanes. Note also the relative increase in the C<sub>34</sub> and C<sub>35</sub> homohopanes. The presence of gammacerane and the homohopane distribution suggest a strongly reducing, possibly carbonate or hypersaline depositional setting for the source rock of these oils.
[[:file:oiloil-and-oilsource-rock-correlations_fig8-28.png|Figure 6]] shows gammacerane in the m/z 191 mass chromatograms of two genetically related oils from southern Sicily. In this example, gammacerane elutes after the C<sub>31</sub> homohopanes. Note also the relative increase in the C<sub>34</sub> and C<sub>35</sub> homohopanes. The presence of gammacerane and the homohopane distribution suggest a strongly reducing, possibly carbonate or hypersaline depositional setting for the source rock of these oils.