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[[Isotopes of carbon|δ<sup>13</sup>C]] values of cholestane reflect the carbon isotope composition of the animals that created the original cholesterol molecules. Animal carbon isotope composition is typically understood to be a function of their diet;<ref>{{Citation|last=Hayes|first=John M.|chapter=3. Fractionation of Carbon and Hydrogen Isotopes in Biosynthetic Processes|date=2001-12-31|pages=225–278|publisher=De Gruyter|isbn=9781501508745|doi=10.1515/9781501508745-006|title=Stable Isotope Geochemistry}}</ref> therefore, carbon isotope composition of cholestane would reflect this original diet value as well. δ<sup>13</sup>C values can be measured using a gas chromatograph coupled to an IRMS. |
[[Isotopes of carbon|δ<sup>13</sup>C]] values of cholestane reflect the carbon isotope composition of the animals that created the original cholesterol molecules. Animal carbon isotope composition is typically understood to be a function of their diet;<ref>{{Citation|last=Hayes|first=John M.|chapter=3. Fractionation of Carbon and Hydrogen Isotopes in Biosynthetic Processes|date=2001-12-31|pages=225–278|publisher=De Gruyter|isbn=9781501508745|doi=10.1515/9781501508745-006|title=Stable Isotope Geochemistry}}</ref> therefore, carbon isotope composition of cholestane would reflect this original diet value as well. δ<sup>13</sup>C values can be measured using a gas chromatograph coupled to an IRMS. |
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More generally, steranes can be used as an indicator of environmental shifts. A study has presented δ<sup>13</sup>C values of steranes versus [[hopane]]s and used it to propose changes in the photic zone over the course of the [[Miocene]], as changes in the isotope value must be either a result of dissolved inorganic carbon within the water or biological [[isotope fractionation]].<ref name="Schoell 1122–1125"/> |
More generally, steranes can be used as an indicator of environmental shifts. A previous study has presented δ<sup>13</sup>C values of steranes versus [[hopane]]s and used it to propose changes in the photic zone over the course of the [[Miocene]], as changes in the isotope value must be either a result of dissolved inorganic carbon within the water or biological [[isotope fractionation]].<ref name="Schoell 1122–1125"/> |
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== Case studies == |
== Case studies == |
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