Sedimentary 12- n -Propylcholestanes, Molecular Fossils Diagnostic of Marine Algae

• Published in: Science
• Main Authors: Moldowan, J. Michael, Fago, Frederick J., Lee, Cathy Y., Jacobson, Stephen R., Watt, David S., Slougui, Nacer-Eddine, Jeganathan, Alwarsamy, Young, Donald C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 1990
• Subjects: Prudhoe Bay
• Online Access: http://dx.doi.org/10.1126/science.247.4940.309; https://www.science.org/doi/pdf/10.1126/science.247.4940.309

Certain C 30 -steranes have been used for identifying sedimentary rocks and crude oils derived from organic matter deposited in marine environments. Analysis of a C 30 -sterane from Prudhoe Bay oil indicates that these C 30 -steranes are 24- n -propylcholestanes that apparently are derived from precursor sterols 24- n -propylidene-cholesterols and 24- n -propylcholesterol. These widely occurring sterols are biochemically synthesized in modern oceans by members of an order (Sarcinochrysidales) of chrysophyte algae. These data thus imply that C 30 -sterane biomarkers in sedimentary rocks and crude oils have a marine origin. Screening of a few organic-rich sedimentary rocks and oils from throughout the Phanerozoic suggests that these C 30 -steranes first appeared and, therefore, their source algae evolved between Early Ordovician and Devonian.