title: Sedimentary 12-n-Propylcholestanes, Molecular Fossils Diagnostic of Marine Algae.
abstract: 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.
authors.forename: J M
authors.initials: JM
authors.lastname: Moldowan
authors.forename: F J
authors.initials: FJ
authors.lastname: Fago
authors.forename: C Y
authors.initials: CY
authors.lastname: Lee
authors.forename: S R
authors.initials: SR
authors.lastname: Jacobson
authors.forename: D S
authors.initials: DS
authors.lastname: Watt
authors.forename: N E
authors.initials: NE
authors.lastname: Slougui
authors.forename: A
authors.initials: A
authors.lastname: Jeganathan
authors.forename: D C
authors.initials: DC
authors.lastname: Young