Extended 3β-alkyl steranes and 3-alkyl triaromatic steroids in crude oils and rock extracts

Jeremy Dahl*, J. Michael Moldowan, Roger E. Summons, Mark A. McCaffrey, Paul Lipton, D. S. Watt, Janet M. Hope

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    27 Citations (Scopus)


    In oils and Precambrian- to Miocene-age source rocks from varying depositional environments, we have conclusively identified several novel 3-alkyl sterane and triaromatic steroid series, including (1) 3β-n-pentyl steranes, (2) 3β-isopentyl steranes, (3) 3β-n-hexyl steranes, (4) 3β-n-heptyl steranes, (5) 3,4-dimethyl steranes, (6) 3β-butyl,4-methyl steranes, (7) triaromatic 3-n-pentyl steroids, and (8) triaromatic 3-isopentyl steroids. We have also tentatively identified additional homologs with 3-alkyl substituents as large as C11. The relative abundances of these compounds vary substantially between samples, as indicated by (1) the ratio of 3β-n-pentyl steranes to 3β-isopentyl steranes and (2) the ratio of 3-n-pentyl triaromatic steroids to 3-isopentyl triaromatic steroids. These data suggest possible utility for these parameters as tools for oil-source rock correlations and reconstruction of depositional environments. Although no 3-alkyl steroid natural products are currently known, several lines of evidence suggest that 3β-alkyl steroids result from bacterial side-chain additions to diagenetic Δ2-sterenes.

    Original languageEnglish
    Pages (from-to)3717-3729
    Number of pages13
    JournalGeochimica et Cosmochimica Acta
    Issue number18
    Publication statusPublished - 1995


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