On the origin of 24-norcholestanes and their use as age-diagnostic biomarkers

S Rampen, S Schouten, B Abbas, F Elda Panoto, G Muyzer, Christine Campbell, Johanna Fehling, J S Sinninghe Damste

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

24-norcholestanes have been shown to be useful biomarkers to assess the age of sediments and petroleum, but until now, the biological sources of their precursors, i.e., 24-norsterols, were unclear. We have unambiguously identified relatively high concentrations of 24-norcholesta5,22-dies-3 beta-ol in the diatom Thalassiosira aff. antarctica (6%-10% of total sterols) and, in much lower concentrations, in the dinoflagellate Gymnodinium simplex (0.2% of total sterols). These identifications and other reports of 24-norsterols in dinoflagellates suggest that both diatom and dinoflagellate species are major sources for 24-norcholestanes in sediments and petroleum. The evolutionary history of these organisms suggests that observed increases of 24-norcholestane concentration in the Jurassic and the Cretaceous are related to dinoflagellate expansion, whereas an increase in the Oligocene-Miocene is likely caused by diatom expansion. Our results also explain the biogeographical distribution of 24-norcholestanes, i.e., high concentrations at high (paleo)latitudes are likely caused by diatoms, while low concentrations at lower (paleo)latitudes are likely caused by dinoflagellates.
Original languageEnglish
Pages (from-to)419-422
Number of pages4
JournalGeology
Issue number5
DOIs
Publication statusPublished - 2007

Keywords

  • DIATOMS
  • SEA
  • STEROLS
  • IDENTIFICATION
  • Geology
  • SEDIMENTS
  • FOSSIL RECORD
  • DINOFLAGELLATE POLARELLA-GLACIALIS
  • OCEAN
  • TEMPERATURES
  • PHYTOPLANKTON

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