Steroidal ketones in the early diagenetic transformations of Δ5 sterols in different types of sediments

Variation in the content and distribution of biomarkers in two closely situated peat and lignite deposits

“…In the past extract, only 5a-24-ethylcholestan-3-one was detected in trace amounts. Steroid ketones in geological samples may arise from direct input of living organisms and/or from microbial/chemical degradation of sterols , Nishimura, 1982Mermoud et al, 1984). As 5fl-homologs have not been detected in biological precursors of sedimentary organic matter (de Leeuw and Baas, 1986), direct inheritance from living organisms is indicated by the nearly exclusive presence of compounds with a 5~t-configuration, as are found in our samples.…”

Sedimentary lipid biogeochemistry of an hypereutrophic alkaline lagoon

“…The role of stanones as intermediates seems to be affected by the redox potential of the sedimentary system. In highly reducing environments the transformation has been observed to occur by direct conversion (MERMOUD et al, 1984). The Santa Olalla Lagoon sediments are likely one of these environments.…”

Assessment of lipid compounds and phosphorus in mangrove sediments of Santa Catarina Island, SC, Brazil

“…15 Cholesterol is of particular interest, not only because it is the main sterol commonly detected in sediments but also because it can generate another important sterol: coprostanol (5β-cholestan-3β-ol). Coprostanol and other stanols (ringsaturated sterols) are primarily microbial transformation products of sterols containing ∆ 5 double bonds, 17 or of steroidal ketone intermediates. 18 Stanols are an important component of particulate material.…”