Abstract
The purpose of this letter is to put forward new interpretations of published data relating to ancient hypersaline environments.
Recent hypersaline environments are often characterized by high amounts of relatively uncommon sterols, such as Δ
7 sterols. The diagenetic pathway of such sterols, tentatively proposed here, might “rapidly” lead to formation of 20R- and 20S-5α(H),14β(H),17β(H)-steranes, providing such immature samples with a “mature appearance.” Extended 17α(H),21β(H)-hopanes and extended hop-17(21)-enes, present in ancient hypersaline environments, occur fully isomerized at C-22 and a diagenetic pathway explaining this phenomenon is proposed. The use of these specific stereoisomers as maturity parameters in the reconstruction of the thermal and burial history of sediments, could therefore lead to erroneous conclusions.