Alkaline hydrolysis of kerogen from a Miocene lacustrine sediment (Nordlinger Ries, southern Germany) afforded a series of cembrenoid diterpenes characterized by a 14membered ring system together with a second, probably related, series of yet unidentified structure. This is the first report of the occurrence of these compounds in fossil organic matter. The interpretation of cembrenoids as molecular markers of arid or semiarid climate is consistent with other information about the depositional environment of the former Nordlinger Ries crater lake.
southern Germany. Structure assignments are based on comparison of mass spectra and relative gas chromatographic retention times with data obtained by gas chro-Polycyclic diterpenes have long been recognized as matography (GC) and gas chromatography/mass widely occurring constituents of many geological spectrometry (GC/MS) of a derivatized total extract of samples, e.g. coal, lignite, soils, sediments and pet-olibanum resin (frankincense) known to contain cemroleum. '-' ' The compounds are believed to derive brenes, and by interpretation of mass spectra.