Fernenes and other triterpenoid hydrocarbons in Dicroidium-bearing Triassic mudstones and coals from South Australia

Abstract

Tandem sector mass spectrometry of the aliphatic hydrocarbon fraction of selected Late Triassic sub-bituminous coals, mudstones and plant fossils from the Leigh Creek coalfeld, Telford Basin, South Australia, has revealed three pseudohomologous series of triterpenoid hydrocarbons. Two of these series have been identified as fern-8-enes (C₂₉-C³¹) and fern-9(11)-enes (C₂₉-C³¹). The third series (C₂₉-C³¹) comprises saturated hydrocarbons tentatively identified as fernanes. These hydrocarbons appear to be related to pteridosperms (seed ferns) of the genus Dicroidium, fronds of which are preserved throughout the sedimentary sequence.