Aliphatic and aromatic hydrocarbons in Candiota coal samples: novel series of bicyclic compounds

Aliphatic and aromatic fractions obtained from nine samples taken from two different seams of five boreholes in the Candiota coalfield (Lower Permian) were analysed by gas chromatography–mass spectrometry. The occurrence of the tetracyclic diterpenoids 16α(H)-phyllocladane and ent-16β(H)-kaurane among the aliphatic hydrocarbons, and the tricyclic diterpenoids simonellite and retene in the aromatic hydrocarbon concentrates, suggest an important input from conifers to the sedimentary biomass. This may explain the origin of a novel series of saturated and aromatic bicyclic compounds detected in the extracts which may be structurally related to the same precursor, possibly a conifer resin-derived tricyclic diterpenoid.