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

Abstract

A peat and two lignite samples taken from closely situated deposits in the Granada Basin (South Spain) were analysed for their lipid composition. Variations in the distributions and abundances of various compound classes including normal, branched and unsaturated fatty acids, aliphatic hydrocarbons, aliphatic and steroid alcohols and ketones, aldehydes, diterpenoids and triterpenoids suggest that a gradient in maturity exists among the samples indicating that the lignites were generally more mature than the peat. In spite of their similar rank, a different hopane distribution was observed between both lignite samples. Source materials include contributions from terrigenous (coniferous) higher plants as well as microbial sources. A possible contribution from marine phytoplankton can also be inferred in the lignite on the basis of the sterol distribution.