Stable isotope geochemistry of different lithotypes of the Velenje lignite (Slovenia)

The stable isotope composition of carbon and nitrogen in low-rank coals is often used as a supplementary method to assess coal-forming processes in different paleoenvironments. In this study, carbon and nitrogen isotopes were investigated in different macroscopicvarieties i.e. lithotypes, of the Velenje lignite. δ13C and δ15N values were determined in 47 samples. The quantity and petrographical variability of the samples is considerably higher than in previous studies. δ15N characterization of the Velenje lignite is presentedin this paper for the first time. It was found that δ13C and δ15N values of different lignite lithotypes were influenced by original isotopic heterogeneity of the source plant ingredients,and by biogeochemical processes (gelification, mineralization of organic matter) at the early stage of biomass accumulation and its early diagenesis.