Tri- and tetracyclic terpanes as proxies for depositional environment reconstruction for weathered siliciclastics of Internal Dinarides Scientific paper

Abstract

This study examines the potential of using tri- and tetracyclic terpanes to determine the depositional environment of sediments lacking preserved fossils and whose biomarker distribution has been disrupted by biodegradation, weath­ering, or other alteration processes. In the case of sediments from Jazovnik, Sna­govo, Drina and Gučevo (Internal Dinarides), tricyclic terpanes have demonst­rated easy applicability and strong predictive power for distinguishing deposit­ional settings. This study analysed siliciclastic sediments exposed to prolonged chemical weathering, influencing the distribution of hydrocarbons, and resulting in highly abundant branched hydrocarbons and the presence of unresolved com­plex mixtures (UCMs). The abundances and interrelationships of tri- and tetra­cyclic terpanes (C₂₀–C₂₄TT, C₂₆TT, C₂₄TeT) showed valuable results. The triang­ular diagram incorporating C₂₀ + C₂₂%, C₂₁% and C₂₃% has proven particularly effective in distinguishing between swamp, fluvial-deltaic, freshwater lacustrine, and marine-saltwater lacustrine depositional environments. Once again, this method clearly depicts different sedimentary environments, providing valuable insights into the geological history of the studied area.