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

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 Gucevo (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.