ABSTRACT: Source-indicating and maturity -related biomarkers from Miocene deposits from the Orava - Nowy Targ basin - preliminary results

The Orava-Nowy Targ basin is a structural basin filled with Tertiary and Quaternary terrigenous sediments, lying on eroded deposits of the Magura Nappe, Pieniny Klippen Belt and Podhale Paleogen Flysch. The aim of our work is to reconstruct sources of organic matter and depositional environments during middle and late Miocene in the Orava-Nowy Targ basin and to determine thermal maturity of the examined rocks. 11 samples from the western part of Orava-Nowy Targ basin were examined using GC-MS - 4 brown coals and 7 fine-grained clastic rocks with relatively high organic matter content. Preliminary results of biomarker analysis show that all samples are of terrigenous origin with a significant input of higher-plant derived organic matter and low maturity. Among n -alkanes, the long-chain homologues are found in significant amounts. Short-chain n -alkanes are almost absent, most probably due to water-washing of the samples. There is also a strong odd-over-even predominance, typical for land plant origin, with CPI values varying from 1.69 to 8.41. Tricyclic diterpenoids, indicators of conifers (cid:150) gymnosperms and their resins, are present in relatively low amounts with predominance of, depending on sample: pimarane, izopimarane, fichtelitene and abietane. Presence of tetracyclic diterpenoids like phyllocladane and kaurane indicates origin from leaf resins of e.g. Cupressaceae and Taxodiaceae what is consistent with palynological studies of these sediments. Steranes, sterenes