Naslov
Organic Geochemistry of Organic-Rich Cretaceous Carbonates of the Outer Dinarides (Dalmatia, South Croatia)

Autori
Španić, Darko ; Troskot-Čorbić, Tamara ; Stanković, Irenka ; Čuljak, Veronika

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
VI Isotope workshop of European Society for Isotope Research, Tallinn, Abstracts Book / - Talin : Institute of Geology at Tallinn Technical University, 2002, 105-105

ISBN
9985-50-346-5

Skup
VI Isotope workshop of European Society for Isotope Research

Mjesto i datum
Talin, Estonija, 29.06.2002. - 04.07.2002

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Cretaceous carbonates, Outer Dinarides, Dalmatia, source rock, bitumen, stable carbon isotope

Sažetak
The outcrop samples of the organic-rich Cretaceous carbonates from 20 localities in the Outer Dinarides (Dalmatia, South Croatia) were geochemically investigated. The objective of this study is detailed geochemical characterization of types of organic matter, their origin and genetic correlation as well as hydrocarbon potential. The results of the analyses show the presence of the kerogen type I-II in fine-grained, laminated limestones, which means the samples investigated are considered as source rocks of very high generative potential (Hi 660-810 mg HC/g TOC). Microscopic examinations of the kerogen revealed its amorphous appearance, without any traces of discrete organic components. Greyish-brown colour in transmitted light and bright green-yellow fluorescence indicates algal and bacterial origin of kerogen. Enrichment in heavy 13C isotope (d13CPDB -18 to -23‰) establish algal precursors of organic matter as well as anoxic deposition conditions. Some samples are dolomites and fosiliferous limestones with pores. Fissures and cavities filled with migrated bitumen. High content of sulphur and enrichment in 13C isotope (d13CPDB -22 to -25‰) as well as prominent n-C17 indicate that analysed bitumens originate from algal-derived kerogen and thus evidence their origin from organich-rich, laminated, fine-grained limestones. Those bitumens are product of the early generation from above mentioned source rocks. IN the absence of cap rock, bitumen was surface exposed, degraded and transformed from primary viscous liquid into solid bitumen.

Izvorni jezik
Engleski

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