Naslov
Organic petrology and geochemistry of the Oligocene source rocks in the Glina Depression (Croatia)

Autori
Španić, Darko ; Troskot-Čorbić, Tamara

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

Izvornik
65th Annual Meeting of the ICCP / Ciesielczuk, Justyna ; Fabianska, Monika ; Misz-Kennan, Magdalena ; Szopa, Krzysztof - Sosnowiec : University of Silesia, 2013, 118-118

ISBN
978-83-934-005-2

Skup
65th Annual Meeting of the ICCP

Mjesto i datum
Sosnowiec, Poljska, 25.08.2013. - 31.08.2013

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Organic petrology, Oligocene, Glina Depression

Sažetak
The outcrop samples from four locations of the Oligocene source rocks from Glina Depression in the Croatian part of Internal Dinarides were geochemically and petrologically analyzed and typified. Glina Depression occupies the southwestern portion of the Pannonian basin and is situated at its margin south from the petroleum productive Sava depression unit. External or Karst Dinarides represent carbonate platform which exists from the Jurassic to the Middle Eocene, while Internal Dinarides correspond to contemporaneous periplatform carbonate flysch interlayered with distal pelagic sediments of the Tethys Sea. At the Eocene-Oligocene boundary, plate tectonic activity caused destruction of the western part of the Tethys Sea, which resulted in the appearance of the Mediterranean Basin in the south and the intracontinental euxinic Paratethys Basin in the north. Present-day Internal Dinarides corresponds to southern margin of the Paratethys. Glina Depression was probably restricted lagoon with brackish influences and periodically suboxic to anoxic bottom conditions. Dark laminated carbonaceous shales have organic carbon in the range from 2.03 to 13.61 %. Rock Eval pyrolysis indicates kerogen type I-II with consequently good to excellent potential for hydrocarbon generation (HI= 331-946 mg HC/g TOC ; S2= 6.71-128.78 mg HC/g rock). Pyrolytic maturity parameters show diagenetic stage in thermal evolution (Tmax= 428-438°C, PI= 0.01-0.06). Microscopic examinations and stable carbon isotope analyses on kerogen concentrates, as well as gas chromatographic analyses of the alkane fraction of extractable organic matter revealed two types of organic facies: 1. Strong yellow fluorescing bituminite (amorphous organic matter) without any traces of structured macerals. Thermal alteration indices, estimated on isolated amorphous organic matter, are 2- (0.35-0.45 VR). Stable carbon isotope analyses give values from -28.61 to - 31.08 δ13CPDB. Gas chromatographic analyses show dominance of C18-C24 normal alkanes and Pr/Ph ratio <0.8, which is evidence for algal origin of organic matter and anoxic environment of deposition. 2. Moderate yellow-orange to orange-brown fluorescing bituminite with traces of yellow fluorescing alginite (Botryococcus), liptodetrinite and up to 20 % vitrinite (huminite). Vitrinite reflectance values are from 0.33-0.49 % VR. This type of kerogen is richer in heavy stable carbon isotope (-25.16 to -27.22 δ13CPDB) in comparison with former type of organic facies. In the gas chromatograms dominate odd alkanes in the range C25-C31 and Pr/Ph ratio is over 1, which means high terrestrial organic matter input and suboxic to oxic environment of deposition.

Izvorni jezik
Engleski

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