Naslov
Paleoenvironmental dynamics in Southern Pannonian Basin during Middle Miocene marine flooding

Autori
Pezelj, Đurđica ; Mandic, Oleg ; Sremac, Jasenka

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

Izvornik
International Symposium on Foraminifera, Forams 2010 / - Bon, 2010, 159-159

Skup
International Symposium on Foraminifera, Forams 2010

Mjesto i datum
Bonn, Njemačka, 05.09.2010. - 10.09.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Middle Miocene; paleoenvironment; Pannonian Basin

Sažetak
Quantitative analysis has been carried out on 42 bulk sediment samples from the coal pit Ugljevik in NE Bosnia and Herzegovina. The outcrop displays the initial transgression of the Central Paratethys Sea in the southern Pannonian Basin. About 60 m thick section starts with Oligocene lacustrine deposits. Initial marine sediments superpose the angular disconformity. They bear assemblages of late Early Badenian Upper Lagenidae Ecozone passing upward into Middle Badenian Spirorutilus carinatus Ecozone, correlating thus with the late Langhian. Data distinguishing 84 benthic foraminifera species were processed by multivariate statistics. Results supported the definition of 5 upward gradually alternating assemblages. Hence the initial marine deposits comprise Cibicidoides ungerianus - Asterigerinata planorbis assemblage that inhabited high oxic environment of the inner shelf. Upward gradual deepening trend and ongoing transgression affected the increase in planctonic foraminifera contributions, the increase of infaunal and opportunistic benthic foraminifera species, and the decrease of bottom water oxygen content. Stable medium oxic conditions on middle to outer shelf install soon. They display the highly diversified Valvulineria complanata - C. ungerianus assemblage. The occasional organic matter input, triggering oxygen fluctuations along with the nutrient quantity and quality variation, is furthermore marked by alternations of V. complanata and V. complanata – Globocassidulina oblonga assemblages. Intensive lamination together with almost continuous presence of low oxic conditions indicates increase in organic matter input during Middle Badenian. The stratification in water column was possibly triggered by fresh water feed likely responsible for increased redeposition of shallow water species. Environmental stress is strongly suggested by increase of dominance and decrease of diversity recorded from Bulimina subulata - B. elongata - Valvulineria complanata - Bolivina dilatata assemblage. The studied marine flooding cycle shows pattern of initial upward deepening, followed by stabile high stand conditions. The small scale environmental disturbances recorded therein, turn than finally to continuously stressed low oxic bottom water conditions.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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