Naslov
Middle Miocene benthic foraminiferal communities and their response to shallowing-upward trends - example from Croatia

Autori
Pezelj, Đurđica ; Sremac, Jasenka ; Bermanec, Vladimir

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

Izvornik
International Symposium on Foraminifera FORAMS 2014, Chile, 19-24 January 2014. Abstract Volume / Marchant, Margarita ; Hromic, Tatiana - Concepcion : University of Concepcion ; University of Magallanes, 2014, 115-116

ISBN
978-83-88927-35-5

Skup
International Symposium on Foraminifera FORAMS 2014

Mjesto i datum
Concepción, Čile, 19.01.2014. - 24.01.2014

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
Foraminifera; Palaeoecologa; Middle Miocene; Croatia

Sažetak
During the Middle Miocene, Northern Croatian Medvednica Mt. was an island within the Pannonian Basin, situated at the SW margin of the Central Paratethys Sea. Shallow marine Badenian sedimentary rocks from the SW slopes of Medvednica Mt. reflect a transgressive-regressive cycle with emersion during the late Middle Miocene, in concordance with the global sea-level change. Regression reflects itself in different sedimentary patterns and distribution of biota in the upper part of studied sections in SW Medvednica Mt. In marginal shoal area (Borovnjak locality) variations in salinity are prominent, resulting with brackish conditions at the Badenian/Sarmatian boundary. Tolerant biota typical for such conditions, are defined as Ammonia–Elphidium community. Deeper and more sheltered environment of Gornje Vrapče reflects regressive trends in cyclic lamination. Laminae differ in colour, calcium content and foraminiferal communities (Heterolepa–Bolivina community/Bolivina–Cassidulina community/Elphidium–Asterigerinata community). The uppermost part of the section is represented with coralgal biolitite, and, finally, emersion between the Upper Badenian and Lower Sarmatian deposits (equivalent of Middle Serravalian Mediterranean substage). Dominant controlling factors of foraminiferal communities in laminated part of section were fluctuations in bottom oxygen content (BFOI 54.75–93.94), and changes in quantity and quality of food supply. Possible causes can be significant periodical input of terrestrial material and/or seasonal oxygen depletion at the sea bottom.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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