ASGP (2014), vol. 84: 259-279
EARLY BADENIAN TRANSGRESSION ON THE OUTER FLANK OF WESTERN CARPATHIAN FOREDEEP, HLUCHOV AREA, CZECH REPUBLIC
Šárka Hladilová (1), Slavomír Nehyba (2), Kamil Zágoršek (3), Pavla Tomanová Petrová (4), Maria Aleksandra Bitner (5) & Attila Demeny (6)
1) Department of Biology, Faculty of Education, Palacky University, Purkrabská 2, 771 46 Olomouc, Czech Republic; e-mail: sarka.hladilova at upol.cz
2) Institute of Geological Sciences, Faculty of Science, Masaryk University, Kotláøská 2, 611 37 Brno, Czech Republic; e-mail: slavek at sci.muni.cz
3) Department of Geography, Technical University of Liberec, Studentská 2, 461 17 Liberec, Czech Republic; e-mail: kamil.zagorsek at gmail.com
4) Czech Geological Survey, Leitnerova 22, 658 69 Brno, Czech Republic; e-mail: pavla.petrova at geology.cz
5) Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa, Poland; e-mail: bitner at twarda.pan.pl
6) Institute for Geological and Geochemical Research, RCSAES, Hungarian Academy of Sciences, Budaorsi ut 45, 1112 Budapest, Hungary; e-mail: demeny at geochem.hu
Hladilová, Š., Nehyba, S., Zágoršek, K., Tomanová Petrová, P., Bitner, M. A. & Demeny, A., 2014. Early Badenian transgression on the outer flank of Western Carpathian Foredeep, Hluchov area, Czech Republic. Annales Societatis Geologorum Poloniae, 84: 259–279.
Abstract: This multidisciplinary study, based on borehole cores from the Hluchov area in Czech Republic, documents an early Badenian marine transgression on the outer flank of the Western Carpathian Foredeep. The shallow-marine deposits represent coastal transgression over a terrestrial topography of weathered pre-Cenozoic bedrock. The lower facies association (FA1) consists of siliciclastic sediment derived from local substrate erosion. Facies indicate a wave-dominated environment with unstable bottom, variable rate of sediment supply and an incremental rise of relative sea level. The upper facies association (FA2) consists of carbonates indicating a major landward shift of shoreline, decline in siliciclastic input and further sea-level rise. The succession represents a transgressive to highstand systems tract.
The maximum flooding surface, ca. 1 m above the FA1/FA2 boundary, is signified by an anomalous decrease in K and Th, an increased Th/K ratio and highest U concentration. The heavy-mineral assemblages in FA1 confirm local sediment provenance, whereas those in FA2 indicate broader sediment derivation, including volcanic component from contemporaneous rhyolitic to rhyodacitic eruptions. The deposits contain a wide range of marine fauna, with the foraminifers and molluscs indicating an early Badenian age. Molluscs, bryozoans and echinoderms indicate a normal-salinity environment with a decreasing hydraulic energy. Foraminifers indicate salinity fluctuations in the lowest part of the succession. The isotopic composition of mollusc shells shows marked inter-species differences and a general negative shift in the δ13C and δ18O values, indicating diagenetic alteration. The impact of diagenetic processes appears to have been controlled by sedimentary facies. The highly negative δ13C and δ18O values correspond to sediment layers with the highest Th/K ratios and hence low clay content. Sediment permeability was thus probably crucial in controlling the differential circulation and impact of diagenetic fluids.
Manuscript received 11 January 2014, accepted 13 November 2014
