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Palaeoecology and sedimentology of the Miocene marine and terrestrial deposits in the “Medieval Quarry” on Devínska Kobyla Hill (Vienna Basin)

Pivko D., Hudáčková N., Hrabovský J., Sládek I., Ruman A.

Geological Quarterly

2017

Vol. 61, No. 3

549--568

Dramatic tectonic and sea level changes of the Central Paratethys realm during the Middle Miocene resulted in changes of the coastal and seabed morphology affecting the composition of the marine association and the distribution of the facies along the coast. Three different episodes (marine-terrestrial-marine) in the environmental evolution are interpreted. A lower marine unit (Badenian; Lower Serravallian) reflects organodetrital sedimentation on and around an algal bioherm. Low terrigenous input maërl facies of typical rhodalgal carbonate factory type characterise the top of the algal mound. On the slopes, a rim of rhodechfor facies separated the bioherm from the rest of the bottom which had a seagrass cover. This high-energy rhodechfor carbonate factory is described from the Central Paratethys realm for the first time. It is composed mostly of coralline algae (Mesophyllum, Lithothamnion, Spongites and Lithophyllum), benthic foraminifers (Elphidium crispum, Neoconorbina terquemi, Miniacina sp., Borelis melo), echinoids (cidaroid, spatangoid and diadematoid groups) and bryozoans. Uplift of the Malé Karpaty Mts. resulted in tectonic activity in the vicinity, documented by the presence of clastic dikes and normal faults in the profile studied. Subsequent fluvial and terrestrial sedimentation is represented by regolith, palaeosoil and channel body deposits set discordantly on the top of lagoonal deposits. Finally, the third episode is represented by the Sarmatian transgressive marine sequence, which is characterized by coarse pebbly deposit eroded from an uplifted pre-Neogene basement. The strata studied originated in a warm temperate climate around the Badenian–Sarmatian transition.

Evolution of depositional systems and sedimentary cycles in Želiezovce Depression of the Danube Basin

Rybar S., Sarinova K., Sujan M., Halasova E., Hudackova N., Zlinska A., Kovac M., Kovacova M., Ruman A., Ledvenyiova L

Geology, Geophysics and Environment

2015

Vol. 41, no. 1

129

Five deep wells (Pozba4, Pozba3, Dubnik1, Nová Vieska1, Modrany1), drilled in the Želiezovce depression of the south-east Danube Basin penetrate the Cenozoic sedimentary record in overall thickness ranging from 1000 m up to 3000 m. The total thickness gradually increases from South to the North. This area is well known for the complex geological structure related to the Central Western Carpathians and Transdanubian Range junction along the Hurbanovo – Diösjenö line. Many authors have studied this area in the past, nevertheless depositional systems, sedimentary cycles and the development of sedimentary facies were never understood in detail. The re-evaluation of biostratigraphy, paleoecology, sedimentology and the reinterpretation of e-logs were all incorporated into well correlations, what resulted in definition of four main sedimentary cycles: (1) the lowermost Oligocene cycle, consisting of mudstones with occasional sandstone intercalations, associated with slope to offshore marine environment. The age is supported by the presence of the NP 22 calcareous nannoplankton zone; (2) the transgressive Langhian (Lower Badenian) deposits, composed of mudstones with epiclastic volcanic material and tuffite beds were associated with nearshore to offshore environement. The age is supported by the NN4–NN5 calcareous nannoplankton zone; (3) the Serravallian (Upper Badenian-Sarmatian) cycle is composed mainly of mudstones with abundant Lithothamnium fragments associated with brackish, coastal pain environment. The age is confirmed by the NN6 calcareous nannoplankton zone and by the mass occurrence of fish scales and Ervilia dissita (Eichwald) bivalves; (4) the overlying strata represent the Tortonian-Pliocene (Pannonian-Pliocene) cycle. The strata consist mostly from claystone (lake environment) which is overlain by sandstone and siltstone layers (deltaic and alluvial plain environments). The Tortonian (Pannonian) age of the lowermost claystone is supported by finds of Dreissenidae bivalves. The Pliocene age is only inferred by superposition of the strata.