Biostratigrafie spodní křídy manínské jednotky (lom Butkov, Strážovské vrchy, Západní Karpaty)

This paper is a continuation of systematic stratigraphical research of Lower Cretaceous sequence of the Manín Unit excavated in the Butkov quarry. Calcareous deposits are significant especially by richness of ammonites. Attention is focused on the parts enabling the definition of ammonite zones. The following ammonite zones were determined: the Campylotoxus Zone (Early Valanginian), the Furcillata Zone (Late Valanginian), the Balearis Zone (Late Hauterivian) and boundary between the Pulchella Zone and the Compresissima Zone (Early Barremian). Non-calcareous and calcareous dinoflagellates, calpionellids and calcareous nannoplankton were analysed in the same places to provide a correlation of their ranges with ammonite zones.Tato práce je pokračováním systematických stratigrafických výzkumů spodnokřídových uloženin manínské jednotky těžených v lomu Butkov. Tamější karbonátové uloženiny se vyznačují bohatým výskytem amonitů. Pozornost je věnována úsekům umožňujícím definování amonitových zón. Zjištěny byly následující amonitové zóny: zóna Campylotoxus (spodní valangin), zóna Furcillata (svrchní valangin), zóna Balearis (svrchní hauteriv) a hraniční uloženiny mezi zónou Pulchella a zónou Compressissima (spodní barrem). Ve stejných úsecích byly studovány vzorky na nevápnitá a vápnitá dinoflageláta, kalpionely a vápnitý nanoplankton za účelem jejich korelace s příslušnými amonitovými zónami

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

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 Re-interpretation of e-logs ware 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 what 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 ware associated with shelfall to offshore environement the age is supported by the NN4 - NN5 calcareous nannoplankton zone. (3) The Serravallian (Upper Badenian - Sarmatian) cycle is composed mainly by mudstones with abundant Lithothamnium fragments associated with brackish coastal pain environment, supported by the NN6 calcareous nannoplankton zone and by the mass occurrence of fish scales and  Ervilia dissita (Eichwald) bivalves. (4) The overlying strata are represent the Tortonian-Pliocene (Pannonian-Pliocene) cycle, consists mostly from claystone which are overlain by sandstone and siltstones layers is associated with lake, deltaic and alluvial plain environment. 

New reports of crab Styrioplax exiguus Glaessner, 1928 (Decapoda, Brachyura) from Miocene beds near Maribor, Slovenia

In this paper we report new specimens of an interesting Paratethyan decapod Styrioplax exiguus Glaessner, 1928, which extend the known palaeogeographic and stratigraphic distribution of the species. The described specimens originate from three different localities from Miocene beds in the Slovenske gorice, in the vicinity of Maribor. By analysing the fossil nannoplankton assemblages we were able to determine a Middle Miocene age of these deep water beds of the Central Paratethys

Lower Cretaceous succession and biostratigraphy near overthrust plane of Silesian Nappe (Ostravice River Channel, Outer Western Carpathians, Czech Republic)

Contact between the Upper Cretaceous rocks of the Subsilesian Nappe and the overthrust Lower Cretaceous rocks of the Silesian Nappe is uniquely exposed at locality Ostravice River Chanell. The deposits of the Silesian Nappe in the zone of overthrust plane that belong to the Hradiště Formation are tectonically affected. The more exact age of the mentioned rocks has never been documented earlier. The most significant stratigraphic data were obtained by the analysis of calcareous nannofossils. The sediments of the Hradiště Formation in the zone of overthrust of the Silesian Nappe belong to two partial tectonic slices. Sediments of slice on the contact between both the Nappes is, according to calcareous nannoplankton, of latest Hauterivian to Early Barremian age. In the area of the rapids, the other slice lying on it is of Late Hauterivian age. Micritic limestones occurring in the Late Hauterivian slice indicate basinal sedimentation above the carbonate dissolution level. Character of intercalated sandstones indicates of its turbiditic origin. Limestone interclasts in layers of gravelly sandstones document the erosion of the Upper Jurassic to early Lower Cretaceous carbonate platform by turbiditic currents. Further up the river, deposits belonging to higher, partial tectonic slices and stratal members of the Silesian Nappe were identified. At the beginning, a small part of the Veřovice Formation of Late Aptian age is exposed. After interruption, a huge outcrop of the Lhoty Formation of Middle and Late Albian age follows and then again the higher part of Hradiště Formation of Early Aptian age.Web of Science87240638

Biostratigraphy, sedimentology and paleoenvironments of the northern Danube Basin: Ratkovce 1 well case study

The Ratkovce 1 well, drilled in the Blatné depocenter of the northern Danube Basin penetrated the Miocene sedimentary record with a total thickness of 2000 m. Biostratigraphically, the NN4, NN5 and NN6 Zones of calcareous nannoplankton were documented; CPN7 and CPN8 foraminifer Zones (N9, 10, 11 of the global foraminiferal zonation; and MMi4a; MMi5 and MMi6 of the Mediterranean foraminiferal zonation were recognized. Sedimentology was based on description of well core material, and together with SP and RT logs, used to characterize paleoenvironmental conditions of the deposition. Five sedimentary facies were reconstructed: (1) fan-delta to onshore environment which developed during the Lower Badenian; (2) followed by the Lower Badenian proximal slope gravity currents sediments; (3) distal slope turbidites were deposited in the Lower and Upper Badenian; (4) at the very end of the Upper Badenian and during the Sarmatian a coastal plain of normal marine to brackish environment developed; (5) sedimentation finished with the Pannonian-Pliocene shallow lacustrine to alluvial plain deposits. The provenance analysis records that the sediment of the well-cores was derived from crystalline basement granitoides and gneisses and from the Permian to Lower Cretaceous sedimentary cover and nappe units of the Western Carpathians and the Eastern Alps. Moreover, the Lower Badenian volcanism was an important source of sediments in the lower part of the sequence

Integrated biostratigraphical, sedimentological and provenance analyses with implications for lithostratigraphic ranking: the Miocene Komjatice depression of the Danube Basin

The Komjatice depression, situated on the Danube Basin’s northern margin, represents a sub-basin of the Neogene epicontinental Central Paratethys Sea and Lake Pannon. The paper provides an insight into the character of sediment provenance evolution by study of well cores (ZM-1, IV-1, MOJ-1, VR-1 wells). A modern combination of provenance, sedimentology and biostratigraphy together with the reported redefinition of Pannonian formations resulted in a new lithostratigraphy of the study area. Moreover, newly published volcanic rock age data were used for calibration of biostratigraphy. The overall age span of the sedimentary fill is occupied only by late Badenian–Sarmatian (Serravallian) to Pannonian (Tortonian–Messinian) strata: 1) the basal alluvial sediments of the newly defined Zlaté Moravce Formation; 2) late Badenian–Sarmatian (Serravalian) marine sediments of the Vráble-Pozba Fm., connected with tectonic opening of the depression; 3) Pannonian (Tortonian) coarse grained sediments of the Nemčiňany Fm. with an erosional base; 4) Pannonian (Tortonian–Messinian) predominantly fine-grained, basin floor to slope Ivanka Fm., sandy deltaic Beladice Fm. and predominantly muddy, alluvial Volkovce Fm. In the middle Miocene provenance is situated in Paleozoic sequences and Neogene volcanic rocks occurring currently in the NE. During the late Miocene, provenance is changed to the NNW (Tribeč Mts.), although the transport from the NE also remained

Towards better correlation of the Central Paratethys regional time scale with the standard geological time scale of the Miocene Epoch

Depositional sequences originating in semi-enclosed basins with endemic biota, partly or completely isolated from the open ocean, frequently do not allow biostratigraphic correlations with the standard geological time scale (GTS). The Miocene stages of the Central Paratethys represent regional chronostratigraphic units that were defined in type sections mostly on the basis of biostratigraphic criteria. The lack of accurate dating makes correlation within and between basins of this area and at global scales difficult. Although new geochronological estimates increasingly constrain the age of stage boundaries in the Paratethys, such estimates can be misleading if they do not account for diachronous boundaries between lithostratigraphic formations and for forward smearing of first appearances of index species (Signor-Lipps effect), and if they are extrapolated to whole basins. Here, we argue that (1) geochronological estimates of stage boundaries need to be based on sections with high completeness and high sediment accumulation rates, and (2) that the boundaries should preferentially correspond to conditions with sufficient marine connectivity between the Paratethys and the open ocean. The differences between the timing of origination of a given species in the source area and timing of its immigration to the Paratethys basins should be minimized during such intervals. Here, we draw attention to the definition of the Central Paratethys regional time scale, its modifications, and its present-day validity. We suggest that the regional time scale should be adjusted so that stage boundaries reflect local and regional geodynamic processes as well as the opening and closing of marine gateways. The role of eustatic sea level changes and geodynamic processes in determining the gateway formation needs to be rigorously evaluated with geochronological data and spatially-explicit biostratigraphic data so that their effects can be disentangled

The stratigraphic and paleoenvironmental setting of Aptian OAE black shale deposits in the Pieniny Klippen Belt, Slovak Western Carpathians

During the Jurassic and Cretaceous, the Pieniny Klippen Belt units of the Outer Western Carpathians were situated on the edge of the Paleoeuropean shelf rimming the northermost margin of the Mediterranean Tethys. During the late early Aptian humid event, Lower Cretaceous pelagic carbonate (Maiolica) sedimentation was interrupted by terrigenous input as a consequence of the first major mid-Cretaceous climate perturbations. The fluctuation of radiolarian abundance indicated an expansion of the oxygen-minimum zone due to upwelling conditions and salinity changes. Foraminifera, radiolarians, non-calcareous dinocysts, and calcareous nannofossils encountered in the West Carpathian Rochovica section enable a comparison of the black shales of the upper lower Aptian Koňhora Formation with the well-known Selli Event. Subsequent anoxia patterns (depositional, productive, and stagnant) have taken part in the depositional regime. Early Aptian climate perturbations both in the Outer Western Carpathians, Swiss Prealps (situated in a similar position on the distal southern edge of the former Paleoeuropean shelf) and/or in other parts of the world are traceable with sedimentological, biological, and chemical proxies

Comments on the geology of the Crimean Peninsula and a reply to a recent publication on the Theodosia area by Arkadiev et al. (2019): "The calcareous nannofossils and magnetostratigraphic results from the Upper Tithonian-Berriasian of Feodosiya region (Eastern Crimea)"

International audienceHere we assess the evidence for the placing of magnetic and fossil biozonal boundaries in Upper Tithonian to Lower Berriasian (Jurassic–Cretaceous boundary) sedimentary rocks on the Black Sea coast south of Theodosia (Ukraine): that is, in magnetozones M19n to M17r. We consider our earlier-published results from these sections in relation to the correlative pattern that has become well established further west in Tethys. Additionally, this is compared and contrasted with other, alternative, results from Crimea that have been published in recent times

Sedimentary, biological and isotopic record of early Aptian paleoclimatic event in the Pieniny Klippen Belt, Slovak Western Carpathians

Orbital perturbations of Barremian/Aptian climate traceable by sedimentological, biological and chemical proxies have been studied in Mt. Rochovica (Western Carpathians, Pieniny Klippen Belt) sedimentary sequence. This pelagic carbonate sequence represents a record of sedimentation on a distal edge of the Paleoeuropean shelf. Pelagic carbonate deposition was influenced by clastic input from the elevated Czorsztyn Ridge (microbreccia of Tithonian/Berriasian limestones) and by fluxoturbidites derived from unknown carbonate buildups. Interruption of carbonate deposition by the terrigeneous Konhora Formation has been interpreted as a consequence of a humid event in the initial stage of the mid-Cretaceous Greenhouse climate. Three anoxia models (depositional, productivity and stagnant one) have been distinguished in the depositionary regime