Development of the rift-type North Croatian Basin located in the south-western Neogene Pannonian Basin System and belonging to the Central Paratethys realm, was controlled by tectonics, climate, ...volcanic activity and eustatic fluctuations. The extrabasinal controls produced a succession of depositional environments from terrestrial to marine, and back to terrestrial, and the deposits form a large-scale transgressive-regressive cycle. Basin evolution is subdivided into the syn-rift phase which lasted from the Early Miocene (Ottnangian) until the Middle Miocene (middle Badenian), and in the post-rift phase from the Middle Miocene (late Badenian) to the Quaternary. These complex controls on deposition generated the opening and closing of connections to the open sea that occasionally resulted in the formation of unfossiliferous continental deposits, or generated the radiation of endemic species, such that it has been necessary to use regional Neogene stages for stratigraphic analysis of the Central Paratethys history. Earlier stratigraphic studies of the North Croatian Basin, that had been primarily based on biostratigraphy and superposition, were improved by recent results yielded from radiometric dating, and integrated biostratigraphy. They have been focused mainly on the Early/Middle Miocene and the Miocene/Pliocene boundaries that separate intervals of the specific depositional evolution of the basin. Most important depositional and palaeogeographic differences concern a relatively long period of development of the early continental phase that lasted from the Ottnangian to the early Badenian. In contrast to parts of the Pannonian Basin System characterized by marine deposition in the early Badenian, the NCB was characterized by long-lived fresh-water lacustrine deposition. The fresh-water Lake Slavonia that developed from the middle Pliocene to the early Pleistocene, indicates an independent phase of evolution of the south Pannonian Basin System, so the Cernikian regional stage was introduced for the lacustrine succession. Those stratigraphic and palaeogeographic differences additionally support the complexity of the Pannonian Basin System within the Central Paratethys realm supporting heterogeneous depositional development of continental rift-type basins.
•Development of the Neogene rift-type North Croatian Basin was strongly controlled by external factors.•First marine deposition commenced in the middle Badenian (early Middle Miocene) after a long-lasting continental phase.•Fresh-water Lake Slavonia developed from the middle Pliocene to the early Pleistocene.•Stratigraphic and palaeogeographic specifics support the complexity of development of the Pannonian Basin System.
A Középső-Paratethys üledékei elterjedtek Magyarországon, leggyakrabban a badeni (15,97–12,6 millió évvel ezelőtti) üledékekkel találkozhatunk. Az akkori sekélytengeri környezetek nagyon változatos ...élővilágnak nyújtottak otthont, köztük a tízlábú rákoknak, melyek maradványai gyakran megtalálhatók a badeni rétegeket feltáró lelőhelyeken. Magyarország régóta fontos szerepet játszik a kainozoós Decapoda kutatásban, elsősorban Lőrenthey Imre és Müller Pál gyűjteményének és kutatásának köszönhetően. Müller Pál rendkívül gazdag Decapoda gyűjteménye a 2015-ben bekövetkezett halála után akaratának megfelelően a Magyar Természettudományi Múzeumba került. Anyagának legjelentősebb részét a magyarországi badeni rétegekből gyűjtötte, és a példányok nagyrészt Budapestről, vagy Budapest környékéről származnak (Tétényi-fennsík, Diósd, Biatorbágy, Budafok, Rákos, Keresztúri út, Örs vezér tere, Kerepesi út, Gyakorló út, Thököly út, Mező Imre út = Fiumei út, Telepy utca). A Visegrádhegységből (Visegrád), a Börzsönyből (Nagymaros Törökmező, Zebegény, és Szob), és a Cserhátból (Mátraverebély, Szentkút és Sámsonháza) származó anyagok szintén jelentősek. A dunántúli badeni lelőhelyekről (Nyírád, Balatonakali-40, Kishajmás, Fertőrákos-21) viszont eddig nagyon kevés tízlábú rák maradványa került elő. Az eddigi vizsgálatok alapján csaknem száz Decapoda fajt lehetett elkülöníteni a magyarországi badeniben, a Gebiidea (1 faj), Axiidea (9 faj), Anomura (20 faj), és Brachyura (69 faj) alrendek képviselőiből. A fajok mindegyikét részletesen feldolgoztuk a közelmúltban megjelent monográfiában, revideált leírásokkal, elterjedési adatokkal, valamint fényképes ábrázolásokkal, különös tekintettel a típuspéldányokra. A 99 Decapodafaj rendszertani áttekintése mellett részletesen ismertettük azokat a magyarországi lelőhelyeket, ahol badeni tízlábú rák maradványok kerültek elő. A rendszertani leírások mellett határozókulcsot készítettünk valamennyi előkerült fajhoz (különkülön a carapax és az olló maradványokra). A taxonómiai vizsgálatok során az eddigitől eltérő genushoz soroltunk tíz fajt (új kombinációk), és számos faj esetében megállapítottuk, hogy azok megegyeznek korábban leírt fajokkal (szinonímák).
Eocene and Lower Oligocene rocks are potential source rocks for crude oil accumulations in the Hungarian Palaeogene Basin. To enhance the understanding of the hydrocarbon system, this study (i) ...assesses the petroleum potential of Palaeogene formations, (ii) characterises the source rock facies of the accumulated oils, and (iii) provides an oil-to-source correlation. Rock-Eval data of samples from three boreholes (W–1, W–9 and W–12) show that most Palaeogene formations are mature at depths exceeding 2.1–2.5 km. The coal-bearing Kosd Formation includes good to excellent gas- (and oil-) prone source rocks. The overlying Buda Marl Formation is typically organic matter-lean but contains oil-prone rocks with up to 2.3 wt% TOC and a fair petroleum potential in borehole W–9. The Tard Clay Formation in W–12 reaches up to 1.9 wt% TOC and shows HI values up to 440 mg HC/g TOC, characterising the deposits as good petroleum source rocks. Based on low TOC contents, the Kiscell Clay Formation is not considered a source rock. Molecular parameters of 12 crude oil samples indicate a shaly source rock deposited in a marine/brackish environment. Salinity stratification, causing the development of oxygen-depleted conditions, is likely. The organic matter is dominated by aquatic biomass, including algae, dinoflagellates and chemoautotrophic bacteria. Minor angiosperm-dominated organic matter was transported into the basin from the shoreline. Specific V-shaped compound-specific carbon isotope patterns of n-alkanes observed in crude oils and extracts from the Tard Clay prove the dominant source rock. Minor differences between biomarker ratios are related to vertical and lateral facies variations within the Tard Clay Formation. The accumulated oils are slightly more mature than the Tard Clay in borehole W–12.
•Eocene and Oligocene hydrocarbon generating sources in Hungarian Palaeogene Basin.•Molecular composition of accumulated crude oils indicates a shaly source rock.•Compound-specific carbon isotope determines the dominant source as Tard Clays.•V-shape isotope pattern is caused by chemoautotrophic bacterial activity.•Contributing source of the Buda Marls is assumable.
The middle Miocene foraminifera and ostracod record of the Central Paratethys usually reflects stable normal marine epositional environments for the Badenian and more patchy, less stable restricted ...marine environments for the Sarmatian. A 17 m thick outcrop at Pécs-Danitzpuszta, Mecsek Mts, SW Hungary exposed an upper Badenian to Pannonian succession where foraminifers and ostracods document significant environmental changes. The basal layers of the section contain micro- and macrofossils indicating normal marine, shallow, warm, well-oxygenated habitat with relatively high-energy conditions and algal vegetation on the bottom, and represent the upper Badenian (13.82 to 12.65 Ma). The marine deposits are followed by coarse sandstone, breccia and siltstone layers barren of microfossils but containing rhizoliths. The sediments were probably subaerially exposed for some time. The following marine inundation, marked by the appearance of clays and limestones as well as fossils, was dated to the late Sarmatian (ca. 12 to 11.6 Ma) on the basis of the restricted marine microfossil assemblages from the upper part of the succession (Porosononion granosum Zone, Aurila notata Zone). This community is characterized by exclusively eurytopic forms indicating an unstable and vegetated marginal marine environment with fluctuations in salinity, as well as oxygen and food availability. Within the 5 m thick upper Sarmatian marine interval, a unique fresh- to oligohaline fauna characterizes a few layers in less than 1 m thickness. This fauna consists of highly euryhaline foraminifera and freshwater to oligohaline ostracod assemblages, indicating a temporary salinity reduction to 5–10 ‰. No similar freshwater fauna has been reported from the Sarmatian of the Central Partethys so far. The eventual disappearance of the foraminifera from the paleontological record coupled with a complete turnover in the ostracod fauna indicates the transition from the marginal marine Sarmatian Sea to the brackish Lake Pannon, marking the Sarmatian/Pannonian boundary (11.6 Ma).
For the first time, a concise lithostratigraphic scheme for the lower and middle Miocene (Ottnangian – Badenian) of the northern and central Vienna Basin is proposed, which is based on the ...integration of core-material, well-log data and seismic information from OMV. For all formations and members type sections are proposed, geographic distribution and thickness are provided, typical depositional environments and fossils are described and age constraints are discussed. This time frame allows for a more reliable calculation of sedimentation rates. This in turn might be important for the reconstruction of the tectonic history of the Vienna Basin as we do not see fundamental differences between the piggy-back stage and the subsequent pull-apart regime. Following lithostratigraphic units are formalized herein and/or are newly introduced: Bockfließ Formation (Ottnangian), Aderklaa Formation, Gänserndorf Member and Schönkirchen Member (Karpatian), Baden Group, Rothneusiedl Formation and Mannsdorf Formation (lower Badenian), Auersthal Formation, Matzen Formation, Baden Formation, Leitha Formation (middle Badenian) and Rabensburg Formation (upper Badenian).
Stromatolitic carbonates of the Middle Miocene Oberpullendorf Basin (Austria) provide a great opportunity to study the evolution of microbial habitats under extreme environmental changes during the ...Badenian (Langhian and early Serravallian) Salinity Crisis. We here present the first geochemical data for Badenian stromatolites and show in a combined approach using major, trace element, and C – O isotope compositions obtained in individual stromatolitic carbonate laminae that short-term variations of palaeo-environmental conditions within the Oberpullendorf Basin coincide with individual microbialite morphologies.
The studied carbonates were affected by both detrital contamination and post-depositional alteration processes to different degrees. While fluid-mobile elements show clear evidence for post-depositional alteration processes, the rare earth element and yttrium (REY) as well as bio-essential element (Fe, Mn, Co, Zn, Mo, W) compositions of the carbonates remained unaffected. Stromatolitic carbonates that are devoid of detrital contamination (< 300 ppm Al) show typical shale-normalized seawater-like rare earth element and yttrium (REYSN) patterns with positive LaSN, GdSN anomalies, super-chondritic Y/Ho ratios, and heavy over light REYSN enrichments in the lower stromatolite units. These features suggest an open ocean seawater influenced depositional setting at the north-western margin of the Paratethys Sea. Stratigraphically upwards, pure stromatolitic carbonates show suppressed seawater-like REYSN signatures that argue for the development of a (semi)closed lagoon with restricted access to the open sea. Seawater-like REYSN patterns in the uppermost part resemble a reappearance of open marine environmental conditions. Interestingly, geochemical data of the upper part of the section contradict the ambient fossil record, showing the urge for future interdisciplinary approaches targeting the understanding and interplay of geochemistry, palaeontology, and geomicrobiology in modern and ancient microbial habitats. Enrichment factors of bio-essential trace elements that are either used as co-factors in metalloenzymes or metal-activated enzymes in biochemical reactions can be directly linked to the reconstructed environmental conditions: Sufficient element availability is ensured during marine conditions in the lower and uppermost stratigraphic sections; in contrast, continuous decreasing element availability of these elements is directly related to the temporary development of a (semi)closed lagoon.
•First geochemical data (C -O isotopes; Major & trace elements) of Badenian stromatolites.•Individual stromatolite layer reflect small-scale paleo-environmental evolution.•Short-term availability of bio-essential elements in different microbial habitats.
The reconstruction and interpretation of terrestrial ecosystems and vegetational patterns in the Central European Miocene have to take into account the influence of a vast landlocked water body, ...namely the Paratethys Sea. As a northern appendage of the early Mediterranean Sea, it spanned a north–south gradient of at least 4° latitude and has been suggested to represent some kind of “palaeothermometer”, which reflected slight expansions or restrictions of climatic belts. Due to its vulnerable marine connections it was also highly susceptible to major (global) sea-level fluctuations which are reflected in phases of endemism. Hence, a fairly continuous record of marine nearshore assemblages throughout the Miocene reflects an extraordinary interplay of sea-level fluctuations, changes in climate, immigrations, and blooms in autochthonous elements. Whilst biostratigraphic implications of these patterns were recognised early in palaeontology, a biogeographic model is still lacking. The intermingling of palaeogeographic terms with those restricted to biogeography is still commonly used — a situation which can be overcome by integrating data from different biota into a new palaeobiogeographic scheme.
Herein, a data-set of 1809 species-level taxa (Gastropoda and Foraminifera) serves as the base for interpretations. Gastropods in particular turned out to be of greatest value for the differentiation of palaeobiogeographic units due to sensitive reactions to all environmental parameters and occupying a wide range of ecological niches. Based on the excellent gastropod record the Proto-Danubian Province, Early Danubian P., Danubian P., Balatonian P. and a Proto-Caspian Subprovince are defined. The biogeographic reorganisations are associated with five major biotic events within the gastropod faunas. These “big five” comprise four extinctions – the late Ottnangian extinction event (LOEE), the mid-Badenian-extinction-event (MBEE), the Badenian–Sarmatian-extinction event (BSEE), the Sarmatian–Pannonian-extinction event (SPEE) – and one exceptional immigration/origination event termed the early Badenian Build-up event (EBBE).
Foraminifera are less valuable for palaeobiogeographic purposes in the area and time-slice studied. Endemisms are generally lower and turn-over rates less dramatic. They are, however, very useful for stratigraphic correlations with the Mediterranean and Atlantic areas. This fairly well calibrated marine biostratigraphy of the Central Paratethys serves as stratigraphic backbone and control for continental stratigraphy.
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.
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