Stjepan Ćorić

Timing of the Middle Miocene Badenian Stage of the Central Paratethys

Abstract A new and precisely defined chronometric subdivision of the Badenian (Middle Miocene, regional stage of Central Paratethys) is proposed. This uses global events, mainly geomagnetic polarity reversals as correlated chronometric boundaries, supported by climatic and sea-level changes in addition to isotope events and biostratigraphic data. The Karpatian/ Badenian boundary lies at 16.303 Ma, at the top of Chron C5Cn.2n, which is near the base of the Praeorbulina sicana Lowest-occurrence Zone (LOZ). The Badenian/Sarmatian boundary is placed at the top of polarity Chron C5Ar.2n, thus at 12.829 Ma. In relation to three sea level cycles TB 2.3, TB 2.4 and TB 2.5 and astronomically confirmed data, the Badenian can be divided into three parts of nearly equivalent duration. The Early Badenian as newly defined here ranges from 16.303 to 15.032 Ma (top of polarity Chron C5Bn.2n). The younger boundary correlates roughly to the base of the planktonic foraminifera Orbulina suturalis LOZ at 15.10 Ma, the HO (Highest Occurrence) of the nannofossil Helicosphaera ampliaperta at 14.91 Ma (NN4/NN5 boundary) and the Lan2/Ser1 sequence boundary at 14.80 Ma. The subsequent Mid Badenian ranges from 15.032 Ma to 13.82 Ma; the latter datum correlates with the base of the Serravallian, characterized by a strong global cooling event reflected in the oxygen isotope event Mi3b. The main part of cycle TB 2.4 falls into the Mid Badenian, which can be subdivided by a short cooling event at 14.24 Ma during the Middle Miocene Climate Transition (14.70 to 13.82 Ma). The HCO (Highest common occurrence) of the nannofossil Helicosphaera waltrans at 14.357 Ma supports this division, also seen in the tropical plankton Zones M6 Orbulina suturalis LOZ and M7 Fohsella peripheroacuta LOZ that correspond roughly to the lower and upper Lagenidae zones in the Vienna Basin, respectively. The Late Badenian is delimited in time at the base to 13.82 Ma by the Langhian/Serravallian boundary and at the top by the top of polarity Chron C5Ar.2n at 12.829 Ma. The Mediterranean Langhian/Serravallian boundary can be equated with the Mid/Late Badenian boundary at 13.82 Ma. However, the Karpatian/Badenian boundary at 16.303 Ma, a significant event easily recognizable in biostratigraphy, paleoclimate evolution and sequence stratigraphy, cannot be equated with the proposed global Burdigalian/Langhian, and thus Early/Middle Miocene boundary, at 15.974 Ma

Revised Middle Miocene datum for initial marine flooding of North Croatian Basins (Pannonian Basin System, Central Paratethys)The Pannonian Basin System (PBS) originated during the Early Miocene as a result of extensional processes between the Alpine-Carp

The Pannonian Basin System (PBS) originated during the Early Miocene as a result of extensional processes between the Alpine-Carpathian and the Dinaride Orogenic Belts. The Paratethys Sea flooded the new basins successively during the Karpatian (late Burdigalian, Early Miocene) and the Early Badenian (middle Langhian, Middle Miocene). The North Croatian Basins (NCB) occupied the south-western margin of the PBS and the Central Paratethys Sea. Their initial marine flooding has until now been dated as Karpatian in age. The transgression into the NCB invaded a lacustrine environment therein, representing the northern prolongation of the vast Dinaride Lake System extending southwards as far as the Adriatic Plate. We reinvestigate two sections from opposite margins of the NBS - from Mt. Medvednica on the west and from Mt. Požeska on the east - including corresponding lowermost marine Miocene deposits to critically examine the Karpatian datum. Our new biostratigraphic data – integrating calcareous nannoplankton, planktic and benthic foraminifera, diatom and mollusk records – have substantially revised the previous interpretation. The presence of a calcareous nannoplankton assemblage of the NN5 Zone and the planktic and benthic foraminifera of the regional Lower Lagenidae Zone now place the transgression into the main Early Badenian transgressive pulse of the Central Paratethys. Consequently, the initial marine transgression correlates accurately with the middle part of the Early Badenian, which is more than 2 m.y. younger than the previously inferred datum and at least 1 m.y. younger than the lower boundary of the Badenian and the Middle Miocene, respectively. Finally, the basal lacustrine infill of the NCB, previously dated as Ottnangian (middle Burdigalian, Early Miocene) and continuously grading into marine deposits, has to be reconsidered as Early Badenian as well.

Lower and Middle Miocene biostratigraphy, Gulf of Suez, Egypt based on dinoflagellate cysts and calcareous nannofossils

This is the first detailed stratigraphic correlation of Lower and Middle Miocene deposits in the Gulf of Suez, Egypt using dinoflagellate cysts. The correlation is based on 273 ditch-cutting samples from five onshore boreholes located along the southwestern margin of the Gulf of Suez. The interval studied is represented by the Nukhul, Rudeis and Kareem formations of the Gharandal Group, and the lower part of the Belayim Formation of the Ras Malaab Group. These Miocene deposits unconformably overlie the Lower or lower Middle Eocene. The dinoflagellate cyst record is more diverse than previously reported and many taxa are documented for the first time in Egypt. Five biozones are established and tied to a chronostratigraphic framework by calibration to calcareous nannofossils (NN biozones) obtained from the same set of samples: (1) Lingulodinium machaerophorum Assemblage Biozone (GOSl), Aquitanian through mid-Burdigalian; (2) Exochosphaeridium insigne Taxon-range Biozone (GOS2), lower through mid-Burdigalian; (3) Apteodinium spiridoides Interval Biozone (GOS3), mid-Burdigalian through lower Langhian; (4) Cleistosphaeridium placacanthum Interval Biozone (GOS4), upper Burdigalian, Langhian, and lower Serravallian?); and (5) Polysphaeridium zoharyi Assemblage Biozone (GOS5), upper Langhian and Serravallian? Comparison with other Miocene biozonations from the Mediterranean, Central Paratethys, North Atlantic region, and eastern USA indicate that the highest occurrences of Apteodinium spiridoides, Cordosphaeridium cantharellus, Distatodinium paradoxum, Exochosphaeridium insigne and Cleistosphaeridium placacanthum, and the lowest occurrences of Exochosphaeridium insigne and Sumatradinium soucouyantiae are important datums, whereas the lowest occurrences of Hystrichosphaeropsis obscura, Labyrinthodinium truncatum, and Operculodinium? borgerholtense provide useful supporting age control.

Integrated high-resolution stratigraphy of a Middle to Late Miocene sedimentary sequence in the central part of the Vienna Basin

Integrated high-resolution stratigraphy of a Middle to Late Miocene sedimentary sequence in the central part of the Vienna Basin In order to determine the relative contributions of tectonics and eustasy to the sedimentary infill of the Vienna Basin a high-resolution stratigraphic record of a Middle to Late Miocene sedimentary sequence was established for a well (Spannberg-21) in the central part of the Vienna Basin. The well is located on an intrabasinal high, the Spannberg Ridge, a location that is relatively protected from local depocentre shifts. Downhole magnetostratigraphic measurements and biostratigraphical analysis form the basis for the chronostratigraphic framework. Temporal gaps in the sedimentary sequence were quantified from seismic data, well correlations and high-resolution electrical borehole images. Stratigraphic control with this integrated approach was good in the Sarmatian and Pannonian, but difficult in the Badenian. The resulting sedimentation rates show an increase towards the Upper Sarmatian from 0.43 m/kyr to > 1.2 m/kyr, followed by a decrease to relatively constant values around 0.3 m/kyr in the Pannonian. The sequence reflects the creation of accommodation space during the pull-apart phase of the basin and the subsequent slowing of the tectonic activity. The retreat of the Paratethys from the North Alpine Foreland Basin during the Early Sarmatian temporarily increased the influx of coarsergrained sediment, but eventually the basin acted mostly as a by-pass zone of sediment towards the Pannonian Basin. At a finer scale, the sequence exhibits correlations with global eustasy indicators, notably during the Sarmatian, the time of greatest basin subsidence and full connectivity with the Paratethyan system. In the Pannonian the eustatic signals become weaker due to an increased isolation of the Vienna Basin from Lake Pannon.

Stratigraphic re-evaluation of the stratotype for the regional Ottnangian stage (Central Paratethys, middle Burdigalian)

The Ottnangian stage represents the middle Burdigalian (c. 18.1-17.2 Ma) within the regional stratigraphic concept for the Central Paratethys. The section Ottnang-Schanze in the North Alpine Foreland Basin of Upper Austria has been defined as its stratotype by Rogl et al. (1973). We present an updated strati- graphic evaluation of the section based on biostratigraphy of foraminifers, dinoflagellate cysts and calcare- ous nannoplankton as well as magnetostratigraphy. In agreement with earlier studies, assemblages of benthic foraminifers (co-occurrence of Amphicoryna ott - nangensis and Sigmoilopsis ottnangensis, mass-occurrences of Lenticulina inornata) document a late early Ottnangian age. Dinoflagellate cyst Exochosphaeridium insigne is recorded for the first time in the early Ott- nangian and its occurrence together with Apteodinium spiridoides, Cordosphaeridium cantharellus and Glaphyrocysta reticulosa s. l. extends the regional dinoflagellate zone Ein from the middle to the early Ott - nangian. On a global scale, the revealed marker species indicate zone D17a (middle-late Burdigalian). Cal- careous nannoplankton assemblages with the very rare occurrence of Sphenolithus cf. belemnos and S. aff. heteromorphus show remarkable affinities to Mediterranean nannoplankton zone MNN3b. Together with the frequent occurrence of Helicosphaera ampliaperta and the absence of Triquetrorhabdulus carinatus an assignment to standard nannoplankton zone NN3 (early-middle Burdigalian) is indicated. Magnetostratigraphy revealed an inverse polarisation for the outcrop. In combination with the biostrati- graphic age constraints and the present correlation of the Ottnangian to the Bur3 sea-level cycle the section belongs to polarity chron C5Dr.2r. For the first time, an absolute age between 17.95-18.056 Ma for the stra- totype can be inferred.

Fish otoliths from the Konkian (Miocene, early Serravallian) of Mangyshlak (Kazakhstan): testimony to an early endemic evolution in the Eastern Paratethys

Reconstruction of fossil teleost faunas can provide important information on palaeoenvironments, palaeogeography and evolution, and otoliths are particularly useful for that purpose. Here we present an otolith-based fish fauna from the middle Miocene of the Eastern Paratethys, i.e. the Karagaily section of the Mangyshlak Peninsula in Western Kazakhstan, and report on the accompanying nannoplankton, foraminifera, molluscs and ostracods. A total of 30 teleost species are described and figured, including ten new species: Alosa paulicrenata n.sp., Morone? bannikovi n.sp., Centracanthus pobedinae n.sp., Genyonemus? karagiensis n.sp., Trewasciaenasuzini n.sp., Parablenniusprokofievi n.sp., Aphia djafarovae n.sp., Neogobius udovichenkoi n.sp., Ponticola zosimovichi n.sp., Pomatoschistus bunyatovi n.sp. Nannoplankton and gastropods indicate a Konkian (late Badenian, early Serravallian) age for this fish assemblage. The dominance of Gadidae and Gobiidae, together with the composition of the nannoplankton, indicates an inner-neritic to coastal environment with high productivity. The Konkian fish fauna of the Eastern Paratethys shows a high degree of autonomy relative to approximately contemporaneous fish faunas from the Central Paratethys and other European basins. This confirms that the Konkian was a time of limited faunal exchange between the Central and Eastern Paratethys, while a marine connection may have persisted between the Central Paratethys and the northern Mediterranean. We conclude that the fish fauna reported here records an early endemic development in the Eastern Paratethys during the middle Miocene (Konkian). The disappearance of Bregmacerotidae and Gonostomatidae (Bonapartia) during the preceding stage of the Karaganian and the first appearance of Palimphemus minusculoides in the Konkian are important biostratigraphical markers.KurzfassungDie Rekonstruktion fossiler Teleostei Faunen kann wichtige Erkenntnisse zur Paläoumwelt, Paläogeographie und Evolution liefern und Otolithen spielen hierfür eine besonders wichtige Rolle. In dieser Arbeit wird eine auf Otolithen basierende Fischfauna aus dem Mittel-Miozän der Östlichen Paratethys (Karagaily-Aufschluss, Mangyshlak Halbinsel, West-Kasachstan) vorgestellt und eine Übersicht über das begleitende Nannoplankton, Foraminiferen, Mollusken und Ostrakoden gegeben. 30 Teleostei-Arten werden beschrieben und abgebildet, darunter 10 neue Arten: Alosa paulicrenata n.sp., Morone? bannikovi n.sp., Centracanthus pobedinae n.sp., Genyonemus? karagiensis n.sp., Trewasciaenasuzini n.sp., Parablenniusprokofievi n.sp., Aphia djafarovae n.sp., Neogobius udovichenkoi n.sp., Ponticola zosimovichi n.sp., Pomatoschistus bunyatovi n.sp.. Auf der Basis des Nannoplankton und der Gastropoden ist die Fischgemeinschaft zeitlich in die Stufe des Konkium (spätes Badenium, frühes Serravallium) einzuordnen. Die dominierenden Gadiden und Gobiiden sowie die Zusammensetzung der Nannoplankton-Gemeinschaft lassen auf ein inner-neritisches bis küstennahes, nährstoffreiches und produktives Paläomilieu schließen. Insgesamt zeigt die Fischfauna des Konkium der Östlichen Paratethys einen hohen Anteil endemischer Arten im Vergleich zu gleichaltrigen Fischfaunen der Zentralen Paratethys und anderer Europäischer Becken. Dies bestätigt die Annahme eines begrenzten Faunenaustauschs zwischen der Östlichen und der Zentralen Paratethys zur Zeit des Mittel-Miozäns, während eine marine Verbindung zwischen der Zentralen Paratethys und dem nördlichen Mittelmeer offenbar weiterhin existierte. Die hier bearbeitete Fischfauna lässt weiterhin darauf schließen, dass die endemische Entwicklung der Östlichen Paratethys schon zu einem relativ frühen Zeitpunkt des Mittel-Miozäns (Konkium) begann. Das Verschwinden der Bregmacerotidae und Gonostomatidae (Bonapartia) in der vorherigen Stufe des Karaganium und das erste Auftreten von Palimphemus minusculoides im Konkium sind wichtige biostratigraphische Kriterien.

A GIANT EARLY MIOCENE SUNFISH FROM THE NORTH ALPINE FORELAND BASIN (AUSTRIA) AND ITS IMPLICATION FOR MOLID PHYLOGENY

ABSTRACT Three extraordinarily well-preserved skeletons and skeleton parts of an Early Miocene sunfish are described. These unique fossils allow a precise osteological description of one of the largest if not the largest sunfish (320 cm) known so far and represent one of the largest teleost fossils of the Cenozoic Era. This new sunfish genus is the sister-taxon of the extant Mola+Masturus clade and, together with these two genera, forms the sister-clade of Ranzania. The radiation of modern-type sunfishes therefore already had occurred during Oligocene times. The finding from the earliest Miocene narrows the gap between the oldest known Eocene primitive sunfish and the Middle and Upper Miocene records, which are all referable to extant genera. Austromola is introduced as a new genus of the family Molidae; Austromola angerhoferi is described as a new species.

A Middle Miocene endemic freshwater mollusc assemblage from an intramontane Alpine lake (Aflenz Basin, Eastern Alps, Austria)

The mollusc fauna of the early Middle Miocene (Langhian) intramontane Alpine Lake Groisenbach is described for the first time. The shells derive from the Feistring Formation in the Aflenz Basin in Austria, which was covered by Lake Groisenbach. The assemblage is moderately diverse with 12 gastropod and 2 bivalve species, suggesting shallow lacustrine and fluvial settings. Among the gastropods, only Theodoxus crenulatus (Klein, 1853) is known from other Miocene localities, whilst all other species are documented so far only from Lake Groisenbach. None of the Early and Middle Miocene lake systems of the Alpine-Carpathian Foredeep and the Balkan Peninsula displays any faunistic resemblance with this new fauna. Even coeval lake faunas from the close-by Graz Basin have no species in common with Lake Groisenbach. This pattern points to a surprising endemicity and biogeographic fragmentation in the Central European freshwater systems during the Early and Middle Miocene. The uniqueness of the newly described fauna is also indicated by the completely erratic occurrence of the otherwise African-Mediterranean genus Bulinus, which is unknown from all other central European Miocene freshwater systems. Emmericia roetzeli Harzhauser and Neubauer nov. sp., Nematurellazuschini Neubauer and Harzhauser nov. sp., Romania fastigata Neubauer and Harzhauser nov. sp., Odontohydrobia groisenbachensis Neubauer and Harzhauser nov. sp., Odontohydrobia pompatica Neubauer and Harzhauser nov. sp., Odontohydrobia styriaca Harzhauser and Neubauer nov. sp., Planorbis austroalpinus Harzhauser and Neubauer nov. sp., Gyraulus sachsenhoferi Harzhauser and Neubauer nov. sp., Bulinus corici Harzhauser and Neubauer nov. sp., Ferrissia crenellata Harzhauser and Neubauer nov. sp. and Stagnicola reinholdkunzi Harzhauser and Neubauer nov. sp. are introduced as new species.KurzfassungErstmals wird die Molluskenfauna des intramontanen alpinen Groisenbach-Sees aus dem frühen Mittel-Miozän (Langhium) beschrieben. Die Schalen stammen aus der Feistring-Formation des Aflenzer Beckens, in dem sich im mittleren Miozän der Groisenbach-See entwickelte. Die Vergesellschaftung ist mit 12 Gastropoden und 2 Bivalven Arten moderat divers und deutet auf seicht lakustrine und fluviatile Ablagerungsbedingungen. Unter den Gastropoden ist nur Theodoxus crenulatus (Klein, 1853) auch aus anderen miozänen Fundstellen bekannt, während alle anderen Arten bisher nur aus dem Groisenbach-See bekannt sind. Keines der früh- und mittelmiozänen Seen-Systeme der Alpen-Karpaten-Vortiefe und des Balkans zeigt faunistische Beziehungen zu der neuen Fauna. Selbst die gleichaltrigen Faunen des geographisch nahen Grazer Beckens weisen keine gemeinsamen Arten auf. Diese Muster deuten auf einen überraschend hohen Endemismus sowie auf eine starke biogeographische Fragmentierung der mitteleuropäischen Süßwassersysteme während des frühen und mittleren Miozäns. Die Einzigartigkeit der Fauna zeigt sich auch in dem erratischen Auftreten der ansonsten afrikanisch-mediterranen Gattung Bulinus, die aus keinem anderen miozänen See Mitteleuropas bekannt ist. Emmericia roetzeli Harzhauser und Neubauer nov. sp., Nematurella zuschini Neubauer und Harzhauser nov. sp., Romania fastigata Neubauer und Harzhauser nov. sp., Odontohydrobia groisenbachensis Neubauer und Harzhauser nov. sp., Odontohydrobia pompatica Neubauer und Harzhauser nov. sp., Odontohydrobia styriaca Harzhauser und Neubauer nov. sp., Planorbis austroalpinus Harzhauser und Neubauer nov. sp., Gyraulus sachsenhoferi Harzhauser und Neubauer nov. sp., Bulinus corici Harzhauser und Neubauer nov. sp., Ferrissia crenellata Harzhauser und Neubauer nov. sp., und Stagnicola reinholdkunzi Harzhauser und Neubauer nov. sp. werden als neue Arten eingeführt.

From biologically to hydrodynamically controlled carbonate production by tectonically induced paleogeographic rearrangement (Middle Miocene, Pannonian Basin)

The Leitha Mountains in Austria are a chain of hills separating the southern Vienna Basin and the Danube Basin. The Lower East Alpine basement of the Leitha Mts. is covered by Middle Miocene sediments of the Badenian and Sarmatian regional stages. Close to the northeastern margin of these hills, upper Badenian successions are exposed, which are part of a coralline algal-dominated carbonate platform with hydrodynamically influenced sediments. Six sections have been logged and subjected to detailed investigation and sampling. They are characterized by inclined beds (foresets), which have been formed by unidirectional transport of sediments. Large-scale asymmetrical ripples indicate strong currents affecting shallow topset deposits. Generally, this hydrodynamically controlled sedimentation, documented by seven facies types, is reflected in a strongly reduced diversity of facies and biota, contrary to the older facies-rich middle Badenian sediments. This change from biologically to hydrodynamically controlled sedimentation led to a reduction in diversity of facies and biota. Sediment transport, however, caused secondary mass occurrences of echinoids or foraminifers derived from seagrass meadows. This study unravels the distribution and differences of middle and upper Badenian deposits of the Leitha Mountains and the influence of tectonic activity. Changes in hydrodynamics on the Leitha Platform are linked to the formation of the Danube Basin starting in the middle Badenian when a new seaway to the southeast has started to form.

BIOSTRATIGRAPHY AND EVOLUTIONARY TENDENCIES OF EOCENE HETEROSTEGINES IN WESTERN AND CENTRAL CUBA BASED ON MORPHOMETRIC ANALYSES

Abstract: Megalospheric specimens of Heterostegina from four localities in Western and Central Cuba were morphometrically investigated using test characters, which are described by 15 growth-independent and growth-invariant attributes that enable complete test reconstruction in equatorial sections. The species Heterostegina cubana, H. ocalana, and Heterostegina sp. indet. were classified by nonmetric multidimensional scaling and cluster analysis. Discriminant analysis yielded significant separators between species such as the perimeter ratio of the first chamberlets, the decrease in chamberlet length from the previous spiral to the marginal side, the chamber height at the spiral side of the previous whorl, and the proloculus size. Based on a further discriminant analysis, specimens of H. ocalana from different localities, including specimens from Panama, are strongly separated by the number of operculinid chambers, the extension grade of the marginal spiral and the backward bend of chambers, documenting paleogeographic differences and apparent evolutionary trends such as the reduction of the number of operculinid chambers. In Cuba, Heterostegina is represented by H. cubana and Heterostegina sp. indet. in the Bartonian to lower Priabonian (calcareous nannofossil Zones NP 16-NP 17), while Heterostegina ocalana ranges from Priabonian (nannofossil Zones NP 17 to NP 19-20/CP 15) to probably lower Oligocene (Rupelian) in the lower and middle part of the planktic foraminiferal Zone O 1 (P 18) and in the middle part of the calcareous nannofossil Zone NP 21 (CP 16).