Fred Rögl

Paleogeography and palinspastic reconstruction of the Neogene of the Mediterranean and Paratethys

Summary Eight palaeogeographic-palinspastic sketches are presented for intervals from Late Oligocene to Pliocene times for the circum-Mediterranean area and the Paratethys. They are based primarily on accurate correlation of marine and continental biogeographic events and take into account the generally accepted ideas of plate tectonics. The marine and continental connections that can be inferred contribute important information on the geological evolution of the Eastern Mediterranean.

Land Mammal Distribution in the Mediterranean Neogene: A Consequence of Geokinematic and Climatic Events

European Neogene mammal ages are based on the evolution of different mammal groups and migrational events. The correlation of these mammal ages with the marine stages, the palinspastic reconstruction of circum-Mediterranean seas and seaways, and knowledge of continental and marine climates have allowed for a better understanding and timing of Neogene mammal faunal evolution. The most significant events influencing the faunal composition in the circum-Mediterranean area are discussed: the Oligocene-early Miocene Eurasian-African separation and the early Miocene Bering land-bridge connection; the Afro-Eurasian faunal exchange around 19 million years (m.y.); the early middle Miocene interruption of this Eurasian-African corridor; the Hipparion event in late Miocene-Tortonian time, and the generation of the Turolian circum-Mediterranean chronofauna in Messinian time. Pliocene to Pleistocene climatic oscillations and tectonic events finally shaped the Mediterranean mammal distribution of today, before the impact of mankind.

Systematic, stratigraphic, and paleoenvironmental contexts of first-appearing Hipparion in the Vienna Basin, Austria

ABSTRACT The tridactyl horse Hipparion (s.l.) has long attracted the attention of paleontologists and geologists alike for its potential use as a stratigraphic and paleoenvironmental index. A central dogma surrounding this horses record is that it first occurred abruptly and instantaneously throughout the Old World ca. 12.5 Ma, heralding a general late Miocene environmental shift from forest to savanna ecosystems. We present data on the oldest known Central European hipparions, “Hipparion” primigenium (s.s.), that bear on these issues. Our analysis of the local Vienna Basin stratigraphie sequence and Paratethys geochronology suggests that hipparions first provincial occurrence was ca. 11.0–11.5 Ma. We falsify the hypotheses of an Old World “Hipparion Datum” and the purported initial association of this horse with savanna habitats. An explicit cladistic analysis of “Hipparion” primigenium (s.s.), its North American sister taxon Cormohipparion occidentale, and several Old World primitive hipparions (“Grou...

A consideration of some major topics concerning Old WorldMiocene Mammalian chronology, migrations and paleogeography

Abstract The authors of this note met to discuss the chronology of certain Miocene biologic events and their implications concerning palaeogeographic reconstructions. Two topics in particular were examined. The first was that the collision of the Afro-Arabian Plate into mainland Asia appears to have had a gradual effect on the mammalian and marine faunas. The marine evidence suggests a progressive diminution in exchanges between the Mediterranean Sea and the Indian Ocean from the Chattian/Aquitanian boundary onwards (Adams et alii 1983) whereas the continental mammalian faunas do not indicate the occurrence of faunal interchanges prior to the Burdigalian. The period between 18 and 20 Ma seems to be the key moment for the establishment of intercontinental pathways permitting faunal exchanges between the two land masses. The second subject examined concerned the « Hipparion datum. Analysis of available geochronological evidence and biostratigraphical correlations do not confirm the date of 12.5 Ma attributed to the earliest known Mediterranean Hipparions. On the contrary, it seems that the radiometric dates obtained from tuffs at Howenegg (Germany) and Bou Hanifia (Algeria) on which this early date was founded, are not closely associated with the fossils they purport to date. New radiometric dates allied with magneto- and biostratigraphy allow us to suggest an age about 11.5 Ma to the earliest records of Hipparion in Europe and North Africa.

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.

Paleoproductivity of the northwestern Tethyan margin (Anthering section, Austria) across the Paleocene-Eocene transition

Sediments in the expanded Anthering Section at the northwestern Tethyan margin were deposited in an abyssal environment, at the continental rise to the south of the European plate. The section contains deposits from calcareous nannoplankton Zones NP9 and NP10 and displays the global negative carbon isotope excursion (CIE) in the upper part of Zone NP9. Associated with the CIE is a strong three-fold increase in the rate of hemipelagic sedimentation. This suggests an increased input of siliciclastic suspended material into the basin, which is indicative of enhanced continental runoff at that stratigraphic level. Concurrent acmes of siliceous plankton and dinoflagellate cysts indicate that a high input of dissolved nutrients affected even open marine settings and caused eutrophication of surface waters. The associated high flux of organic carbon to the seafloor resulted in oxygen-depleted conditions and caused the total extincton of benthic faunas. However, impoverished foraminifera faunas indicate that a change of ecological conditions started shortly before the CIE. 133 Egger, H., Fenner, J., Heilmann-Clausen, C, Rogl, F., Sachsenhofer, R.F., Schmitz. B., 2003, Paleoproductivity of the northwestern Tethyan margin (Anthering Section, Austria) across the Paleocene-Eocene transition, in Wing, S.L., Gingerich, P.D., Schmitz, B., and Thomas, E., eds., Causes and Consequences of Globally Warm Climates in the Early Paleogene: Boulder, Colorado, Geological Society of America Special Paper 369, p. 133–146.

Upwelling conditions in the Early Miocene Central Paratethys Sea

Upwelling conditions in the Early Miocene Central Paratethys Sea Evidence for regional upwelling conditions in the Central Paratethys Sea is presented for mid-Burdigalian (early Ottnangian) times. The oceanographic phenomenon is detected in clay-diatomite successions along the steep escarpment of the Bohemian Massif in the eastern North Alpine Foreland Basin. Interpretations are based on a multiproxy data-set including published sedimentological and paleontological data, newly performed stable isotope measurements (δ18O, δ13C) of foraminifers and bulk sediment samples, and analyses of dinoflagellate cyst assemblages. The revealed stable isotope values of planktonic foraminifers point to upwelling: low δ13C values indicate strong mixing of surface waters with rising nutrient-rich waters, high δ18O values reflect cool sea surface temperatures (SST). Temperature calculations give SSTs ranging from 10-14 °C. Cool SSTs and high productivity are additionally supported by bulk sediment analyses. Assemblages of dinoflagellate cysts indicate a distal-shelf environment with nutrient-rich waters. Westerly winds and tidal currents are discussed as potential driving forces behind the local upwelling event. As mid-Burdigalian geography favoured strong current patterns in the Central Paratethys as documented in the sedimentary record from the Rhône Basin to Hungary upwelling might have been a more common phenomenon in this epicontinental sea than currently known.

The missing link in the evolutionary origin of the foraminiferal genus Hantkenina and the problem of the lower-middle Eocene boundary

The initial appearance of the planktonic foraminiferal genus Hantkenina has been used for about fifty years to recognize the base of the Lutetian and middle Eocene. However, probably as a result of incomplete stratigraphic records, discrepant ranges of Hantkenina have been reported by various investigators at many Eocene sections. Here we report the first complete evolutionary transition from Clavigerinella to Hantkenina , from the northwestern Tethyan deep-water section at Holzhausl (Salzburg, Austria). A newly discovered species, Hantkenina nov. sp., is the link between Clavigerinella caucasica and Hantkenina mexicana . This finding unequivocally heralds the initial entry of Hantkenina , which is correlated to the upper part of calcareous nannoplankton Subzone NP15b ( Sullivania gigas Subzone), to be defined. This indicates a mismatch of ∼4.5 m.y. between the base of the Lutetian at the type locality, which has been placed within Subzone NP14b, and the first appearance datum of Hantkenina . Consequently, the first occurrence of Hantkenina can no longer be used as a marker for the base of the middle Eocene.

Paläotemperaturbestimmungen an aragonitschaligen mollusken aus dem alpinen mesozoikum

16O/18O-determinations were applied to aragonitic mollusks from the Alpine Mesozoic. Quantitative determinations of secondary reactions are only possible for animals with aragonitic shells. The secondary calcite content was determined by means of X-rays. The samples were prepared according to the method of McCrea (1950) and their 16O/18O ratios were measured by means of a double-focussing mass spectrometer with a double ion collector. Only a small number of these samples were suitable for temperature determinations. The determined values were graphically extrapolated to 0% calcite. Triassic (Ladinian and Karnian) samples indicated water temperatures of 17.0°–17.9°C for benthonic organisms. Nectonic forms from the Rhaetian showed temperatures of 21.0–30.2°C. It became evident that the temperature values are dependent on the water depth at which the animals were living. (Austroteuthis kuehniJel. and Zapfe: juvenile 30.2°C, adult 23.7°C). The deviation of the temperature determinations is about ±1.0°C. The palaeotemperature values are referred to a salinity of 34.7‰

Bolboforma (Phytoplankton Incertae Sedis), Bachmayerella and other Calciodinelloidea (Phytoplankton) from the Middle Miocene of the Alpine-Carpathian Foredeep (Central Paratethys)

Bolboforma is a microfossil of uncertain origin with affinities to protophytic algae. It generally occurs at high latitudes and/or in cool and temperate waters and has a high stratigraphic potential especially for the Miocene. Calcareous cysts of dinoflagellates represent the ‘benthic cyst stage’ of unicellular organisms belonging to the marine phytoplankton. The occurrence of Bolboforma, Bachmayerella is documented here and, for the first time, some calcareous cysts of dinoflagellates tentatively attributed to Alasphaera and Pithonella from Badenian (Langhian–Middle Miocene) sediments in Austrian and Moravian localities. Alasphaera and Pithonella were previously described from Cretaceous and Danian sediments only, therefore, their range has been extended into the Paratethyan Middle Miocene. Correlation of Bolboforma bioevents with standard geological time-scales allows confirmation, and in some cases refinement, of age assignments based on other microfossil groups, such as foraminifera and calcareous nannofossils, in Paratethyan areas. In particular, this paper presents a case study of the biostratigraphy of the Grund Formation outcropping at its type locality in Lower Austria. Age attribution of the Grund Formation has been uncertain for some time. The recovery of Praeorbulina glomerosa circularis and Uvigerina macrocarinata, associated with Bolboforma reticulata, allows the correlation of the Grund Formation with the Early Badenian (Middle Miocene). As planktonic foraminifera are generally very rare or absent in shelf deposits of many other Austrian and Moravian Middle Miocene sedimentary sequences, Bolboforma, and in particular B. reticulata, remains an important biomarker to identify lower Badenian sediments. Additionally, the new species Bolboforma gneixendorfensis Spezzaferri & Rögl is described. It is generally double-chambered with a weakly reticulate wall texture and is associated with Bolboforma reticulata, B. bireticulata and/or B. moravica.