Fritz Steininger

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.

European Neogene Marine/Continental Chronologic Correlations

An updated correlation is given of the revised Neogene European mammal chronology with the Neogene marine chronology and the magnetic polarity time scale.

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.

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.

Pacific neogene stratigraphy

The Fourth International Congress of Pacific Neogene Stratigraphy, was held July 29–31, 1987, at the University of California, Berkeley. This very successful congress was organized by the Regional Committee on Pacific Neogene Stratigraphy (RCPNS) of the International Union of Geological Sciences (IUGS) and the International Geological Correlation Program (IGCP) Project 246 “Pacific Neogene Events in Time and Space.” The meeting was attended by 180 scientists from 16 different countries, and more than 90 presentations were made, on topics ranging from paleoclimatology, biostratigraphy, regional stratigraphy and geologic history, new techniques in stratigraphy, evolutionary studies, and modern biofacies and sediment relationships. A. R. Edwards of the New Zealand Geological Survey (Lower Hutt, New Zealand) spoke on climatic events that he recognizes in the late Neogene strata of New Zealand. The carbon isotope shift during chron 6 (6.3–6.5 Ma) is identified in the sequence at Blind River (Marlborough, New Zealand). The extinction of ∼25% of New Zealand molluscan genera during the latest Micoene (Kapitean Stage) accompanied the greatly accelerated diversification of planktonic foraminifera lineages at this time. The New Zealand events are also coeval with the Messinian “salinity crisis” in the Mediterranean. A series of events (extinctions of Mollusca, appearance of glacial rock types, foraminifera speciation, and nannofossil appearances) in New Zealand late Pliocene rocks reflect the climatic deterioration. One type of sub-Antarctic molluscan fauna abruptly appeared in central North Island at 2.4 m.y., coeval with the onset of major Northern Hemisphere glaciation.