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GEOLOGICA CARPATHICA, 50, 4, BRATISLAVA, AUGUST1999339-349 MEDITERRANEAN AND PARATETHYS. FACTS AND HYPOTHESES OF AN OLIGOCENE TO MIOCENE PALEOGEOGRAPHY (SHORT OVERVIEW) FRED R GLNaturhistorisches Museum Wien, Burgring 7, A-1014 Wien, Austria (Manuscript received January 5, 1999; accepted in revised form March 17, 1999) Abstract: Paleogeographical considerations on the development of the Paratethys and the Mediterranean during Oligocene and Miocene are presented in twelve time-slices. Plate tectonic activities and the collision of India with Asia caused the destruction of the Western Tethys Ocean in the Late Eocene. The Mediterranean and the intracontinental Paratethys basins came into existence as new marine realms. In the Mediterranean Basin, open oceanic connections existed throughout the Oligocene and most of the Miocene. The Eastern Paratethys and Central to Western Paratethys showed different marine conditions and changing connections most of the time. A first period with reduced salinity, anoxic bottom conditions, and strong endemisms occurred throughout the Paratethys in a short period of the Lower Oligocene (Solenovian, NP 23). It was followed by more open marine conditions with widespread clastic sedimentation (Upper Kiscellian, Kalmykian, NP 24). By the collision of Africa and Arabia with Eurasia, the seaway between the Mediterranean Sea and the Indian Ocean was closed in Burdigalian time, but a new landbridge enabled distinct mammal migration between the continents (Gomphotherium Landbridge). During the Middle Miocene, marine sea-ways between the Indian Ocean, the Mediterranean, and the Paratethys opened and closed intermittently. Finally, the marine connections of the Paratethys were strongly reduced, giving way to endemic faunal development during the later Miocene (Sarmatian to Pontian). Key words: Oligocene, Miocene, Paratethys, Mediterranean, paleogeography. Introduction The past few years have seen a flood of new information on the paleogeography, paleobiogeography, and tectonic development of the circum-Mediterranean region during the later Cenozoic. This short overview is a result of some current publications (e.g., Rgl 1998) on the subject of continental and marine migrations and emphasizes the development of the Paratethys. The paleogeographical reconstructions must be regarded as only sketches that can help to explain migration possibilities; many parts raise more questions than they answer. The continent positions are based on the plate tectonic reconstructions of Scotese et al. (1988). Important information has been revealed by the recent paleogeographical studies of Hamor & Halmai (1988), Kovl et al. (1989), Boccaletti et al. (1990), Popov et al. (1993), Jones & Racey (1994), Goff et al. (1995), Jones & Simmons (1996), and Studencka et al. (1998). The most problematic period is the middle Miocene, with its rapidly changing paleobiogeographical conditions and strong tectonic activity. Only intensive investigations in the problematic tectonic regions from the southeastern end of the Carpathians, along the Balkanides to Northern Anatolia can solve some of the questions. Another problem is the different opinion in the correlation of stages between Central and Eastern Paratethys. The recent correlations are based on nannoplankton and planktonic foraminifers in comparison with the chronostratigraphic table of Berggren et al. (1995). A vanishing Tethys Ocean in the late Eocene Continents in motion, the dispersal of the Pangean continent, and the northward drift of India and Australia ended the period of the Mesozoic Tethys Ocean. These changes in the configuration of land and sea altered the pattern of oceanic circulations, the climate, and the faunal exchanges on the continents and in the sea. By the end of the Eocene, the Tethys Ocean had nearly vanished. A new Indian Ocean was born, and the western end of the Tethys was reduced to a Mediterranean Sea (Fig. 1). Europe was still an archipelago. Intercontinental seas covered large areas of the European platform and of western Asia. A mammal exchange between Asia and Europe was not possible. Between the stable Eurasian platform and the relics of the western Tethys, elongated deep basins had formed. North of India, a marine connection stretched to the West Pacific. An important connection of the Tethys with the Polar Sea existed via the Turgai Strait, on the far side of the Ural Mts. These seaways around Asia and the connections with the Polar Sea enabled warm-water exchanges and probably explain the sustained warm climate during the Late Eocene. Fig. 2. The birth of the Paratethys Sea. Tectonic activities along the Alpine front and the collision of India with Asia created the intercontinental Paratethys Sea, and south of the orogene the Mediterranean Sea. Continentalization increased, the Turgai Strait Ключевые слова: central paratethys, correlated, started, conference, sea, theparatethys, gl, existed, ottnangian, hung, migrate, stratigraphic correlation, formation, zone, foredeep, facts hypotheses, opened, hamr cid, transylvanian, land, cid glfig, paratethys, eocene, arabia, early, oligocene, place, indian ocean, strait, late, lake, gesell, transcaspian basin, giant pectinids, carpathian, period, publ, mitt, reduced salinity, event, east, paleogeography, plate, ocean, mediterranean paratethys, burdigalian, central, isolated, collision, popov, ofthe, dinarides, univ, early sarmatian, accompanied, europe, dry land, graben, facts, strong endemism, connection, west, condition, relic, seaway, carpathian foredeep, open, endemism, transylvanian basin, north sea, isolation, jones simmons, marine, slovenia, dr, observed, geol, realm, rotation, eastern paratethys, north, remained, simmons, rusu, inst, closed, late badenian, correlation, anatolia, bull, evolution, cid cid, corresponds, nn, oceanic, evaporite, basin, change, nannoplankton, neogene, abstracts, serravallian, thebase, alpine, fauna, mus, middle, wa, stratigr, miocene, np, time, upper, karpatian, indian, badenian, gontsharova, paratethys facts, cenozoic, tethys, jones, asia, africa, based, rom, pannonian, activity, reconstruction, increased, sarmatian, enabled, hypotheses, deep, western, eastern, pacific, regression, studencka, salinity, region, reduced, development, carpathians, india, endemic, marine realm, short, ann, northern anatolia, turgai strait, strong, continued, tectonic, soc, study, ser, mammal, middle miocene, mediterranean, base, closure, cid, area