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A plate-tectonics model of the Alpine evolution of the Caucasus is suggested. According to the model, in the Jurassic-Neocomian the Caucasian territory comprised the shelf of the East European platform, the marginal sea of the Great Caucasus, the Pontian-Transcaucasian island arc, the Anatolian-Minor Caucasian oceanic basin (Tethys) and the Iranian-Turkish microcontinent. Along the northern margin of the oceanic basin a convergent plate juncture extended. Part of the Caucasus, situated north of this plate boundary, represented the West Pacific-type active margin of the East European platform. In the Middle Cretaceous the Iranian-Turkish microcontinent collided with the Pontian-Transcaucasian island arc and as a result the Transcaucasian-Minor Asian continental block originated. In the central part of the latter an extensive Paleogene andesitic belt formed, with the Black Sea-Adjara-Trialetian and Talysh-South Caspian basaltic rift troughs on its rear (northern) side (incipient Black Sea and South Caspian basins). Major plate boundary shifted south, into the Zagros-Taurus basin, though the Anatolian-Minor Caucasian suture zone remained mobile in the Upper Cretaceous and Paleogene. From the Oligocene, under conditions of ongoing convergence of the Eurasian and Afro-Arabian continental blocks, the present-day intracontinental mountainous foldbelt has developed. 相似文献
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J. Agustí A. Vekua O. Oms D. Lordkipanidze M. Bukhsianidze G. Kiladze L. Rook 《Quaternary Science Reviews》2009,28(27-28):3275-3280
This article analyzes and discusses the chronological and zoogeographic context of the Pliocene site of Kvabebi in order to shed light into the background of the early human occupation of Eurasia, as evidenced by the early Pleistocene site of Dmanisi. New paleontological and paleomagnetic research has allowed this site to be placed in a reverse interval which can be identified as chron 2An.1r. The age of this site is therefore close to 3.07 Ma, coeval to the Hadar beds of the Afar Depression and slightly older than the last hipparionine faunas in Europe, such as Villarroya in Spain. The fauna of Kvabebi is composed of a number of species common to Europe and Asia, but also includes others with African affinities, such as Kvabebihyrax kachethicus, Protoryx heinrichi, Parastrepsiceros sokolovi and Gazella postmitilinii. However, the presence these species cannot be explained as the result of a Pliocene dispersal from Africa, but rather as the last remnants of the so-called Greek-Iranian province. 相似文献
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Erwan Messager Vincent Lebreton Laurent Marquer Elda Russo-Ermolli Ronan Orain Josette Renault-Miskovsky David Lordkipanidze Jackie Despriée Carlo Peretto Marta Arzarello 《Quaternary Science Reviews》2011,30(11-12):1439-1447
The present study focuses on new palaeobotanical data (pollen, phytoliths and fruits) from three of the oldest Early Palaeolithic sites in Eurasia (Dmanisi in Georgia, Ca’ Belvedere di Monte Poggiolo in Italy and Pont-de-Lavaud in France). The main aim is to examine the ecological factors associated with the first human dispersals out of Africa into Eurasia. The palaeoecological data are discussed with regards to chronology and geographical location of the settlements. The vegetation pattern of each site consists of temperate Eurasian and Mediterranean taxa, subtropical trees being more or less recorded depending on climatic and geographic features. The new palaeobotanical data show that different vegetation structures occurred between the first human dispersal in Caucasus and the later dispersals in western Eurasia. However, in all cases hominins seemed to be adapted to temperate ecosystems. In Caucasus, human occupation took place at 1.7 Ma in a forest-steppe environment, while at ca 1 Ma human populations occupied various settings such as open landscapes or dense forests. These data suggest that during the Early Pleistocene, human populations evolved and dispersed in western Eurasia, gradually increasing their degree of adaptation to diversified environments. 相似文献
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Tristan Garcia Gilbert Féraud Christophe Falguères Henry de Lumley Christian Perrenoud David Lordkipanidze 《Quaternary Geochronology》2010,5(4):443-451
Several hominid remains have been discovered in the open-air site of Dmanisi (Georgia), the oldest prehistoric site in Eurasia. Two major arguments prove that this site is close in age to the Plio-Pleistocene boundary: a Villafranchian fauna and the morphological characteristics of hominid remains recently ascribed to Homo georgicus. Direct dating of the lower hominid-bearing level was carried out on volcanic glass and minerals using the 40Ar/39Ar method. The concordant results from two different sampled locations allow the determination of the age of the earliest human presence in Eurasia. This radioisotopic result strengthens the argument that the first dispersal of hominids outside Africa occurred at least 1.8 Ma ago. 相似文献
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In this paper we review a number of scenarios which have been proposed to explain the first hominin “out of Africa” at the base of the Pleistocene. These are the brain expansion scenario, the cultural exclusion scenario, the migratory wave scenario and the common African home scenario. These scenarios are checked against the current evidence provided by the Georgian site of Dmanisi, which contains the oldest Eurasian hominins. Therefore, it is concluded that none of these scenarios fits with the existing evidence, and that the only real African influence in Dmanisi is restricted to early Homo itself. In order to explain the presence of early Homo at Dmanisi, it is concluded that the expansion out of Africa should have happened before the actual datum of Dmanisi, most probably linked to the spread of Mode 1 tools in Africa. 相似文献
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Sh.A. Adamia T. Chkhotua M. Kekelia M. Lordkipanidze I. Shavishvili G. Zakariadze 《Journal of Structural Geology》1981,3(4):437-447
The evolution of Tethys is analysed on the basis of ophiolitic geology, reconstruction of continental margins, and plate kinematics. The North Anatolian-Minor Caucasian-South Caspian ophiolitic belt is considered to be the major suture of Palaeozoic Tethys, dividing its southern carbonate shelf from the Pontian-Caucasian-Turanian active margin. The Caucasian part of the latter comprises the Transcaucasian island arc, the Great Caucasian small ocean basin, the Great Caucasian island arc and the Precaucasian marginal sea, each characterised by its own magmatic, metamorphic and sedimentary facies association typical of that tectonic environments. The North Anatolian branch of Tethys persisted throughout the Palaeozoic and Mesozoic, whereas eastwards the major oceanic tract shifted south into the Zagros zone.The Northern frame of Mesotethys comprises the Pontain-Caucasian and Nakhichevan-Iranian island arc systems, divided by the Minor Caucasian basin, a relict of Palaeotethys reduced to a narrow northern branch of the Mesozoic ocean. In the late Cretacaous-Palaeogene, the youngest southwestern branch of Tethys separated Taurus-Anatolia from the Arabian shelf. Its ‘old’ northern branches were closed in the Palaeogene. Northward subduction in the South Anatolia-Zagros intracontinental basin triggered Neogene calc-alkaline volcanism in the Pontides, Antolia, Caucasus and Iran. 相似文献
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Volcanic evolution of the interarc and marginal basins is analysed using the available data on volcanics from the presently existent and ancient back-arc basins of the western Pacific and Mediterranean. It is shown that in early (pre-spreading) stages of back-arc rifting, the character of volcanism is determined by “maturity” of the adjacent island arc. It is predominantly alkaline or mildly alkaline for back-arc basins related to the island-arcs with high-potash calc-alkaline and shoshonitic volcanism. The back-arc alkaline and mildly alkaline basalts strongly differ from the continental and oceanic rift volcanoes by constantly lower Ti, Nb and Zr contents. Because of these features these basalts are akin to the basaltic members of the island-arc volcanic series. As the latter, they are generally strongly enriched in K2O and LIL elements, whereas Na2O reveals comparatively small variability. With initiation of spreading a sharp depression of K2O, LIL and light REE occurs in the axial basalts of back-arc basins, that progressively approach the MORB composition. But even tholeiites from the most evolved basins that underwent a considerable spreading reveal slight but detectable geochemical peculiarities, indicating their island-arc affinities. Origin of the low-Ti alkaline basaltic magmas of the active continental margins is discussed. 相似文献
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