GeoActa Special Publication 1
2008
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GeoActa
an international Journal of Earth Sciences
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Dmitry A. Ruban
Department of Geology, University of Pretoria, Pretoria 0002, South Africa. Contact address: P.O. Box 7333, Rostov-na-Donu, 344056, Russian Federation. E-mail: ruban-d@mail.ru, ruban-d@rambler.ru
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Major Paleozoic-Mesozoic unconformities in the Greater Caucasus and their tectonic re-interpretation: a synthesis
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PDF (228 KB)
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Abstract
Four major unconformities are present within the Paleozoic-Mesozoic strata of the Greater Caucasus, a region that was derived from the Afro-Arabian margin of Gondwana during the Ludlow, then docked at the Laurussian margin near the European Alpine terranes, and moved eastwards during the Late Triassic-earliest Jurassic to occupy its present position. The Ordovician unconformity, which includes part of the Middle Ordovician, formed due to uncertain tectonic activity on the Gondwanan margin. The mid-Permian unconformity, which encompasses the Guadalupian to early Lopingian, might have resulted from the Saalian Orogeny accompanied with strike-slip activity. The Triassic/Jurassic unconformity, which encompasses the mid-Rhaetian to early Sinemurian, developed after the long-distance movement of the Greater Caucasus Terrane along a shear zone or, alternatively, after the global sea-level fall. These three mentioned major unconformities are correlated with similar unconformities in some European, north-central African, and Arabian basins. The mid-Jurassic unconformity, which encompasses the mid-Bathonian to the Early Callovian, might have been caused by arc-arc collision in the Caucasian sector of the northern Neotethys or by the major sinistral transtension from Europe to the Himalayas.
Keywords: Unconformity, Palaeotectonics, Paleozoic, Mesozoic, Greater Caucasus.
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