| Paratethys Sea ： ウィキペディア英語版|
The Paratethys ocean, Paratethys sea or just Paratethys was a large shallow sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia. The sea was formed during the Oxfordian stage of the Late Jurassic as an extension of the rift that formed the Central Atlantic Ocean and was isolated during the Oligocene epoch (about 34 million years ago). It was separated from the Tethys Ocean to the south by the formation of the Alps, Carpathians, Dinarides, Taurus and Elburz mountains. During its long existence the Paratethys was at times reconnected with the Tethys or its successors, the Mediterranean Sea or Indian Ocean. From the Pliocene epoch onward (after 5 million years ago), the Paratethys became progressively shallower. Today's Black Sea, Caspian Sea, Aral Sea and Lake Urmia are remnants of the Paratethys Sea.
==Name and research==
The name Paratethys was first used by V. D. Laskarev in 1924.〔; 1924: "Sur les equivalents du Sarmatien superieur en Serbie". In: Vujević, P. (ed.), ''Recueil de travaux offert à M. Jovan Cvijic par ses amis et collaborateurs''. Drzhavna Shtamparija, Beograd, pp. 73–85.〕 Laskarev's definition included only fossils and sedimentary strata from the sea of the Neogene system. This definition was later adjusted to also include the Oligocene series. The existence of a separated water body in these periods was deduced from fossil fauna (most importantly molluscs, fish and ostracods). In periods in which the Paratethys or parts of it were separated from each other or from other oceans, a separate fauna developed which is found in sedimentary deposits. In this way the paleogeographical development of the Paratethys can be studied.
Sedimentary strata from the Paratethys are difficult to correlate with those from other oceans or seas because at times it was totally separated from them. Stratigraphers of the Paratethys therefore have their own sets of stratigraphic stages which are still used as alternatives for the official geologic timescale of the ICS.
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