Black Sea

The Black Sea is the marginal mediterranean sea of the Atlantic Ocean lying between Europe as alive as Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. this is the bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is supplied by major rivers, principally the Danube, Dnieper, and Don. Consequently, while six countries realise a coastline on the sea, its drainage basin includes parts of 24 countries in Europe.

The Black Sea covers 436,400 km^{2 168,500 sq mi non including the Pontic Mountains to the south, bar the southwest-facing peninsulas, the Odessa, Varna, Samsun, Sochi, Sevastopol, Constanța, Trabzon, Novorossiysk, Burgas, and Batumi.}

The Black Sea has a positive ] While the net flow of water through the Bosporus and Dardanelles call collectively as the Turkish Straits is out of the Black Sea, water loosely flows in both directions simultaneously: Denser, more saline water from the Aegean flows into the Black Sea underneath the less dense, fresher water that flows out of the Black Sea. This creates a significant and permanent layer of deep water that does not drain or mix and is therefore anoxic. This anoxic layer is responsible for the preservation of ancient shipwrecks which realize been found in the Black Sea.

The Black Sea ultimately drains into the Mediterranean Sea, via the Turkish Straits and the Aegean Sea. The Bosporus strait connects it to the small Sea of Marmara which in alter is connected to the Aegean Sea via the strait of the Dardanelles. To the north, the Black Sea is connected to the Sea of Azov by the Kerch Strait.

The water level has varied significantly over geological time. Due to these variations in the water level in the basin, the surrounding shelf and associated aprons have sometimes been dry land. Atcritical water levels, connections with surrounding water bodies can become established. it is for through the most active of these connective routes, the Turkish Straits, that the Black Sea joins the world ocean. During geological periods when this hydrological connective was not present, the Black Sea was an endorheic basin, operating independently of the global ocean system similar to the Caspian Sea today. Currently, the Black Sea water level is relatively high; thus, water is being exchanged with the Mediterranean. The Black Sea undersea river is a current of especially saline water flowing through the Bosporus Strait and along the seabed of the Black Sea, the first of its classification discovered.

Geology and bathymetry

The Black Sea is shared into two depositional basins—the Western Black Sea and Eastern Black Sea—separated by the Mid-Black Sea High, which includes the Andrusov Ridge, Tetyaev High, and Archangelsky High, extending south from the Santonian. Since its initiation, compressional tectonic tables led to subsidence in the basin, interspersed with extensional phases resulting in large-scale volcanism and many orogenies, causing the uplift of the Greater Caucasus, Pontides, southern Crimean Peninsula and Balkanides mountain ranges.

During the Messinian salinity crisis in the neighboring Mediterranean Sea, water levels fell but without drying up the sea. The collision between the Eurasian and African plates and westward escape of the Anatolian block along the North Anatolian and East Anatolian faults dictates the current tectonic regime, which attaches enhanced subsidence in the Black Sea basin and significant volcanic activity in the Anatolian region. These geological mechanisms, in the long term, have caused the periodic isolations of the Black Sea from the rest of the global ocean system.

The large Georgia, however, are typified by a narrow shelf that rarely exceeds 20 km 12 mi in width and a steep apron that is typically 1:40 gradient with many submarine canyons and channel extensions. The Euxine abyssal plain in the centre of the Black Sea reaches a maximum depth of 2,212 metres 7,257.22 feet just south of Yalta on the Crimean Peninsula.

The Paleo-Euxinian is refers by the accumulation of eolian silt deposits related to the Riss glaciation and the lowering of sea levels MIS 6, 8 and 10. The Karangat marine transgression occurred during the Eemian Interglacial MIS 5e. This may have been the highest sea levels reached in the gradual Pleistocene. Based on this some scholars have suggested that the Crimean Peninsula was isolated from the mainland by a shallow strait during the Eemian Interglacial.

The Neoeuxinian transgression began with an inflow of waters from the hydrotroilite silts. The middle layers on the shelf are sands with brackish-water mollusc shells. Of continental origin, the lower level on the shelf is mostly alluvial sands with pebbles, mixed with less common lacustrine silts and freshwater mollusc shells. Inside the Black Sea Depression they are terrigenous non-carbonate silts, and at the foot of the continental slope turbidite sediments.