Danubius Delta , Delta Dunarii

Danubius Delta - details and images

Delta is limited to the southwest of Dobrogea Plateau, north forms the border with Ukraine and flows east into the Black Sea. Danube Delta is crossed by the parallel 45 ° N and longitude 29 ° longitude E. Delta deal with Razim - Sinoe 5050 km ², of which 732 km ² are in Ukraine, Delta Romanian recovered and a surface 2540 km ². Thanks to 67 million tons of silt to the Danube Delta increased annually by approx. 40 meters.

Danube Pătlăgeanca arrived at the fork into two branches, Chilia Tulcea branch north and south, which then arm in a salted Saint George divides arm in arm Sulina and St. George.

Chilia, forms the border with Ukraine, and transported over its length of 104 km ², 60% of Danube waters and alluvium.

Sulina branch is located in the middle Danube, and unlike de Chile, has a straight course, being constantly dredged to maintain navigation and maritime vessels. Has a length of 71 km and carries 18% of the Danube water.

During the arm of St. George is facing southeast, and is conducted on 112 km, carrying 22% of Danube flow. River islands formed at the beginning of delta Sacalin considered secondary.

Delta (except secondary delta Chilia arm) is traditionally part of the Dobrudja, but in antiquity and Middle Ages, the coast is much more to the west (between Chile and Murighiol Old Strabo's time, between Lake Dranov Periprava and the Byzantine era ), so that historical maps are including all Delta Dobrogea current geomorphological are false.

The Danube Delta is located, in geological terms, a mobile earth region called Danube Delta platform (predobrogeană region). Danube Delta platform comes into contact with the south-western North Dobrogea orogenetic by Oancea Fault-St. George, which is approximately parallel to the St. George arm.

Its geological structure consists of a crystalline foundation upon which ordering transgressively a sedimentary layer represented by a sequence of deposits Paleozoic, Triassic, Jurassic, Cretaceous, Neogene and Quaternary, derminate by sea and shallow drilling conducted in the area. Deposits of Paleozoic age, which are floors Silurian-Permian (438-230 million years), consisting of limestone, dolomite, Silt, lithic sandstones, with intercalations of tuffs vitroclastice.

Deposits of Triassic age (248-213 million years) are made on the basis of ferruginous Silt, clay, sandstone, microconglomerates, with intercalations of porfire feldspathic, and melafire Diabaz and transgressively appear dolomites, calcareous sandstones, Silt, marl AND . a. containing plant species (Striatoabietites sp., Ovalipollis ovalis etc.), foraminifera (Glomospirella sp., Spirillina sp. etc.), conodonde (Gondolella navicula, Gladiogondolella tethydis etc.).

Deposits of Jurassic age (ages Dogger-Malm - 176-142 million years) are composed mainly of limestone (the base), clays, limestone, sandstone, limestone and gray and yellow (on top), with fossil foraminifera ( Textularia Jurassic, Spirillina orbicula etc.), dinofagelate (Nannoceceratopsis spicula, N. pellucida, Ctenidodinium panneum etc.), etc.. Cretaceous deposits belonging floors Aptian-Senonian (121-65 million years) are composed mainly of clay and ferruginous Silt, with intercalations of fine sandstones and dolomites gipsifere, containing a low fitocenoză with Trilobosporilites apiverucatus, Clavifera Triplex etc..

Deposits of Neogene age (Sarmatian-Romanian floors - from 13.5 to 1.8 million years) are composed of a succession of layers with lumaşelice limestone, sand, Silt and clay, with Mactra sp., Sand, Silt and clay reddish with Dosinia maeotica, fine gray sand (with Dreissena rimestiensis, Limnocardium sp., Stylodacna orientalis and sands with sands with intercalations of clay, containing specimens bifarcinatus viviparus, etc. Dreissena polymorpha.

Quaternary age deposits (deltaic deposits belonging floors Pleistocene-Holocene - 1.8 to 0.01 million years) are formed, the base of a layer of red clay brick followed by a succession of layers of gravel, sand , Silt, clay and loess layers and on top of the home have fluviatilă alluvial and fluvial-lacustrine.
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