The genesis and evolution.
The country's youngest land, the Danube Delta has its origins according the scientists, 13 000 years ago. There are several phases in the forming of the Delta:
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Phase 1: It involves the existence of the Tulcea gulf. It used to be where the Delta lays right now and has stretched a lot upstream. Due to an impressing quantity of alluviums transported by the Danube and because of a very low flux, the conditions of forming a delta were formed in the gulf. You can see the original configuration in which the Babadac Gulf was very well contoured but it has later become the Razim lake.
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Phase 2: About 13 000 years ago, between the Caraorman and Letea islands, a littoral belt was formed and it closed the Tulcea Gulf transforming it into a lagoon. You can see in the picture the sand hills of Caraorman, which used to be part of the littoral belt also known as the initial belt.
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Phase 3: The clogging of the lagoon lead to the forming of a moore surface in which the Danube digged one of its oldest branches: Sf. Gheorghe. Aproximatively 9 000 years ago the alluviums transported by the Sf. Gheorghe made the Delta advance towards the Babadac Gulf.
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Phase 4: A new Danube branch has gone through the initial belt 7 000 years ago right where Crisan is today, and made some alluvial deposits at the end. This branch was called Sulina and had a quick advance towards the sea, due somehow to the clogging of the Sf. Gheorghe branch. Also in the north side of the Delta there's also a new branch which would help create the Delta, the Chilia branch.
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Phase 5: The clogging of the Sulina branch forces the water of the Danube to search for a new flow to the Black Sea, and in this way the initial sand belt has been gone through again in the north side 2 000 years ago where Periprava is today, forming Chilia branch. The alluvial deposits of the Chilia branch enhanced the advance of the Delta towards the north. Inside Delta the clogging of lakes and the forming of sand banks is a natural process that goes on nowadays, too.
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The first written testimonies on the Danube Delta come from Herodotus (484-425 B. C.) who wrote about the existence of 5 Danube branches.
Polybius (2nd century B.C.) write about 7 branches and many alluvial deposits at the mouth of the Istru.
The oldest map is a sketch drawn by Strabon (63 B.C.-19 A.D.) the most detailed description of the Delta, with its geographic coordinates too, came from Claudius Ptolemeus (90- 168 A.D.).
Beginning with the 15th century and up until the 18th, Dobrogea and the mouths of the Danube were in the custody of the Ottoman Empire.
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