structural:expansion, information:extraction, stylistic:tone
Formation

The exact cause and date of the formation of the Bosporus remain a subject of debate among geologists. One recent hypothesis, dubbed the Black Sea deluge hypothesis, which was launched by a study of the same name in 1997 by two scientists from Columbia University, postulates that the Bosporus was flooded around 5600 BCE (revised to 6800 BCE in 2003) when the rising waters of the Mediterranean Sea and the Sea of Marmara broke through to the Black Sea, which at the time, according to the hypothesis, was a low-lying body of fresh water.

Many geologists, however, claim that the strait is much older, even if relatively young on a geologic timescale.