A rising sea flood, the proposed and much-discussed refilling of the freshwater glacial Black Sea with water from the Aegean, has been described as "a violent rush of salt water into a depressed fresh-water lake in a single catastrophe that has been the inspiration for the flood mythology" (Ryan and Pitman, 1998). The marine incursion, caused by the rising level of the Mediterranean, apparently occurred around 7,600 years ago. It remains an active subject of debate among geologists, with subsequent evidence discovered to both support and refute the existence of the flood, while the theory that it is the basis of later flood myths is not proven.