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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Black Sea deluge hypothesis | 1/3 | https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis | reference | science, encyclopedia | 2026-05-05T09:59:07.496507+00:00 | kb-cron |
The Black Sea deluge is the best known of three hypothetical flood scenarios for the Late Quaternary history of the Black Sea that have been proposed since 1997. One other flood scenario proposes a rapid, even catastrophic, rise in sea level of the Black Sea. The maximum depth of the Bosporus and Dardanelles straits is 110 meters (360 ft) and 103 meters (338 ft), respectively, which would put them above the ocean levels in the Last Glacial Maximum, some 125 meters (410 ft) lower than in present times. The hypothesis is controversial, with other authors arguing for a more gradual inundation of the Black Sea.
== History ==
In 1997, William Ryan, Walter Pitman, Petko Dimitrov, and their colleagues first published the Black Sea deluge hypothesis. They proposed that a catastrophic inflow of Mediterranean seawater into the Black Sea freshwater lake occurred around 7,600 years ago, c. 5600 BCE. As proposed, the Early Holocene Black Sea flood scenario describes events that would have profoundly affected prehistoric settlement in Eastern Europe and adjacent parts of Asia and possibly was the basis of oral history concerning the myth of Noah's flood. Some archaeologists support this theory as an explanation for the lack of Neolithic sites in northern Turkey. In 2003, Ryan and coauthors revised the dating of the early Holocene flood to 8,800 years ago, c. 6800 BCE. Before that date, glacial meltwater had turned the Black and Caspian seas into vast freshwater lakes draining into the Aegean Sea. As glaciers retreated, some of the rivers emptying into the Black Sea declined in volume and changed course to drain into the North Sea. The levels of the lakes dropped through evaporation, while changes in worldwide hydrology caused global sea levels to rise. The rising Mediterranean finally spilled over a rocky sill at the Bosporus. The event flooded 100,000 km2 (39,000 sq mi) of land and significantly expanded the Black Sea shoreline to the north and west. According to these researchers, 50 km3 (10 cu mi) of water poured through each day. The Bosporus valley roared and surged at full spate for at least 300 days. They argued that the catastrophic inflow of seawater resulted from an abrupt sea-level jump that accompanied the Laurentide Ice Sheet collapse and the ensuing breach of a bedrock barrier in the Bosporus strait.
=== Popular press accounts === Popular discussion of this early Holocene Black Sea flood scenario was headlined in The New York Times in December 1996 and later published as a book. In a series of expeditions widely covered by mainstream media, a team of marine archaeologists led by Robert Ballard identified what appeared to be ancient shorelines, freshwater snail shells, drowned river valleys, tool-worked timbers, and man-made structures in roughly 100 metres (330 ft) of water off the Black Sea coast of modern Turkey.
== Late Pleistocene Great Flood hypothesis == In 2003 and 2007, a more ancient catastrophic flood scenario was proposed by Andrei L. Chepalyga for the Late Quaternary sea level rise of the Black Sea. The hypothesis for a "Late Pleistocene Great Flood" argues that a brackish Neoeuxinian Lake, which occupied the Black Sea basin, was rapidly inundated by glacial meltwater overflow from the Caspian Sea via the Manych-Kerch Spillway shortly after the Late Glacial Maximum, about 17,000–14,000 years ago. These extensive meltwater flooding events linked several lacustrine and marine water bodies, starting with the southern edge of the Scandinavian Peninsula and southward, through spillways to the Manych-Kerch and Bosporus, ultimately forming what has been referred to as the Cascade of Eurasian Basins. This event is argued to have caused a rapid, if not catastrophic, rise in the level of the Black Sea. It might have imposed substantial stresses upon contemporary human populations and remained in cultural memory as the Great Flood. The authors also suggested that the event might have stimulated the beginning of shipping and horse domestication.
== Black Sea gradual inundation hypothesis == In addition to the early Holocene "Noah's Flood" scenario proposed by Ryan, Pitman, Dimitrov, and their colleagues and the Caspian Sea overflow scenario of Chepalyga, the non-catastrophic progressive flood model (or gradual inflow model) has been proposed to explain the Late Quaternary sea level history of the Black Sea. About 8,000 years ago, the level of the Marmara Sea would have risen high enough for two-way flow to start. The evidence used to support this scenario includes the disparate ages of sapropel deposition in the eastern Mediterranean Sea and Black Sea; buried back-stepping barrier islands observed on the Black Sea shelf; and an under-water delta in the Marmara Sea, near the Bosporus Strait, composed of Black Sea sediments.