Map of the Black Sea with bathymetry and surrounding relief

The Black Sea deluge is the best known of three hypothetical flood scenarios proposed for the Late

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...

history of the

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Roma ...

. It is one of the two of these flood scenarios which propose a rapid, even catastrophic, rise in sea level of the Black Sea during the Late Quaternary.Yanko-Hombach, V., Mudie, P., and Gilbert, A. S., 2011, ''Was the Black Sea catastrophically flooded during the post-glacial? Geological evidence and impacts'', in Benjamin, J. et al. (eds.), ''Underwater Archaeology and the Submerged Prehistory of Europe'': Oxbow Books, p. 245–262.

History

In 1997, William Ryan,

Walter Pitman Walter George Pitman (May 18, 1929 – June 12, 2018) was an educator and politician in Ontario, Canada. Background Born in Toronto, Ontario, he received a Bachelor of Arts in 1952 and a Master of Arts in 1954 from the University of Toronto. He ...

, Petko Dimitrov, and their colleagues first published the ''Black Sea deluge hypothesis''. They proposed that a catastrophic inflow of

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appro ...

into the Black Sea

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

occurred around 7600 years ago, . 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

Noah's flood The Genesis flood narrative (chapters 6–9 of the Book of Genesis) is the Hebrew version of the universal flood myth. It tells of God's decision to return the universe to its pre- creation state of watery chaos and remake it through the micro ...

. Some archaeologists support this theory as an explanation for the lack of

Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...

sites in northern Turkey. In 2003, Ryan and coauthors revised the dating of the early Holocene flood to 8800 years ago, . Before that date,

glacial A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...

meltwater Meltwater is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves over oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reducing. Meltwater can be ...

had turned the Black and

Caspian sea The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...

s into vast freshwater lakes draining into the

Aegean Sea The Aegean Sea ; tr, Ege Denizi (Greek language, Greek: Αιγαίο Πέλαγος: "Egéo Pélagos", Turkish language, Turkish: "Ege Denizi" or "Adalar Denizi") is an elongated embayment of the Mediterranean Sea between Europe and Asia. It ...

. 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 North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

. The levels of the lakes dropped through evaporation, while changes in worldwide

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...

caused global sea levels to rise. The rising

finally spilled over a rocky sill at the

Bosporus The Bosporus Strait (; grc, Βόσπορος ; tr, İstanbul Boğazı 'Istanbul strait', colloquially ''Boğaz'') or Bosphorus Strait is a natural strait and an internationally significant waterway located in Istanbul in northwestern T ...

. The event flooded of land and significantly expanded the Black Sea shoreline to the north and west. According to these researchers, of water poured through each day, two hundred times the flow of

Niagara Falls Niagara Falls () is a group of three waterfalls at the southern end of Niagara Gorge, spanning the border between the province of Ontario in Canada and the state of New York in the United States. The largest of the three is Horseshoe Falls, ...

. The Bosporus valley roared and surged at full spate for at least three hundred days. They argued that the catastrophic inflow of seawater resulted from an abrupt sea-level jump that accompanied the

Laurentide Ice Sheet The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square miles, including most of Canada and a large portion of the Northern United States, multiple times during the Quaternary glacial epochs, from 2.58 million years a ...

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 ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...

'' 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 Robert Duane Ballard (born June 30, 1942) is an American retired Navy officer and a professor of oceanography at the University of Rhode Island who is most noted for his work in underwater archaeology: maritime archaeology and archaeology of ...

identified what appeared to be ancient shorelines, freshwater snail shells, drowned river valleys, tool-worked timbers, and man-made structures in roughly of water off the Black Sea coast of modern Turkey.

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

YBP Before Present (BP) years, or "years before present", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Becau ...

, the level of the

Marmara Sea The Sea of Marmara,; grc, Προποντίς, Προποντίδα, Propontís, Propontída also known as the Marmara Sea, is an inland sea located entirely within the borders of Turkey. It connects the Black Sea to the Aegean Sea via the ...

would have risen high enough for two-way flow to start. The evidence used to support this scenario includes the disparate ages of

sapropel Sapropel (a contraction of ancient Greek words ''sapros'' and ''pelos'', meaning putrefaction and mud (or clay), respectively) is a term used in marine geology to describe dark-coloured sediments that are rich in organic matter. Organic carbon con ...

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.

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 brackish Neoeuxinian Lake, which occupied the Black Sea basin, was rapidly inundated by glacial meltwater overflow from the

Caspian Sea The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...

via the

Manych The Manych (russian: Маныч) is a river in the Black Sea–Caspian Steppe of Southern Russia. It flows through the western and central part of the Kuma–Manych Depression. In ancient times, it was known as the Lik. A tributary of the Don, it ...

Kerch Kerch ( uk, Керч; russian: Керчь, ; Old East Slavic: Кърчевъ; Ancient Greek: , ''Pantikápaion''; Medieval Greek: ''Bosporos''; crh, , ; tr, Kerç) is a city of regional significance on the Kerch Peninsula in the east of t ...

Spillway shortly after the

Late Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Eur ...

, about 17,000–14,000 BP. These extensive meltwater flooding events linked several

lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

and

marine water Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appr ...

bodies, starting with the southern edge of the Scandinavian and southward, through spillways to the Manych-Kerch and Bosphorus, 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.

Counter arguments

Criticisms of the deluge hypothesis focus on the magnitude and pace of the water level rise in the Black Sea. With enough moderation of these features, the catastrophe hypothesis is voided. However, a few key points should be noted: * Since the ending of the last glacial period, the global sea level has risen some . * The flood hypothesis hinges on the

geomorphology Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...

of the

Bosphorus The Bosporus Strait (; grc, Βόσπορος ; tr, İstanbul Boğazı 'Istanbul strait', colloquially ''Boğaz'') or Bosphorus Strait is a natural strait and an internationally significant waterway located in Istanbul in northwestern Tu ...

since the end of the glacial age. The Black Sea area has been sealed off and reconnected many times during the last 500,000 years. Opponents of the deluge hypothesis point to clues that water was flowing out of the Black Sea basin as late as 15,000 years ago. In this alternative scenario, much depends on the evolution of the Bosphorus. According to a study from 2001, the modern sill is below sea level and consists of Quaternary sand over-lying Paleozoic bedrock in which three sills are found at below sea level.

Sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...

on these sills started before 10,000 years ago and continued until 5,300 years ago. A large part of the academic geological community also continues to reject the idea that there could have been enough sustained long-term pressure by water from the Aegean to dig through a supposed isthmus at the present Bosphorus or enough of a difference in water levels (if at all) between the two water basins. In 2007, a research anthology on the topic was published which makes much of the earlier Russian research available in English for the first time and combines it with more recent scientific findings. According to a 2009 study by

Liviu Giosan Liviu Giosan is a Romanian and American marine geologist studying the interactions between climate, landscapes and humans. In the public sphere, he initiated "Ad Astra", an association of scientists from Romania and Romanian diaspora, and has b ...

, Florin Filip, and Stefan Constatinescu, the level in the Black Sea before the marine reconnection was below present sea level, rather than the (or lower) of the catastrophe theories. If the flood occurred at all, the sea level increase and the flooded area during the reconnection were significantly smaller than previously proposed. Since the depth of the Bosphorus, in its middle furrow, at present varies from , with an average depth of , a calculated

Stone Age The Stone Age was a broad prehistoric period during which stone was widely used to make tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years, and ended between 4,000 BC and 2,000 BC, with t ...

shoreline in the Black Sea lying lower than in the present day would imply that the contact with the Mediterranean might never have been broken during the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

, and hence there could have been no sudden waterfall-style transgression. The flooding could have been "not so big". In 2011, several authors concluded that "there is no underwater archaeological evidence to support any catastrophic submergence of prehistoric Black Sea settlements during the late Pleistocene or early Holocene intervals". A 2012 study based on

process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process, activities that produce a specific se ...

length variation of the dinoflagellate cyst ''Lingulodinium machaerophorum'' shows no evidence for catastrophic flooding. Geophysical, geochronological, and

geochemical Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...

evidence points to a "fast transgression" of the submergence lasting between 10 and 200 years.

History

Popular press accounts

Black Sea gradual inundation hypothesis

Late Pleistocene Great Flood hypothesis

Counter arguments

See also

References

Further reading

Further reading