Black Sea deluge theory
Encyclopedia
The Black Sea deluge is a hypothesized catastrophic rise in the level of the Black Sea
circa 5600 BC due to waters from the Mediterranean Sea
breaching a sill in the Bosporus
Strait. The hypothesis made headlines when The New York Times
published it in December 1996, shortly before it was published in an academic journal. While it is agreed that the sequence of events described did occur, there is debate over the suddenness, dating and magnitude of the events. Two opposing hypotheses have arisen to explain the rise of the Black Sea: gradual, and oscillating. The oscillating hypothesis specifies that over the last 30,000 years, water has intermittently flowed back and forth between the Black Sea and the Aegean Sea
in relatively small magnitudes, and does not necessarily presuppose that there occurred any sudden "refilling" events.
In 1997, William Ryan and Walter Pitman published evidence that a massive flooding of the Black Sea occurred about 5600 BC through the Bosporus
, following this scenario. Before that date, glacial
meltwater had turned the Black and Caspian
Seas into vast freshwater lakes draining into the Aegean Sea
. As glacier
s 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 sea level to rise. The rising Mediterranean finally spilled over a rocky sill at the Bosporus. The event flooded 155000 km² (59,845.8 sq mi) of land and significantly expanded the Black Sea shoreline to the north and west. According to the researchers, "40 km³ (9.6 cu mi) of water poured through each day, two hundred times what flows over Niagara Falls
... The Bosporus flume
roared and surged at full spate for at least three hundred days."
Samplings of sediments in the Black Sea by a series of expeditions carried out between 1998 to 2005 in the frame of a European Project ASSEMBLAGE and coordinated by a French oceanographer, Gilles Lericolais, brought some new inputs to the Ryan and Pitman's hypothesis. These results were also completed by the Noah project led by the Bulgarian Institute of Oceanography (IO-BAS). Furthermore, calculations made by Mark Siddall predicted an underwater canyon that was actually found.
Countering the hypothesis of Ryan and Pitman are data collected prior to its publication by Ukrainian
and Russia
n scientists including Valentina Yanko-Hombach, who claims that the water flow through the Bosporus repeatedly reversed direction over geological time depending on fluctuation in the levels of the Aegean Sea and the Black Sea. This contradicts the hypothesized catastrophic breakage of a Bosporus sill. Likewise, the water levels calculated by Yanko-Hombach differed widely from those hypothesized by Ryan and Pitman.
In 2007, a research anthology on the topic was published which makes available much of the earlier Russian research in English for the first time, and combines it with more recent scientific findings.
A five-year cross-disciplinary research project under the sponsorship of UNESCO
and the International Union of Geological Sciences
was conducted 2005–9.
A February 2009 article reported that the flooding might have been "quite mild".
According to a study by Giosan et al., the level in the Black Sea before the marine reconnection was 30 m below present sea level, rather than the 80 m, 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. It also occurred earlier than initially surmised, ca. 7400 BC, rather than the originally proposed 5600 BC. Since the depth of the Bosphorus, in its middle furrow, at present varies from 36 to 124 m, with an average depth of 65 m, a calculated stone age shoreline in the Black Sea lying 30 m lower than in the present day would imply that the contact with the Mediterranean may never have been broken during the Holocene
, and hence that there could have been no sudden waterfall-style transgression.
Although neolithic
agriculture had by that time already reached the Pannonian plain, Ryan and Pittman link its spread with people displaced by the postulated flood. More recent examinations by oceanographers such as Teofilo A. "Jun" Abrajano Jr. at Rensselaer Polytechnic Institute
and his Canadian colleague Ali Aksu of the Memorial University of Newfoundland
have cast some doubt on this linkage. Abrajano's team, finding sapropel
mud deposits in the Sea of Marmara
which are today associated with freshwater outflow over top of salt-water inflow, have concluded that there has been sustained fresh water outflow from the Black Sea to the Mediterranean for at least 10,000 years. In 2003, Michael Sperling concluded that the Black Sea was not a major freshwater source contributing to formation of the Marmara Sapropel S1. Aksu found an underwater delta south of the Bosporus; evidence for a strong flow of fresh water out of the Black Sea in the 8th millennium BC
. Nevertheless, Erkan Gökaşan and later Kadir Eris demonstrated that the development of the delta is clearly associated with the Kurbağalı Stream on the east coast, and not with the Black Sea outflow through the strait.
In a series of expeditions, a team of marine archeologists 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 (328.1 ft) of water off the Black Sea coast of modern Turkey. Although radiocarbon dating
of freshwater mollusk remains indicated an age of about 7,500 years, radiocarbon dating in freshwater mollusks in particular can be inaccurate. Such inaccuracies, however, are always in the direction of objects appearing older than they actually are (containing less 14C than expected), so the time given is a maximum age of a freshwater shoreline at that location.
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
circa 5600 BC due to waters from the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
breaching a sill in the Bosporus
Bosporus
The Bosphorus or Bosporus , also known as the Istanbul Strait , is a strait that forms part of the boundary between Europe and Asia. It is one of the Turkish Straits, along with the Dardanelles...
Strait. The hypothesis made headlines when The New York Times
The New York Times
The New York Times is an American daily newspaper founded and continuously published in New York City since 1851. The New York Times has won 106 Pulitzer Prizes, the most of any news organization...
published it in December 1996, shortly before it was published in an academic journal. While it is agreed that the sequence of events described did occur, there is debate over the suddenness, dating and magnitude of the events. Two opposing hypotheses have arisen to explain the rise of the Black Sea: gradual, and oscillating. The oscillating hypothesis specifies that over the last 30,000 years, water has intermittently flowed back and forth between the Black Sea and the Aegean Sea
Aegean Sea
The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...
in relatively small magnitudes, and does not necessarily presuppose that there occurred any sudden "refilling" events.
Flood hypothesis
Bosporus
The Bosphorus or Bosporus , also known as the Istanbul Strait , is a strait that forms part of the boundary between Europe and Asia. It is one of the Turkish Straits, along with the Dardanelles...
, following this scenario. Before that date, glacial
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
meltwater had turned the Black and Caspian
Caspian Sea
The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
Seas into vast freshwater lakes draining into the Aegean Sea
Aegean Sea
The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...
. As glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
s retreated, some of the rivers emptying into the Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
declined in volume and changed course to drain into the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
. The levels of the lakes dropped through evaporation, while changes in worldwide hydrology
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
caused sea level to rise. The rising Mediterranean finally spilled over a rocky sill at the Bosporus. The event flooded 155000 km² (59,845.8 sq mi) of land and significantly expanded the Black Sea shoreline to the north and west. According to the researchers, "40 km³ (9.6 cu mi) of water poured through each day, two hundred times what flows over Niagara Falls
Niagara Falls
The Niagara Falls, located on the Niagara River draining Lake Erie into Lake Ontario, is the collective name for the Horseshoe Falls and the adjacent American Falls along with the comparatively small Bridal Veil Falls, which combined form the highest flow rate of any waterfalls in the world and has...
... The Bosporus flume
Flume
A flume is an open artificial water channel, in the form of a gravity chute, that leads water from a diversion dam or weir completely aside a natural flow. Often, the flume is an elevated box structure that follows the natural contours of the land. These have been extensively used in hydraulic...
roared and surged at full spate for at least three hundred days."
Samplings of sediments in the Black Sea by a series of expeditions carried out between 1998 to 2005 in the frame of a European Project ASSEMBLAGE and coordinated by a French oceanographer, Gilles Lericolais, brought some new inputs to the Ryan and Pitman's hypothesis. These results were also completed by the Noah project led by the Bulgarian Institute of Oceanography (IO-BAS). Furthermore, calculations made by Mark Siddall predicted an underwater canyon that was actually found.
Criticism
While some geologists claim it as fact that the sequence of events described did occur, there is debate over their suddenness and magnitude. In particular, if the water level of the Black Sea had initially been higher, the effect of the spillover would have been much less dramatic. 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 Bosporus, or enough of a difference in water levels (if at all) between the two water basins.Countering the hypothesis of Ryan and Pitman are data collected prior to its publication by Ukrainian
Ukrainians
Ukrainians are an East Slavic ethnic group native to Ukraine, which is the sixth-largest nation in Europe. The Constitution of Ukraine applies the term 'Ukrainians' to all its citizens...
and Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
n scientists including Valentina Yanko-Hombach, who claims that the water flow through the Bosporus repeatedly reversed direction over geological time depending on fluctuation in the levels of the Aegean Sea and the Black Sea. This contradicts the hypothesized catastrophic breakage of a Bosporus sill. Likewise, the water levels calculated by Yanko-Hombach differed widely from those hypothesized by Ryan and Pitman.
In 2007, a research anthology on the topic was published which makes available much of the earlier Russian research in English for the first time, and combines it with more recent scientific findings.
A five-year cross-disciplinary research project under the sponsorship of UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
and the International Union of Geological Sciences
International Union of Geological Sciences
The International Union of Geological Sciences is an international non-governmental organization devoted to international cooperation in the field of geology.-About:...
was conducted 2005–9.
A February 2009 article reported that the flooding might have been "quite mild".
According to a study by Giosan et al., the level in the Black Sea before the marine reconnection was 30 m below present sea level, rather than the 80 m, 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. It also occurred earlier than initially surmised, ca. 7400 BC, rather than the originally proposed 5600 BC. Since the depth of the Bosphorus, in its middle furrow, at present varies from 36 to 124 m, with an average depth of 65 m, a calculated stone age shoreline in the Black Sea lying 30 m lower than in the present day would imply that the contact with the Mediterranean may never have been broken during the Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
, and hence that there could have been no sudden waterfall-style transgression.
Evidence from archaeology
Neolithic
The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...
agriculture had by that time already reached the Pannonian plain, Ryan and Pittman link its spread with people displaced by the postulated flood. More recent examinations by oceanographers such as Teofilo A. "Jun" Abrajano Jr. at Rensselaer Polytechnic Institute
Rensselaer Polytechnic Institute
Stephen Van Rensselaer established the Rensselaer School on November 5, 1824 with a letter to the Rev. Dr. Samuel Blatchford, in which van Rensselaer asked Blatchford to serve as the first president. Within the letter he set down several orders of business. He appointed Amos Eaton as the school's...
and his Canadian colleague Ali Aksu of the Memorial University of Newfoundland
Memorial University of Newfoundland
Memorial University of Newfoundland, is a comprehensive university located primarily in St...
have cast some doubt on this linkage. Abrajano's team, finding sapropel
Sapropel
Sapropel is a term used in marine geology to describe dark-coloured sediments that are rich in organic matter...
mud deposits in the Sea of Marmara
Sea of Marmara
The Sea of Marmara , also known as the Sea of Marmora or the Marmara Sea, and in the context of classical antiquity as the Propontis , is the inland sea that connects the Black Sea to the Aegean Sea, thus separating Turkey's Asian and European parts. The Bosphorus strait connects it to the Black...
which are today associated with freshwater outflow over top of salt-water inflow, have concluded that there has been sustained fresh water outflow from the Black Sea to the Mediterranean for at least 10,000 years. In 2003, Michael Sperling concluded that the Black Sea was not a major freshwater source contributing to formation of the Marmara Sapropel S1. Aksu found an underwater delta south of the Bosporus; evidence for a strong flow of fresh water out of the Black Sea in the 8th millennium BC
8th millennium BC
In the 8th millennium BC, agriculture became widely practised in the Fertile Crescent and Anatolia.Pottery became widespread and animal husbandry spread to Africa and Eurasia. World population was approximately 5 million.-Events:*c. 8000 BC—The last glacial period ends.*c...
. Nevertheless, Erkan Gökaşan and later Kadir Eris demonstrated that the development of the delta is clearly associated with the Kurbağalı Stream on the east coast, and not with the Black Sea outflow through the strait.
In a series of expeditions, a team of marine archeologists led by Robert Ballard
Robert Ballard
Robert Duane Ballard is a former United States Navy officer and a professor of oceanography at the University of Rhode Island who is most noted for his work in underwater archaeology. He is most famous for the discoveries of the wrecks of the RMS Titanic in 1985, the battleship Bismarck in 1989,...
identified what appeared to be ancient shorelines, freshwater snail shells, drowned river valleys, tool-worked timbers, and man-made structures in roughly 100 metres (328.1 ft) of water off the Black Sea coast of modern Turkey. Although radiocarbon dating
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
of freshwater mollusk remains indicated an age of about 7,500 years, radiocarbon dating in freshwater mollusks in particular can be inaccurate. Such inaccuracies, however, are always in the direction of objects appearing older than they actually are (containing less 14C than expected), so the time given is a maximum age of a freshwater shoreline at that location.
See also
- Flood myth
- Noah's ArkNoah's ArkNoah's Ark is a vessel appearing in the Book of Genesis and the Quran . These narratives describe the construction of the ark by Noah at God's command to save himself, his family, and the world's animals from the worldwide deluge of the Great Flood.In the narrative of the ark, God sees the...
- Zanclean floodZanclean floodThe Zanclean flood is a flood theorized to have refilled the Mediterranean Sea 5.33 million years ago, at the beginning of the Zanclean age, between the Miocene and Pliocene, which ended the Messinian salinity crisis...
, Mediterranean Sea 5.33 million years ago
Further reading
- Giosan, Liviu et al. 2009. Was the Black Sea catastrophically flooded in the early Holocene? Quaternary Science Reviews, January 2009, 28(12-2): 1-6. doi:10.1016/j.quascirev.2008.10.012
This article (possibly not identical to the preceding citation) is available online with unrestricted access here at the sponsoring institution's website. - Noah's Not-so-big Flood
- Lericolais, G. http://archimer.ifremer.fr/auteurs/gilles-lericolais.htm et al. 2009. High frequency sea level fluctuations recorded in the Black Sea since the LGM. Global and Planetary Change, March 2009, 66(1-2): 65-75
- "Ballard and the Black Sea"
- Dimitrov, D. 2010. Geology and Non-traditional resources of the Black Sea. LAP Lambert Academic Publishing. ISBN 978-3-8383-8639-3. 244p.
- The late glacial Great Flood in the Ponto-Caspian basin