Current status of the Early Holocene Flood hypothesis in the Black Sea

Category Tectonic & Seismotectonic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Yanko-Hombach, Valentina۱; Gilbert, Allan۲; Dolukhanov, Pavel۳
Holding Date 11 October 2008

The Black Sea’s environmental significance is reflected in the 2005—2009 IGCP 521 and INQUA 501 projects focused on the "Black Sea–Mediterranean Corridor during the last 30 ky with respect to sea-level change and human adaptation". These projects are testing the Early Holocene flood hypothesis (Ryan et al. [1997] at 7.2 ky BP or [2003] at 8.4 ky BP), in which a catastrophic Mediterranean inflow caused rapid sea-level rise in the Black Sea from ca. —100m to its present mark. The inundation abruptly impacted prehistoric human societies in the surrounding areas and formed the basis for the biblical Great Flood legend.
The hypothesis was closely examined in recent publications: a special June 2007 issue of Quaternary International (Yanko-Hombach and Yilmaz, 2007) and a major book, The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement (Yanko-Hombach et al., 2007). Most researchers found Early Holocene flooding of the Black Sea to be a myth, reporting the following. The Black Sea was a semi-fresh to brackish (but never freshwater) Neoeuxinian lake with a level about —100m below present at the LGM. About 17 ky BP, factors related to deglaciation raised the lake level to —20m, spilling excess semi-fresh water into the Sea of Marmara and forming a mid-shelf delta at the southern end of the Bosphorus Strait (Hiscott et al., 2007). After ca. 9.8 ky BP, the level of the Black Sea never again dropped below the —50m isobath, nor did it exhibit fluctuations greater than about 20m. The brackish Pontic lake ultimately became a semi-marine basin through oscillating Marmara seawater entry, with periodic immigration of Mediterranean organisms with the first wave of immigration at ca. 9.5 ky BP.
Contra Turney and Brown (2007), no significant cultural changes characterize the archaeological record of the region during the 8.4–7.2 ky BP interval coeval with the proposed flood. At this period, the North Pontic steppe and the Caucasian coast supported Mesolithic forager groups who possessed neither domestic plants nor animals but relied increasingly on aquatic resources, harvesting of wild plant foods, and a lifestyle combining sedentism with seasonal transhumance. Sites cluster in landscapes with diverse and predictable wild resources, especially marine estuaries, lakes, and river floodplains.
Even if the Black Sea rose catastrophically and flooded the North Pontic plain, few foraging bands would have been displaced from the now drowned shelf area considering the low population density typical of steppe-dwellers. Mesolithic and early Neolithic archaeological data in Ukraine provide no support for a sudden cultural shift at the time of the proposed flood (Anthony, 2007). The earliest indications of agriculture come from the Zagros foothills in the Near East: 11.7—8.4 ka BP (Bar-Yosef, Meadow, 1995) corresponding to the cool, dry Younger Dryas climatic period, including the subsequent rapid increase in rainfall at the beginning of the Holocene.