Geoscience and Environment

Project

Scope of the Project

This project is limited in scope. The question asked is this: given the locations of the land drowned by the flooding of the Black Sea, the areas of land, and the slope of the land, how plausible is the claim by Ryan and Pitman and others that migration out of the Black Sea Basin "accelerated the dispersal of early neolithic foragers and farmers into the interior of Europe"? How plausibe is the claim by Ryan and Pitman that the Black Sea flood had a similar impact on dispersing early neolithic foragers and farmers south into the Levant, Egypt, the Tigris and Euphrates valley, and east into the interior of Asia?

Approach

The human impact of the flood depends to some extent on the area of land affected, the population density, and the means of livelihood. The first step is to estimate the amount of land lost and the mumber of people living on the land. To do this a digital elevation model ( ETOPO2) of the Black Sea was processed to estimate the area of land that was drowned using the IDRISI software package. Cross-sectional profiles were drawn across the shoreline at six places to determine the slope of the land and the extent of land drowned.

Population densities for early neolithic farmers have been estimated by archaeologists for the fifth millenium B.C. at about 35 persons/km2 in locations suitable for farming (Gregg, 1998). These densities may be higher than those possible a thousand years earlier. Moreover, the estimate is for settled areas which may have represented a small part of the total land area. Most land was probably still inhabited by mesolithic foragers. Nevertheless, Linearbandkeramik (LBK) people in parts of Germany reached densities of about 0.01 person per km2 (Fagan, 1998). The figure cited by Fagan probably includes a considerable area of forested land.

For the purpose of this study, two population density estimates will be used: 0.1 person per km2 and 10 persons per km2. These estimates differ by a factor of 100, the higher figure for neolithic farmers, the lower figure for mesolithic foragers.

Land Areas Drowned

The map on the right shows the area of modern land the former sea and the area drowned, assuming the depth to the ancient shelf was 105 meters.


Areas (GIF 4K)


The map below shows only the land drowned by the flood. In general, level land is more suited to farming than sloping land. The black lines represent profiles drawn across the shoreline. Clicking within the rectangles displays cross-sections of the coast. Cross-sections AA1 to CC1 show relatively level land compared with profiles DD1 to FF1. The areas shown in pink and brown might therefore be more suited to farming than other areas, depending on soil and rainfall.

The area of the sea before the flood was about 340,000 km2 and the area flooded about 124,000 km2. The area of sea increased by about 36%. About 90% of the land lost was along the coasts of Thrace, Bulgaria, Romania and the Ukraine, shown in pink (67,900 km2) and brown (44,400 km2). The lower and higher population estimates for the pink area would be 6,700 and 679,000, and for the brown area, 4,400 and 444,000. Foraging populations of 6,700 and 4,000 shifting inland might meet resistance from foragers inland with established territories, but no long-term impact would be expected.

Farming may have started in the southern part of the pink area (Thrace, Bulgaria, Romania) around 8,000 years ago (Lazarova, 1995). If 5% of the pink area was settled by farmers, the number having to shift inland would be about 35,000, a massive population shift with potential long-term cultural impact.

Archaeologists have discovered many early neolithic sites in the valleys leading into the Ukraine north from the northern part of the pink area and the brown area (Mallory, 1996). Most of the evidence points to development of farming by indigenous peoples. If 0.25% of the pink and brown areas was settled by farmers, the number having to shift inland would be about 25,000, almost as big a population shift as in the southern area, with similar potential long-term cultural impact.

No other contiguous area of land accounts for more than 1% of the total land lost. Along the northeast coast six small areas account for about 3,500 km2, 2.8% of the total lost. Along the southeast coast five small areas account for about 1,800 km2, 1.5% of the total. The central part of the south coast has three small areas with 1,600 km2, 1.3% of the total. The southwestern part of the coast, not including the area in pink, has four small areas with 2,300 km2, 1.8% of the total. There are smaller patches of land accounting for 2.6% of the total, none of which seem large enough to support viable cultures with the capacity for long-term cultural impact. Moreover, hillsides slope more steeply in these areas suggesting that farming would be more difficult than along the west and northwest coasts.

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