> Estimates of "absolute" sea level are important (though it's partly
a matter of whose figures you believe -- the main point on which most
specialists agree is that there was a catastrophic rise ca. 7600 BC),
but there are other factors that have to be considered. The sheer
mass of the increased Black Sea and the Caspian would have caused
their beds to depress, but the surrounding areas would have
experienced compensatory uplift. This means that the present
elevation of potential spillways (very close to sea level) is now
probably higher than at the time of the Euxine Event (in addition to
the Don-Volga route there's another viable "floodway" along the
Rostov-Makhachkala line, just N of the Caucasus. The dynamics of such
processes is very complex, and our "armchair palaeohydrology" is of
course speculative in the extreme. However, the region in question is
attracting more and more scholarly attention and there should be no
shortage of expert opinions in the near future. I think, by the way,
that it was the replenished Black Sea that overflowed into the
Caspian, not the other way over.
Piotr the to and fro movements of water through the Caspian-Euxine
and Aral Seas is indeed very complex.
Firstly, after the Glacial Maximum of 18,000 BCE there was a huge
accumulaton of meltwater Siberia in the Mansiyskoe (West Siberian)
lake. Dammed from flooding into the Arcic it instead spilled over
through the Tumen channel into the Aral Sea and thence into the
Caspian which flooded over into the Euxine (which was then a
freshwater lake). Have a look at
The level of the Black Sea was significantly higher than it is at the
moment. At that time the Black Sea drained into the Mediterranean
via a different route than the Bosphorus, flowing between Karasu and
Denizkoy on the Turkish coast, southward to the town of Adapazari and
then westward to the town of Ozmit on the Sea of Mamora and hence
into the Mediterranean.
The weight of this meltwater caused a depression of the sediments,
exactly as you describe.
Firstly the Mansiykoe Lake drained northward via the channels of the
Ob and Yenisei Rivers, and the Aral and Caspian Seas became separate
again. (the release of this water may have caused the Younger Dryas
cold snap circa 12,900-11,500 BP (10,900-9,500 BCE), during which
periglacial conditions returned to much of this area. During the
warm Atlantic phase which followed the Boreal conditons of the
Younger Dryas, evapouration from this area exceeded precipitation and
the rivers ran in the oposite direcion.
A further sudden cold-snap (8,200 BP, 6,200 BCE) saw a return to cold
conditions and an arid period which was felt around the world. (It
caused the collapse of Per-Pottery Neolithic and pumped the Semitic
peoples out of Africa and into Palestine for instance). At this time
the channel between the Caspian and the Black and Aral Seas were
divided, and all three by 5,500 BCE had falled significantly to
levels far lower than today (ancient shorelines are being found in
both the Caspian and the Aral Sea.
The eustatic change caused by the release of the meltwaters was not
as great as that caused by the loss of the Icesheats to the north.
Sea levels rose throughout the Arctic regions, the Balic catchment
area, Scandinavia and Scotland, with sea level falls in the English
Channel, the Netherlands, the North German Plain and the catchment
area of the north of the Black Sea.
The Laurentide Glacier stretching from Nunavit across the Foxe Basin
to Quebec had dammed a huge meltwater lake behind as an expanded
Hudson's Lake, which had risen to drain into the Missippi and
Missouri system in the east and out through the Saint Lawrence in the
East. The collapse of this Glacier, at about 6,200 BCE is what had
caused the cold snap of the sub-Boreal period.
Research is showing that these sudden changes in climate, often
occurring on an interval of about 1,500 years, seems due to
the "switching off" of the Oceanic Global Conveyor Belt in the North
Atlantic. What normally happens is that warm salty water from the
Gulf meets the cold waters of the Arctic and loses its temperature,
sinking to form a deep ocean current that flows south around Africa
and Australia to rise in the North Pacific off British Columbia. As
a surface current it then flows back, through Indonesia, around South
Africa as the Benguela Current into the Carribbean and then as the
Gulf Stream north again. It contributes 30% of the temperatures of
Western Europe (which would otherwise by Siberian).
Excessive amounts of fresh water released in the North Atlantic by
glacial melt interferes with the sinking mechanism and the Global
conveyor may be turned off for up to 2-300 years. The Gulf Stream in
extreme cases may not continue further north than Portugal, with the
result that the North Atlantic is covered with Icebergs.
The stopping of the Global Conveyor seems to have occurred in a
period of less than 5 years after the flush of meltwater first from
Lake Mansiykoe and secondly nearly 2,200 years later by the Hudson
The arid coditions caused an evapouration of continental lakes, with
the decline in continental water bodies, and the return of warmer
weather, sea levels rose. The Black Sea flood was one result.
By 5,500 BCE the arid conditions that had hit the Black Sea region
was ending and wetter conditions were returning to the Sahara. (Lake
Chad peaked 4,000 BCE to its highest levels ever). The Tarim Basin
north of Tibet and Lake Eyre in Australia also showed high levels.
This caused sea levels world wide to fall. This wetter phase is what
drew the Andronova Indo-Europeans into the Yenesie Basin and sent
them south to the shores of the Tarim Lake. The Black Sea would have
been isolated again after this period except that the Black Sea
Cascade, many thousands of times bigger than Niagra had cut a channel
through the Bosphorus, that was still flowing. This Channel still
has a reverse countercurrent flowing at depth (the Argonauts knew
this. They had a sea anchor that dragged them into the Black Sea
against prevailing winds.
For the sudden climatic transitions of the Holocene (last 10,000
years) have a look at
The Ignatius Donnelly site on the web (already mentioned) gives
reference to another climatic anomaly of 3,150 BCE, and there was
another at the end of the late Bronze Age at 1,200 BCE, which saw
extremely cold arid phases. It would appear 3,150 was due to a huge
volcanic explosion somewhere (the hunt is on to find it), similar to
the way that the Little Ice Age was due to the explosion of Lake
Taupo in New Zealand.
It seems that there was a corridor between ice covered mountains and
glacial lakes that was only penetrated at two or three points across
the whole of Siberia during the late ice age and well into the
Holocene period. The rapid melting of the Ice from 10,000 BCE and
the isostaic movements of the earth's crust seems to have set off a
number of major earthqakes across fault-lines in the region that
could have caused major changes in meltwater distribution, especially
in low lying areas where changes in just a few feet could cause major
changes in the flow of river catchments (north to the south or back
Regarding the movements of cultures, it seems that there was a
connection early in the Late Pliestocene period (from 40,000 until
20,000 BCE) across the full range of the steppes. Thus Upper
Paleolithic cultures like the Aurignacian and Gravetian seemed to
range across the full range of the mammoth area. From 18,000 BCE
until about 7,500 BCE this pattern of movement seems to have been
cut, and cultural movements were impossible between the Eastern
steppes of Mongolia and the Western Pontic steppes.
This had two effects. Firstly it isolated Upper Paleolithic cultures
genetically. The classic mongoloid features, which show adaption to
a cold environment (eg. Large body core (head and body) versus
reduction in length of limbs (as a resistance to temperature loss and
protection against frostbite), increase retention of keratin in the
skin (giving the skin a slightly yellowish colour), and the
epicanthic fold of the eye (as a resistence against snow blindness)
all seem to have evolved during this period. This east and west
Siberian isolation during this time frame, seems to have been
confirmed by Cavalli Sforza's genetic work.
Secondly, it mean that cultural innovations did not travel either
east or west across the steppe, but, with the warming of the climates
came from the South. Thus the Murzak Koba culture and the later
Grebeniki culture did not come from the East across from Central Asia
(as Glen would assert, with his Steppe languages), but came rather
from the South, the Balkan "Danubian Gorge" mesolithic culture.
Similarly the Afonsova culture and the Keltiminar culture also seem
to have developed out of southern mesolithic cultures moving north.
It was only late in the development (after the Melt-water lakes had
completely disappeared) that we find clear evidence of people coming
from the Western Steppe influencing the cultura developments in these
areas. These Western steppe people seem to have come from the Uralic
area (introducing the ski as a new transport technology). The new
amalgam cultures moved north with the warming of the climate, until
they reached the Arctic coast. There they developed a culture based
upon skin covered boats (kayaks) hunting seals and small whales.
This culture spread rapidly along the Arctic shoreline carrying
Yukaghir language peoples in an easterly drecion.
Thus Uralic (and the language features connecting Uralic to Altaic
languages) came not from Eastern Siberia or Central Asia (as Glen
would assert), but rather they came in a west-east movement of
mesolithic cultures travelling eastward over the top of a substrate
of mesolithic cultures which received their culture from the south.
This hypothesis as been confirmed on two fronts.
1. Firstly on the basis of the spread of the technology of the bow
and arrow. Western Steppe peoples (living on the Pontic steppe,
North of the Black Sea) seem to have derived their bow technology
from the Balkans. A superior bow technology (using reflex bows and
laminates of horn and wood), developed in Central Asia out of bows
found which arrived in the area from Iran. This second bow was
introduced to the West only with the Scythians. If Glen's
was correct and Indo-European languages arrived in the area north of
the Black Sea from Central Asia, it is hard to see how they would
have abandoned the superior bows of Central Asia for an inferior bow
of Western Europe.
2. Secondly on the basis of the genetics of the dog. North East
Asian dog breeds are all derived from the dogs of Northern Iran.
European and Pontic dogs are all derived from the breeds of Anatolia
and the Balkans. One would expect that a mesolithic "Steppe"
Indo-European language group travelling into the Pontic Steppe as a
mesolithic culture would have brought their dogs with them. This is
exactly what happened the mesolithic cultures of Central Asia
brought their bows and their dogs with them from Iran. The Proto-
Indo-European cultures of the Pontic Steppe brought their mesolithic
bows and dogs with them from the Balkans.
Hope this helps.