CanWest News Service
Monday, November 19, 2007
A British scientist has found evidence linking the catastrophic
collapse of a glacial ice dam in Canada more than 8,000 years ago and
the rapid spread of agriculture across Europe around the same time.
The dramatic discharge of freshwater from prehistoric Lake Agassiz -
which covered much of Central Canada at the end of the last ice age -
has long been blamed for altering global climate patterns and raising
sea levels around the world by at least a metre in a matter of months.
The deluged shorelines caused by the colossal Canadian gusher have
even been associated with the "great flood" myths common to many
ancient cultures - including the biblical story of Noah's Ark.
Now, University of Exeter geologist Chris Turney believes he has
traced the sudden proliferation of farming across neolithic Europe to
an exodus of coastal people moving inland to escape the results of the
Agassiz flood.
"It still blows my mind to think that a release of water from Canada
could set off a cascade of changes all the way across in Europe,"
Turney told CanWest News Service. "It just goes to show how people and
the environment are intimately linked."
The existence of a supersized Lake Agassiz, named for a leading 19th-
century geologist, has been known since the late 1800s. Formed some
12,000 years ago from the meltwater of retreating glaciers at the end
of the last full ice age, the lake was encircled by beaches still
visible today as sandy ridges throughout Central and Western Canada.
Initially centred around the present Ontario-Manitoba border, Lake
Agassiz formed, at its greatest extent, a 1.5-million-square-kilometre
freshwater basin - an area larger than the combined areas of
Saskatchewan and Manitoba.
University of Manitoba geologist Jim Teller's reconstruction of the
lake's dying throes has kick-started a worldwide wave of research into
what was undoubtedly one of the most awesome natural events in
Canadian prehistory.
With the lake at the greatest width and depth ever in its 4,000-year
lifespan, the glacier that had dammed Agassiz's northern shore broke
somewhere along ice-bound Hudson Bay. A huge torrent gushed into the
ocean, draining a volume of fresh water equal to about 15 Lake
Superiors in a few months.
Some of this country's earliest aboriginal occupants may have even
witnessed the epic occurrence since the peopling of Canada roughly
coincides with the retreat of the glaciers.
Teller has also theorized Agassiz's final, cataclysmic burst caused
such a surge of seawater around the world it might have given rise to
the Noah's Ark saga and other ancient accounts of massive floods.
Among the effects, scientists believe, was the breaching of an earthen
barrier between the Mediterranean and Black seas in southeast Europe
and extensive flooding of the Black Sea shoreline.
Turney, author of the newly published Bones, Rocks and Stars: The
Science of When Things Happened, specializes in reconstructing ancient
events from the archeological and geological record.
His study, published in the latest edition of Quaternary Science
Reviews, shows that up to 145,000 people from farming sites near the
Black Sea would have been forced out of their lands by the flooding
and into territory occupied by hunter-gatherer cultures of inland
Europe.
"The collapse of the Laurentide Ice Sheet and release of freshwater
8,740 to 8,160 years ago abruptly raised global sea levels by up to
1.4 metres," the study says. "Flooding of coastal areas led to the
sudden loss of land favoured by early farmers and initiated an abrupt
expansion of activity across Europe, driven by migrating Neolithic
peoples."
Turney tracked the sudden spread of European farming about 8,000 years
ago by mapping the locations and dates of the earliest known
agricultural settlements discovered by archeologists.
What the data shows, he says, is a clear sequence of flooding,
migration and resettlement of farmers across Europe after the Lake
Agassiz deluge.
Canadian Article
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