Posted on 11/01/2007 10:28:47 AM PDT by blam
Melting Glacier Reveals Ancient Tree Stumps
LiveScience.com
Tue Oct 30, 2:15 PM ET
Melting glaciers in Western Canada are revealing tree stumps up to 7,000 years old where the region's rivers of ice have retreated to a historic minimum, a geologist said today.
Johannes Koch of The College of Wooster in Ohio found the fresh-looking, intact tree stumps beside retreating glaciers in Garibaldi Provincial Park, about 40 miles (60 kilometers) north of Vancouver, British Columbia.
Radiocarbon dating of the wood from the stumps revealed the wood was far from fresh—some of it dated back to within a few thousand years of the end of the last ice age.
"The stumps were in very good condition sometimes with bark preserved," said Koch, who conducted the work as part of his doctoral thesis at Simon Fraser University in Burnaby, British Columbia. Koch will present his results on Oct. 31 at the Geological Society of America annual meeting in Denver.
The pristine condition of the wood, he said, can best be explained by the stumps having spent all of the last seven millennia under tens to hundreds of meters of ice. All stumps were still rooted to their original soil and location.
"Thus they really indicate when the glaciers overrode them, and their kill date gives the age of the glacier advance," Koch said. The age of the newly revealed ancient trees also indicates how long the glaciers have covered this region.
The recently warming climate released the stumps from their icy tombs, Koch said.
Koch compared the kill dates of the trees in the southern and northern Coast Mountains of British Columbia and those in the mid- and southern Rocky Mountains in Canada to similar records from the Yukon Territory, the European Alps, New Zealand and South America. He also looked at the age of Oetzi, the prehistoric mummified alpine "Iceman" found at Niederjoch Glacier, and similarly well-preserved wood from glaciers and snowfields in Scandinavia.
The radiocarbon dates seem to be the same around the world, according to Koch. There have been many advances and retreats of these glaciers over the past 7,000 years, but no retreats that have pushed them back so far upstream as to expose these trees.
The age of the tree stumps gives new emphasis to the well-documented before-and-after photographs of retreating glaciers during the past 100 years.
"It seems like an unprecedented change in a short amount of time," Koch said. "From this work and many other studies looking at forcings of the climate system, one has to turn away from natural ones alone to explain this dramatic change of the past 150 years."
Well, sure it's probably an historic minimum. History just doesn't go back far enough to be meaningful.
That jumped out at me too...though they might not have been ground up beyond a certain point.
Greenland has at least one farm that was in operation for 200 years which recently became unfrozen enough to be found...and it had been frozen hard enough since the MWP that the excavators could identify the animal smells. The farm was discovered based upon the finding of a tree-stump.
Obviously, George W. Bush has tried this before and failed. He'll probably succeed this time unless he and Cheney are impeached and hanged.
Where’s Mulder and Sculley?
How is it that the tree stumps remain intact in their original locations. Didn't we all learn in school that the power of the glaciers moving across the land scooped out the Great lakes and created the Kettle Moraine in Wisconsin, dropping tons of rocks in this region, which was the southern edge of the glacier?
OMG — I wonder of the poor Greenland farmers received government assistance when their farm froze — disaster relief... s/off
Does this dork have any clue how stupid this statement really is? A relatively rapid and long lasting change happened 7,000 years ago, when the area went from warm and alive to a frozen glacier. A warming now is not unprecedented, either as being warm or as a change.
My guess is a heavy rain fell and flooded the area which then froze solid. A glacier then advanced over the top of the ice field and slid above the surface, taking the tops of the trees, but leaving the stumps intact below. As the glacier now retreats, the underlying ice field also melts, revealing remnants of the region’s pre-glacial environment.
The Coming and Going of Glaciers: A New Alpine Melt Theory
http://www.freerepublic.com/focus/f-news/1425559/posts
Shsssssssssh.
You’re not supposed to have noticed that “inconvenient trend” ....
And I know, because Gaea told me......
"So many stumps, so little dynamite. Guess I'll just have to use spin, and hope nobody notices the inconvenient possibilites...," he added.
The remains of Al Gore's ancestors?
Authors: G.T. Creber, J.E. Francis Keywords: Antarctica, arctic, Glossopteris, greenhouse climate, high latitude, palaeobotany, photosynthesis, photoperiodism, polar light regime, secondary wood Abstract:
For many millions of years in the geological past, Earth was in a ‘greenhouse’ condition when the tropical zone was more extensive than now, extending from about 40° N to 40° S. Within this zone the fossil wood shows no growth rings or only weakly developed ones, as in the tropics today. The temperate zones occupied the remainder of the planet reaching the poles to the exclusion of the present day boreal zones. Consequently, abundant tree growth was possible at the highest latitudes where the annual solar energy input regime is very different from those at lower latitudes. Towards the poles the growing season has 4380h of solar energy input, much of it being received in 24h periods of continuous daylight. That this makes for excellent tree growth is evidenced by the wide growth rings, containing as many as 200 cells between one ring boundary and the next, as recorded in the fossil wood. It is clear that if efforts to prevent global warming are not successful, then the polar regions will become very important for forestry as the ice caps recede. Furthermore there will be a positive feedback effect; as the albedo of tree crowns is so much greater than that of ice, much more solar energy will be retained in the atmosphere.
(Believe it or not!)
Not. :’)
Nothing like the speed of the change that buried these trees intact and kept them buried so they couldn't rot I'm guessing. Must have been one heck of a snowstorm 7,000 years ago.
That’s gotta leave a mark.
You may be onto something. Remember back in 2000 when it came up during the second Bush/Gore presidential debate that Bush owned a lumber company, and he joked with the audience asking "Wanna buy some wood"?
Well, now we know... /grin
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