Posted on 03/15/2002 8:06:39 AM PST by cogitator
Antarctic Ice Core over 500,000 Years Old Extracted
CAMBRIDGE, UK, March 14, 2002 (ENS) - Ice more than half a million years old has been taken from deep below the East Antarctic ice sheet, setting what is believed to be a new record.
The multi-nation European Project for Ice Coring in Antarctica (EPICA) drilling at Dome Concordia has recovered ice believed to be around 530,000 years old, according to the British Antarctic Survey.
Previously the Russian Vostok ice core, dating back 420,000 years, was regarded as the oldest ice to be drilled from Antarctica.
The EPICA team, from 10 countries, recovered their ice from a drill hole that reached 2,864 metres (9,396 feet) in depth - compared to the Vostok hole's 3,538 metres (11,607 feet).
According to British Antarctic Survey scientist Rob Mulvaney, the answer to this paradox lies in differences in the rates of thinning of the ice sheet at the two sites, which is linked to what lies beneath them.
At Dome Concordia, high on East Antarctica's plateau, the ice lies on rock, whereas at Vostok, it stands over the huge Lake Vostok.
"If the bottom of the ice sheet lies on rock, and there is no melting, then the ice at the very bottom is almost infinitely old, and the annual layers infinitely thin," Mulvaney said.
"Because Vostok ice is melting at the base, the oldest layers have been lost, and the vertical column of ice does not need to thin so rapidly to maintain the surface equilibrium."
The EPICA project exceeded its targets in the past season, drilling more than 350 metres (1148 feet) beyond its goal, and leaving just 380 metres (1246 feet) to be drilled next season.
The British Antarctic Survey (BAS) said field analysis already suggests that the ice retrieved coveres four glacial and interglacial periods, with every prospect of several more climate cycles before the team reached either disturbed ice or bedrock.
EPICA's chief scientist, BAS's Eric Wolff, said the drilling program took scientists back to the future. "Information about how climate worked in the past is locked in the ice," he said. "Understanding this helps predict future changes."
The EPICA project has also begun drilling 3,000 kilometers (1,864 miles) from Dome Concordia in Dronning Maud Land in search of more detailed information at a site that receives double the snowfall of Dome Concordia.
Even so, it is cores at Dome Concordia that will provide the longest possible record of the past atmosphere, BAS said.
The single most important source of information about past climate change and the associated composition of the atmosphere are the two large ice caps of Greenland and Antarctica, EPICA says in its mission statement.
"Analysis of ice cores is therefore the most powerful means we have to determine how climate has changed over the last few climate cycles, and to relate this to changes in atmospheric composition, in particular to concentrations of the principal greenhouse gases - CO2, CH4 and N2O - carbon dioxide, methane, and nitrous oxide."
EPICA says the program "has been motivated primarily by the urgent need to predict more accurately how global climate is likely to respond to increased emissions of greenhouse gases as a result of human activities."
Yup. They will be careful though because some years could be compressed due to the weight or even melted together due to a slightly warmer period. The ice cores are not as dependable (like tree rings) as a year to year record but, are best at monitoring 'periods'. Some years will be clearly discernable and identifiable as a particular year but, not all years. There will be years missing but the date of those missing years will be known.
Where's the Hundred-Billion-Year-Old-Ice?!</font size>
Either the "old earth" heated up dramatically long ago, or it's not quite so old.
It used to be hot
Then not
Global Warming s'not
AMPU
What about the first point of my reply regarding interpretation of data, do you also have a comment on that?
As my grandfather used to say, "If the recipe called for water, they'd have put it in the bottle."
To believe that they would not tend to skew the facts in their favor in order to continue to receive international funding is one of the lies foisted on us by environmentalists.
Actually, I beleive the Greenland iceplate is much more dynamic in its movement then the antarctic one. It could be that the samples from this ice field are not as effected by "smear".
What sort of a climate change caused all of this ice to be formed in the polar regions? How does this relate to the current global warming hoax being foisted on us by the environmentalists?
Of course it does, but it's alot better than the liberal method of drawning conclusions and making "predictions" with no data at all.
As far as cost goes, not much compared to all to the cost of the "environmental impact" statements and such required before anybody can do much of anything, which in turn pales in comparison to the cost of welfare, or even welfare fraud.
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It's ammusing that they tack on the extra significant figure when they are pretty much taking a wild guess.
No, they're not "pretty much taking a wild guess". It's not all that hard to date things accurately to within two significant digits (which is all they're claiming in the above figures), especially when the item under consideration is of a nature to allow multiple dating methods to be used as "cross-checks" of each other, as is the case for arctic ice cores.
They're not guessing, they're measuring.
Wow, cool -- so the ice in your freezer contains captured pockets of atmospheric air from hundreds of thousands of years ago, ancient pollen grains from extinct plants, layers of dust from pre-historic volcanic eruptions, and micrometeorites from across several millennia?
I'm impressed.
I don't know. It's a legitimate point to ask and I don't fault you for it. I just didn't want anyone else to think that this was a U.S. study. Many nations include research as part of their national science efforts, so this comes out of the British science budget.
What sort of a climate change caused all of this ice to be formed in the polar regions? How does this relate to the current global warming hoax being foisted on us by the environmentalists?
Good question. Looking WAY back, one of the causes that has been examined for the basic cooling of the Earth since the Eocene (the second period of the Cenozoic) was the formation of the Himalayas.
From Global Climate Change Student Guide: Internal Forcing Mechanisms: Orogeny
"Ruddiman & Kutzbach (1991) have proposed that the uplift of the Tibetan Plateau, the Himalayas and the Sierra Nevada in the American south-west may have induced a global cooling during the last 40 million years (see section 5.2.2.3). Raymo & Ruddiman (1992) also suggest that increased uplift of these regions exposed more rock, thereby increasing the rate of physical and chemical weathering. During chemical weathering, carbon dioxide is extracted from the atmosphere to react with the decomposing rock minerals to form bicarbonates. These bicarbonates are soluble and can be transported via rivers and other fluvial channels, finally to be deposited on ocean floors as sediment. In essence, carbon dioxide is sequestered from the atmosphere, thereby decreasing the Earth's natural greenhouse effect, causing further cooling."
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