Unaweep Canyon in the Rocky Mountains is the site of a deep gorge that reveals ancient landscapes and sediments. The inset image is of a "dropstone" from an eons-old glacier. Posted on 07/31/2008 12:07:21 PM PDT by decimon
Look into "deep time" sheds light on period considered analogous to today's climate
Unaweep Canyon in the Rocky Mountains is the site of a deep gorge that reveals ancient landscapes and sediments. The inset image is of a "dropstone" from an eons-old glacier.
Geoscientists have long presumed that, like today, the tropics remained warm throughout Earth's last major glaciation 300 million years ago.
New evidence, however, indicates that cold temperatures in fact episodically gripped these equatorial latitudes at that time.
Geologist Gerilyn Soreghan of Oklahoma University found evidence for this conclusion in the preservation of an ancient glacial landscape in the Rocky Mountains of western Colorado. Three hundred million years ago, the region was part of the tropics. The continents then were assembled into the supercontinent Pangaea.
Soreghan and colleagues published their results in the August 2008, issue of the journal Geology.
Climate model simulations are unable to replicate such cold tropical conditions for this time period, said Soreghan. "We are left with the prospect that what has been termed our 'best-known' analogue to Earth's modern glaciation is in fact poorly known."
"This study is an example of the wealth of untapped climate information stored in Earth's 'deep time' geologic record millions of years ago," said H. Richard Lane, program director in NSF's Division of Earth Sciences, which funded the research. "These kinds of discoveries may greatly improve our understanding and prediction of modern climate change."
As a result of the close proximity of the ancient tropical glaciers to the sea, the toes of the glaciers were likely less than 500 meters above sea level--much lower than the tropical glaciers of Earth's recent glacial times.
"The Late Paleozoic tropical climate was not buffered against cold from the high latitudes, as everyone had thought," said Soreghan. "The evidence we found indicates that glaciers were common at this time, even in tropical latitudes. This calls into question traditional assumptions of long-lasting equatorial warmth in the Late Paleozoic, and raises the possibility of large-scale and unexpected climate change in the tropics during that time."
Popsicle planet ping
Money sentence.
I don’t get the lead - “Look into “deep time” sheds light on period considered analogous to today’s climate”
Analogous to today’s climate?
And I see I italicized that sentence instead of bolding it. Ah, well.
 |
||
| · join · view topics · view or post blog · bookmark · post new topic · | ||
Money sentence.
The real money quote, sitting on the editor's floor, was the rest of the sentence:
"...but we are 100% certain that these same models are 100% accurate when we use them to predict global warming."
I’ve been to this canyon. A deep gash cut right through the middle of the Uncompaghre Plateau in western Colorado. And the mystery is, how did it form? There are only a couple of minor creeks that drain it.
How arrogant “we” are to assume today’s climate is the norm for Erf.
Woof. :-)
Look at the situation this way - with so much of the planet covered with an albedo of snow and ice, there was precious little open land available for the growth of plant material, and most of that of the variety of what would grow in a sub-Arctic fen. Tamarack, ferns, swamp alders, and bulrushes.
Therefore, with carbon dioxide not being used so much by growing plant life, and the average ocean temperture being lower, perhaps by some several degrees worldwide, a greater proportion of the carbon dioxide would be absorbed by the cooler water. This, in turn, would make the oceanic plant life much richer and more varied, enriching the oxygenation of the water, allowing species with a higher biological oxygen demand to grow and multiply, creating the ancestors to present-day salmon, trout and cod, cold-water species which go teeming in the sea.
This is one of the reasons why the biological food chain is so much more fecund in northern latitudes than in tropical regions. Undersea life in warm tropical waters is much more varied, but it is actually a much more spare existence than that of cold-water regions. The warm waters have less dissolved oxygen and carbon dioxide than waters at frigid or near freezing conditions.
Sounds as good a construct as any.
Nor can climate models accurately replicate the last 20 years of actual climate experience for which we have good data, but apparently not sufficient data.
Climate models do a wonderful job of addressing hopes, dreams, fears, and secular religious beliefs. Predicting actual phyiscal phenomena is not quite there yet.
In 1980, we were stripping 110 feet with a dragline, uncovering nice 7-8 feet of coal when we encountered a pocket of sand and gravel, missed by the exploration drill. The sand looked like a stack of gray/white shale, but went down past the fire clay that the coal was laying on. Since we couldn’t hold the highwall for the next cut, it was necessary to dig a box cut and leave a ledge of undistrurbed shale to continue mining the reserve. Our geologist believed this was a river channel void dating back to about the time the coal was formed, or about 250 million years.
YEC INTREP
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
