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Geomagnetic field reverses in a flash
2 Sep 10 - Rocks just north of a truck stop along I-80 in Battle Mountain, Nevada, provide new evidence of super-fast reversals of Earth’s magnetic polarity.
Geomagnetic reversals - times when a compass would have pointed toward Antarctica instead of toward the Arctic - have occurred more often than is generally known.
Polarity reversals occur every couple hundred thousand years, and (supposedly) take about 4,000 years to make the change, says this article in Science News.
The Nevada rocks suggest that this particular reversal happened at the amazing rate of one degree per week — a flash in geologic time.
A paper describing the discovery is slated to appear in Geophysical Research Letters. Flipping in record time (Image:
G.Glatzmaier/Los Alamos National
Laboratory/P.Roberts/UCLA/SPL)
Scott Bogue, a geologist at Occidental College in Los Angeles and his colleague, Jonathan Glen of the U.S. Geological Survey in Menlo Park, California, went to Nevada to study a series of well-preserved lava flows. As each flow had cooled into solid rock, it preserved the orientation of the magnetic field at the time.
The two geologists found that the rocks in one particular lava flow had reoriented themselves a whopping 53 degrees in one year, suggesting that the magnetic field had changed direction at approximately one degree per week.
This is only the second report of such a speedy reversal. The first report, published in 1985, was based on a study of rocks formed from ancient lava flows at Steens Mountain, Oregon. That report, which indicated a change of three to six degrees per day, has never gained widespread acceptance.
[Although this article says the first report was published in 1995, I mention a report published in 1985 by Prévot, Mankinen, Coe and Grommé in both "Not by Fire but by Ice" ( p.191) and "Magnetic Reversals and Evolutionary Leaps" ( p. 95).]
Regardless of when that first report was published, this new discovery bolsters the theory that reversals can happen very quickly, over a matter of years instead of millennia.
I've received a lot of flack over my assertions that magnetic reversals can occur in as little as 30 days. I cited the rapid reversals in the lava flows on Steens Mountain as part of my proof, so I'm glad to see this new discovery in Nevada.
“We’re trying to make the case that [the new work] is another record of a superfast magnetic change,” says Bogue, lead author of the paper.
As might be expected, not all experts are convinced.
"The last stable reversal occurred 780,000 years ago," the article continues. "Some geologists argue the Earth is overdue for a reversal and might even be entering one now, as the geomagnetic field has been getting weaker over the past 150 years or more."
http://www.evolutionaryleaps.com/Geomagnetic_field_reverses_in_a_flash.htm
2 Sep 10 - Rocks just north of a truck stop along I-80 in Battle Mountain, Nevada, provide new evidence of super-fast reversals of Earth’s magnetic polarity.
Geomagnetic reversals - times when a compass would have pointed toward Antarctica instead of toward the Arctic - have occurred more often than is generally known.
Polarity reversals occur every couple hundred thousand years, and (supposedly) take about 4,000 years to make the change, says this article in Science News.
The Nevada rocks suggest that this particular reversal happened at the amazing rate of one degree per week — a flash in geologic time.
A paper describing the discovery is slated to appear in Geophysical Research Letters. Flipping in record time (Image:
G.Glatzmaier/Los Alamos National
Laboratory/P.Roberts/UCLA/SPL)
Scott Bogue, a geologist at Occidental College in Los Angeles and his colleague, Jonathan Glen of the U.S. Geological Survey in Menlo Park, California, went to Nevada to study a series of well-preserved lava flows. As each flow had cooled into solid rock, it preserved the orientation of the magnetic field at the time.
The two geologists found that the rocks in one particular lava flow had reoriented themselves a whopping 53 degrees in one year, suggesting that the magnetic field had changed direction at approximately one degree per week.
This is only the second report of such a speedy reversal. The first report, published in 1985, was based on a study of rocks formed from ancient lava flows at Steens Mountain, Oregon. That report, which indicated a change of three to six degrees per day, has never gained widespread acceptance.
[Although this article says the first report was published in 1995, I mention a report published in 1985 by Prévot, Mankinen, Coe and Grommé in both "Not by Fire but by Ice" ( p.191) and "Magnetic Reversals and Evolutionary Leaps" ( p. 95).]
Regardless of when that first report was published, this new discovery bolsters the theory that reversals can happen very quickly, over a matter of years instead of millennia.
I've received a lot of flack over my assertions that magnetic reversals can occur in as little as 30 days. I cited the rapid reversals in the lava flows on Steens Mountain as part of my proof, so I'm glad to see this new discovery in Nevada.
“We’re trying to make the case that [the new work] is another record of a superfast magnetic change,” says Bogue, lead author of the paper.
As might be expected, not all experts are convinced.
"The last stable reversal occurred 780,000 years ago," the article continues. "Some geologists argue the Earth is overdue for a reversal and might even be entering one now, as the geomagnetic field has been getting weaker over the past 150 years or more."
http://www.evolutionaryleaps.com/Geomagnetic_field_reverses_in_a_flash.htm
The field is generated by the "sloshing" of the molten core (that's why planets with solid/frozen cores do not have significant magnetic fields).... The field can't collapse for a year....
