http://www.livescience.com/51688-ancient-huts-earth-magnetic-reversal.html
The fiery demise of ancient huts in southern Africa 1,000 years ago left clues to understanding a bizarre weak spot in the Earth's magnetic field — and the role it plays in the magnetic poles' periodic reversals.
Patches of ground where huts were burned down in southern Africa contain a key mineral that recorded the magnetic field at the time of each ritual burning. Those mineral records teach researchers more about a weird, weak patch of Earth's magnetic field called the South Atlantic Anomaly and point the way toward a possible mechanism for sudden reversals of the field.
"It has long been thought reversals start at random locations, but our study suggests this may not be the case," John Tarduno, a geophysicist from the University of Rochester in New York and lead author of the paper, said in a statement. [How Earth's Magnetic Field Shielded Us from 2014 Solar Storm].
Tarduno told Space.comin an interview that data
from the huts suggest that the strange weak patch "forms, and it decays away, and it forms, and it decays away; eventually, one might form and get really large, and then we might actually have a geomagnetic reversal.
More at site
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I wonder how many times this has happened?
The fiery demise of ancient huts in southern Africa 1,000 years ago left clues to understanding a bizarre weak spot in the Earth's magnetic field — and the role it plays in the magnetic poles' periodic reversals.
Patches of ground where huts were burned down in southern Africa contain a key mineral that recorded the magnetic field at the time of each ritual burning. Those mineral records teach researchers more about a weird, weak patch of Earth's magnetic field called the South Atlantic Anomaly and point the way toward a possible mechanism for sudden reversals of the field.
"It has long been thought reversals start at random locations, but our study suggests this may not be the case," John Tarduno, a geophysicist from the University of Rochester in New York and lead author of the paper, said in a statement. [How Earth's Magnetic Field Shielded Us from 2014 Solar Storm].
Tarduno told Space.comin an interview that data
from the huts suggest that the strange weak patch "forms, and it decays away, and it forms, and it decays away; eventually, one might form and get really large, and then we might actually have a geomagnetic reversal.More at site
________________________________________________________________________________
I wonder how many times this has happened?