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The Laschamp or Laschamps event was a geomagnetic excursion (a short reversal of the Earth's magnetic field). It occurred between 42,200 and 41,500 years ago, during the end of the Last Glacial Period. It was discovered from geomagnetic anomalies found in the Laschamps and Olby lava flows near Clermont-Ferrand, France in the 1960s. [1] [2]
The rate of reversals in the Earth's magnetic field has varied widely over time. Around 72 Ma , the field reversed 5 times in a million years. In a 4-million-year period centered on 54 Ma , there were 10 reversals; at around 42 Ma , 17 reversals took place in the span of 3 million years.
A geomagnetic excursion, like a geomagnetic reversal, is a significant change in the Earth's magnetic field.Unlike reversals, an excursion is not a long-term re-orientation of the large-scale field, but rather represents a dramatic, typically a (geologically) short-lived change in field intensity, with a variation in pole orientation of up to 45° from the previous position.
The last time the poles reversed was 780,000 years ago so it’s not like we have a record for this. Turns out 780,000 years is over double the time Earth usually takes between flips.
The geographic poles are defined by the points on the surface of Earth that are intersected by the axis of rotation. The pole shift hypothesis describes a change in location of these poles with respect to the underlying surface – a phenomenon distinct from the changes in axial orientation with respect to the plane of the ecliptic that are caused by precession and nutation, and is an ...
Neanderthals died out 42,000 years ago as Earth’s magnetic poles flipped, scientists claim ... the flipping of Earth’s magnetic poles around 40,000 B.C. is a likely reason the Neanderthals ...
The geomagnetic poles move over time because the geomagnetic field is produced by motion of the molten iron alloys in the Earth's outer core. (See geodynamo .) Over the past 150 years, the poles have moved westward at a rate of 0.05° to 0.1° per year and closer to the true poles at 0.01° per year.
A magnet's North pole is defined as the pole that is attracted by the Earth's North Magnetic Pole when the magnet is suspended so it can turn freely. Since opposite poles attract, the North Magnetic Pole of the Earth is really the south pole of its magnetic field (the place where the field is directed downward into the Earth).