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Deep-sea sediment records of the Laschamp geomagnetic field excursion (41kya)

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aspergers@40
#1
Jan14-10, 06:13 AM
P: 61
This paper Deep-sea sediment records of the Laschamp geomagnetic field excursion (∼41,000 calendar years before present) concludes that the narrow Laschamps excursion event, or class I excursions in general, are more closely related to normal secular variation and are not necessarily a prelude to magnetic field reversal. So what are they and what causes them? The geomagnetic field suffered for some time and so one would imagine that life did as well: "magnetic field intensities less than 10% of normal that persisted for almost 2000 years". How relevant is this event to the megafaunal extinctions for example?
Wikipedia Geomagnetic Excursions
Wikipedia Earth's Magnetic Field

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sylas
#2
Jan14-10, 09:08 AM
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Quote Quote by aspergers@40 View Post
This paper Deep-sea sediment records of the Laschamp geomagnetic field excursion (∼41,000 calendar years before present) concludes that the narrow Laschamps excursion event, or class I excursions in general, are more closely related to normal secular variation and are not necessarily a prelude to magnetic field reversal. So what are they and what causes them? The geomagnetic field suffered for some time and so one would imagine that life did as well: "magnetic field intensities less than 10% of normal that persisted for almost 2000 years". How relevant is this event to the megafaunal extinctions for example?
Wikipedia Geomagnetic Excursions
Wikipedia Earth's Magnetic Field

.
We should not be bothering with alleged relevance to megafaunal extinctions unless that association appears somewhere in the scientific literature, and I am pretty confident it doesn't.

Discussion of the ideas in the paper, which are to do with physical causes of magnetic field excursions, are fine.

Cheers -- sylas
aspergers@40
#3
Jan14-10, 10:18 AM
P: 61
Okay, but I'm interested in the effects of a 10% magnetic field for 2000 years on the plant and animal life. I'll google some more papers I guess..

aspergers@40
#4
Jan15-10, 08:34 AM
P: 61
Deep-sea sediment records of the Laschamp geomagnetic field excursion (41kya)

Am I allowed to speculate on a 'Rogue Moon' hypothesis (or any 0.5 moon object), whose flyby exerted a gravitational influence which disrupted the dynamics of the Earth's core some 41,000 years ago?
sylas
#5
Jan15-10, 08:56 AM
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Check the Guidelines. Speculations about a rogue moon would be against this section, because they have not been published in the scientific literature (and never will be, frankly).
Quote Quote by Greg Bernhardt, in Physics Forums Global Guidelines View Post
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