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

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Discussion Overview

The discussion revolves around the Laschamp geomagnetic field excursion, particularly its causes and implications, including its potential effects on life during the event. Participants explore the relationship between geomagnetic excursions and magnetic field reversals, as well as the relevance of these excursions to megafaunal extinctions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants reference a paper suggesting that the Laschamp excursion is related to normal secular variation and not necessarily indicative of a magnetic field reversal.
  • There is interest in the effects of reduced magnetic field intensity on plant and animal life during the excursion, with one participant expressing intent to research further.
  • A participant proposes a speculative 'Rogue Moon' hypothesis, suggesting that a celestial body could have influenced the Earth's core dynamics during the excursion.
  • Another participant challenges the relevance of linking the Laschamp excursion to megafaunal extinctions, stating that such associations should be supported by scientific literature.
  • Concerns are raised about the appropriateness of discussing unverified speculative ideas, emphasizing adherence to established scientific discourse.

Areas of Agreement / Disagreement

Participants express differing views on the relevance of the Laschamp excursion to megafaunal extinctions and the validity of speculative hypotheses. The discussion remains unresolved regarding the implications of the excursion on life and the acceptance of speculative ideas.

Contextual Notes

Limitations include the lack of consensus on the connection between geomagnetic excursions and biological impacts, as well as the speculative nature of some proposed ideas that are not grounded in published scientific literature.

aspergers@40
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This paper http://www.agu.org/pubs/crossref/2005/2003JB002943.shtml 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
Earth's Magnetic Field[/url]

.
 
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aspergers@40 said:
This paper http://www.agu.org/pubs/crossref/2005/2003JB002943.shtml 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
Earth's Magnetic Field[/url]

.

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
 
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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..
 
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?
 
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).
Greg Bernhardt said:
Overly Speculative Posts:
One of the main goals of PF is to help students learn the current status of physics as practiced by the scientific community; accordingly, Physicsforums.com strives to maintain high standards of academic integrity. There are many open questions in physics, and we welcome discussion on those subjects provided the discussion remains intellectually sound. It is against our Posting Guidelines to discuss, in most of the PF forums or in blogs, new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current professional mainstream scientific discussion. Personal theories/Independent Research may be submitted to our https://www.physicsforums.com/forumdisplay.php?f=146"; Personal theories posted elsewhere will be deleted. Poorly formulated personal theories, unfounded challenges of mainstream science, and overt crackpottery will not be tolerated anywhere on the site. Linking to obviously "crank" or "crackpot" sites is prohibited.
 
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