The Laschamp Excursion

20 Feb 2021

Gary sent in a link to https://theconversation.com/we-found-the-first-australian-evidence-of-a-... ... but the story can be found elsewhere. Evidence has been found of the Laschamp excursion in Australia - and it confirms it was a complete reversal event [lasting several thousand years]. It occurred around 40,000 years ago which is well documented elsewhere, too. This is an interesting date as C14 dating methodology has problems dating anything prior to 40,000 [but Bayesian methodology has extended that a bit by using less accurate techniques, and in so doing claims to have pushed the boundary back a bit more]. Averaging is a bit like modelling. You get out what you put in. It's impossible to get out anything that isn't put in. The really nice thing about this is that the authors are quick to make a link with the disappearance of the Neanderthals, and a great die-off of land animals, on a global basis, at the same point in time. The headline implies this is the first time the Laschamp has been found in Australia. No surprise there if they haven't been looking. The point is they have now looked and discovered the evidence. This was a complete magnetic pole reversal [nothing to do with the geographical poles]. We don't really know what that entails and what it would mean to living things. Lots of conjecture by comments and authors. A lot of it negative. As catastrophists we may note that Firestone, West and Warwick-Smith were writing about this ages ago, in their book 'The Cycle of Cosmic Catastrophes'. It is nothing new. Not only that but the Laschamp event has been known for a long time. In Australia we had the Lake Mungo Excursion, dated around 33,000 years ago, leading to the idea of a twin batch of cosmic disasters between 40 and 30,000 years ago. It is interesting to note that a magnetic reversal occurred at the same time. Why that should be so is unknown. However, it does open a door and allow mainstream spokespeople to refute the catastrophe by saying a magnetic reversal is not a disaster. Even though the magnetic poles trip over, and later, reversed themselves.

There are of course problems glossed over by the early critics and this is that a weakening of the magnetic field implies a greater input of cosmic rays from outside our solar system. Firestone et al toyed with the idea that a supernova was involved. Supernovas are also a mainstream theory but they are sadly lacking as far as actual evidence of one affecting earth is concerned. It is thought that the explosion of a star would cause lots of damaging cosmic rays to fan out across the universe and by rights the earth should have experienced such an event on more than one occasion. Always supposing supernovas are real and not an invention of the minds of cosmologists. Earth's magnetic field is designed to keep not only cosmic rays at bay but the solar wind too. The idea is to check high energy particles. The Laschamp reversal was first discovered in France, in an old lava flow [that left the signature of the earth's magnetisim when the lava hardened after the eruption]. Subsequently, it was found elsewhere. For example, the Russians have done considerable research into excursion events, and there were many of them. Most were not  full reversals and therefore there is another point to mull over. What might cause an excursion that reverts back to normal after a couple of centuries, or less, and a full reversal event?

At https://phys.org/news/2021-02-humans-tasmania-spectacular-auroras.html ... focusses on the fantastic auroras that would have been seen during the magnetic reversal event, 41000 years ago 

At https://phys.org/news/2021-02-ancient-relic-earth-history-years.html ... it begins with pushing the date back to 42,000 years ago, and evidence of a major bout of climate shifts coincident with the reversal. This is not  surprising as Chris Turney, one of the authors of the study, has written a couple of useful books on paleo-climate switches. What is interesting is that the authors go on to link the reversal to environmental change [the beginning of the arid phase in Australia] as well as a mass die-off [described as an extinction event in the  press release]. In other words, an event which involved an electrical storm, widespead auroral phenomena, and an increase in cosmic radiation. Sounds a bit like a catastrophic. Wonder what the Dreaming has to say about it. We do know that Aborigines are fearful of aurora outbreaks - and this may have an ancient origin. Perhaps. From the press release it is not clear if the scientists themselves think the magnetic reversal was to blame for all these things or recognised they were connected in an unknown manner. Worth browsing the actual paper if you can get hold of it. In addition, we are told there was a spike in global C14 levels. Is that the reason why C14 methodology came to the bufferes when trying to date organic matter around 40,000 years ago. Sounds like an enviable C14 injection into the atmosphere.

One nicer outcome of this might be that Aborigines will cease to be blamed for the disappearance of Australian megafauna, one of mainstream's pet theories to disappear the idea of a catastrophic event. One may also wonder what the geographical poles were doing during the magnetic reversal. The paleo-climatic changes will also be worth sifting through as they are clues to just how and why the environmental changes came into place.