New paper from the Comet Research Group confirms comet impact
The latest paper, published in Scientific Reports here, from the Comet Research Group and colleagues in Chile provides yet more evidence the Younger Dryas event was a comet impact.
Like their others, this new paper is extensive and detailed, this time providing 10 different streams of evidence for the Younger Dryas boundary layer at Pilauco, Chile. It means severe effects from this event were felt across nearly half the world's land surface, and perhaps more.
These new results are especially interesting for a couple of reasons, in my view. We already knew the Younger Dryas event happened - there is no doubt about that. We also know it caused the Younger Dryas mini ice-age - a period of around 1,300 years from 12,900 to 11,600 BC - when northern hemisphere temperatures plummeted by 10 to 15 degrees C. The evidence for this, in terms of geochemistry, astronomy and archaeology summarized in Prehistory Decoded, is overwhelming. So in that respect, this new paper changes very little.
However, this new work suggests there were probably multiple impacts at this time, pointing firmly towards the culprit being a fragmented comet. The key finding, I think, is that some of the microspheres found at the boundary layer are very rich in chromium. This is unique to this site and points strongly towards a local impactor that vaporised local rock strata rich in this metal. Another possibility is that this local impact might be a secondary impact - where space-borne rock ejected from the initial impact site falls back to Earth at a distant site. But my impression is that this is unlikely given the vast distances involved.
Another important insight this new work provides is that the South American megafauna were likely exterminated by the impact itself and its immediate consequences, such as wildfires and loss of vegetation, rather than climate change. The reason being that the paper shows that climate (temperatures) increased, rather than dropped precipitously, at this southern latitude in the aftermath of the event. So, at least at this locale, climate change is probably not the main killer. The event itself did the damage. And if this is true for this region, then it likely holds for North America too.
Importantly, a comet impact points strongly towards the Taurid meteor stream as the culprit - as recorded at Gobekli Tepe.
This evidence for multiple comet fragments aligns with the archaeological evidence.
ReplyDeleteA single asteroid impact would have been difficult to associate with a particular direction in the sky, or even to attribute to celestial origin.
Multiple, conspicuous bolides from a specific radiant over a prolonged period would provide much greater incentive and opportunity to record and transmit knowledge of the events.
Yes, great point. The warning signs might have appeared every 33 years, with close approaches until finally the big day.
ReplyDeleteAlso makes the religion much more understandable. Imagine seeing your doom approach over your lifetime, close approaches getting ever closer. What would you do? What could you do? You'd try anything. And make sure everyone knew.
DeleteThe whole world with the same story - the same reference points. Makes cooperation among different people afterwards more likely perhaps.
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