Younger Dryas: Canadian Comet Impact Triggered Climate Shift?

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In summary, Mukul Sharma of Dartmouth believes that a large meteor impact in Quebec around 12900 years ago may have been the primary cause of the Younger Dryas climate shift. This theory also suggests possible connections to the extinction of megafauna and the development of agriculture by Native American peoples. While the paper is yet to be published and fully reviewed, it presents an intriguing hypothesis worth considering.
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jim mcnamara
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Pre-publish article:

http://www.theregister.co.uk/2013/0...d_for_triggering_younger_dryas_climate_shift/

Mukul Sharma of Dartmouth claims there is very good evidence that the extremely rapid draining of Lake Agassiz about 12900ya is only a partial contributor to the cold period (Younger Dryas) that started 12900ya. There is geological evidence of a large meteor impact in Quebec at the same time. He claims that is the primary cause.

The register article mentions other posited effects: start of the Megafauna extinction, an increase agriculture by Native American peoples.

I think we should reserve judgement until the paper is out. But a "head's up" is in order.
This will be out shortly in PNAS, which is kind of home to somewhat speculative articles sometimes. IMO. Obviously they are refereed papers.
 
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Thank you Jim!
 
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I find this theory very intriguing and plausible. The idea that a large meteor impact in Quebec could have triggered the Younger Dryas period is definitely worth exploring. It's interesting to consider how this event could have affected not only the climate, but also the extinction of megafauna and the development of agriculture by Native American peoples. I agree that we should wait for the paper to be published and thoroughly reviewed before making any conclusions, but I'm definitely looking forward to reading it. Thank you for sharing this article and bringing this theory to our attention.
 

FAQ: Younger Dryas: Canadian Comet Impact Triggered Climate Shift?

1. What is the Younger Dryas period?

The Younger Dryas was a sudden cooling period that occurred approximately 12,900 years ago, following the end of the last ice age. It lasted for about 1,300 years and is named after a wildflower called Dryas octopetala, which was common during this time.

2. How was the Younger Dryas triggered?

The most widely accepted theory is that a comet or asteroid impact in Canada triggered the Younger Dryas period. This impact would have caused widespread wildfires and dust to be released into the atmosphere, blocking out the sun's rays and causing a cooling effect.

3. What evidence supports the comet impact theory?

Several pieces of evidence support the comet impact theory, including the discovery of nanodiamonds and microspherules in sediment layers from the Younger Dryas. These are thought to be impact markers and are not found in previous or subsequent sediment layers.

4. What effects did the Younger Dryas have on the Earth's climate?

The Younger Dryas period caused a significant drop in global temperatures, with some regions experiencing a drop of up to 10 degrees Celsius. This led to the expansion of glaciers and ice sheets, and changes in vegetation and animal populations. It also had a significant impact on human societies, with a possible connection to the extinction of the Clovis culture in North America.

5. How did the Earth recover from the Younger Dryas?

The Earth gradually warmed up and recovered from the Younger Dryas period. This was likely due to a combination of factors, including changes in ocean currents and the gradual removal of dust and ash from the atmosphere. The end of the Younger Dryas also marked the beginning of the current interglacial period, known as the Holocene.

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