3 ms·
The Younger Dryas Impact Hypothesis is not quite confirmed, but is probably going to be generally accepted within the next few years. The most recent review I'm
by AlotOfReading 4y ago
The Younger Dryas Impact Hypothesis is not quite confirmed, but is probably going to be generally accepted within the next few years. The most recent review I'm aware of is Sweatman's 2021 [1] article arguing that we're already there. He makes a very relevant callout in the paper as well:
The proposal is that this impact triggered the Younger Dryas (YD) cooling and contributed to the end-Pleistocene megafaunal extinctions and human cultural changes. Equally, it should be clear that Firestone et al. (2007) are not claiming that the impact event itself wiped out many genera of megafauna or an entire human culture in an instant.
Of course, it's pretty obvious that the late quaternary extinction events weren't solely related to any particular impact event, if for no other reason than that many of the extinctions pre-date the impact and we can see the decline in North American megafaunal populations long before it.
[1] https://doi.org/10.1016/j.earscirev.2021.103677 https://doi.org/10.1016/j.earscirev.2021.103677
- ch4s3 4y agoThanks, that’s pretty interesting. I’ll have to read that link later.
- ncmncm 4y ago> we can see the decline in North American megafaunal populations long before People used to say that about the K-T event, too. They later stopped saying it. It is well established that and when the bolide strike occurred, coinciding with lots of interesting phenomena -- extinctions, climate hiccup, continent-spanning fires, platinum dust. Did it cause them all? That takes more work to establish. But we don't have any competing hypothesis. https://sci-hub.se/10.1086/695703 https://sci-hub.se/10.1086/695703 A catastrophically big volcanic eruption in Europe only a century or two before the bolide strike seemed like it might have caused some things, but the timing does not now seem to match. Something similar is true of the K-T boundary, except even overwhelmingly more-catastrophic eruptions blanketed India, and I don't think we know for sure which came first. It is just possible the bolide strike triggered the eruptions. (Certainly the eruption didn't cause the strike.)
- AlotOfReading 4y agoIt's not really disputed that there were quaternary extinctions prior to the YD boundary, nor that megafauna survived for quite awhile after the boundary. There's a whole wikipedia article on this, aptly titled 'Quaternary Extinction Event' [1]. [2] (from the supplemental data of [3] has a nice list in table 1. [1] https://en.wikipedia.org/wiki/Quaternary_extinction_event https://en.wikipedia.org/wiki/Quaternary_extinction_event [2] https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-021-27439-6/MediaObjects/41467_2021_27439_MOESM1_ESM.pdf https://static-content.springer.com/esm/art%3A10.1038%2Fs414... [3] https://doi.org/10.1038/s41467-021-27439-6 https://doi.org/10.1038/s41467-021-27439-6