Via Reynolds, "Asteroid shower on the Earth-Moon system immediately before the Cryogenian period revealed by KAGUYA". KAGUYA is a crater-survey on the Moon. "Cryogenian" is that ice age starting 720 Mya.
... but the craters are dated 800 Mya. That is... NOT "immediately before". That's a swing of years (far) exceeding 66 Mya between Chicxulub and us. The authors do indeed offer a ridiculously wide error-bar, 797 ± 52 Mya.
More interestingly, eight craters cluster 660 Mya. Also late in the Cryogenian, and these didn't hit Earth; but if they had cousins, perhaps enough to keep us frosty.
Also of note is that Earth's phosphorus-cycle shifted around 800 Mya. That, rather than cold, seems more on point.
BETTER FIT 7/30: Volcanoes.
No comments:
Post a Comment