2 Quotes Tagged: cosmic-impact

The Younger Dryas impacts, and subsequent sustained cataclysm, changed the face of the earth completely and wrought particularly significant havoc across North America. We have considered the question of huge volumes of meltwater released into the Arctic and Atlantic Oceans from the destabilized ice sheet and looked at the effects on global climate. But keep in mind that those enormous floods also devastated the rich North American mainland to the south, perhaps the best and most bounteous real estate then available anywhere.
This immense and extraordinary deluge, 'possibly the largest flood in the history of the world,' swept away and utterly demolished everything that lay in its path. Jostling with icebergs, choked by whole forests ripped up by their roots, turbulent with mud and boulders swirling in the depths of the current, what the deluge left behind can still be seen in something of its raw form in the Channeled Scablands of the state of Washington today — a devastated blank slate [...] littered with 10,000-ton 'glacial erratics,' immense fossilized waterfalls, and 'current ripples' hundreds of feet long and dozens of feet high.
If there were cities there, before the deluge, they would be gone.
If there was any evidence of anything that we would recognize as technology there, before the deluge, it would be gone.

[The cosmic impact that started the Younger Dryas] marked the end of their story, and the end of an epoch, really. There's not a single Clovis point found anywhere in North America that's above that black mat. They're all in it or below it. And there's not a single mammoth skeleton anywhere in North America that's above it. A huge part of the die-off could have been as a direct result of the impacts themselves, but impacts and airbursts south of the ice cap, particularly as far south as New Mexico, would also have set off wildfires. There's overwhelming evidence that gigantic wildfires raged at the onset of the Younger Dryas — in fact, more soot has been found at the Younger Dryas Boundary than at the Cretaceous-Paleogene Boundary. We did the calculations and it looks like as much as 25 percent of the edible biomass and around 9 percent of the total biomass of the planet was on fire and destroyed within days or weeks of the YDB. So in many areas if the animals weren't killed outright they wouldn't have been able to forage enough food afterwards to survive. The grass would have burned up, leaves on trees were gone. ... And you know, the other thing is that when comet fragments come in they're traveling incredibly fast and they literally punch a hole in the atmosphere. They actually push the air aside and they bring in that super cold from space, and when they explode in the air that cold plume continues to the ground and you literally have things frozen in place if they were close enough to where the plume came down. It's possible they were fried and then frozen all within a matter of seconds.