9 Quotes Tagged: younger-dryas

Professor Napier and his colleague Victor Clube, formerly dean of the Astrophysics Department at Oxford University, go so far as to describe the 'unique complex of debris' within the Taurid stream as 'the greatest collision hazard facing the earth at the present time.' Coordination of their findings with those of Allen West, Jim Kennett, and Richard Firestone, as led both teams — the geophysicists and the astronomers — to conclude that it was very likely objects from the then much younger Taurid meteor stream that hit the earth around 12,800 years ago and caused the onset of the Younger Dryas. These objects, orders of magnitude larger than the one that exploded over Tunguska, contained extraterrestrial platinum, and what the evidence from the Greenland ice cores seems to indicate is an epoch of 21 years in which the earth was hit every year, with the bombardments increasing annually in intensity until the fourteenth year, when they peaked and then began to decline before ceasing in the twenty-first year.

Thomas Crowley and Gerald North, oceanographers at Texas A&M University, describe the melting of the great ice-sheets at the end of the last Ice Age as 'one of the most rapid and extreme examples of climate change recorded in the geologic record'.

A 24,000-year sequence recorded in a marine core from the Santa Barbara Basin, off the coast of California, exhibits the highest peak in biomass burning precisely at the onset of the Younger Dryas. ... This anomalously high peak correlates with intense biomass burning documented from the nearby Channel Islands. ... The peak also coincides with the extinction of pygmy mammoths on the islands and with the beginning of an apparent 600-800-year gap in the archaeological record, suggesting a sudden collapse in island human populations.

The black mat formed on top of the layer of proxies,' Allen replies. 'Down here it has a lot of charcoal in it. But it also has algal remains so it's not just fire. The Younger Dryas changed the climate and made the area much wetter. Algae began to grow along the edges of the lakes.' He puts a hand on the black stripe along the arroyo wall: 'So the remains of about 1,000 years of dead algae, charcoal, and a lot of other stuff are all embedded in here, and at the bottom of it, where the impact happened, we find iridium, platinum, and a layer of melted spherules where the temperatures must have been so high that they would have melted a modern car into a pool of metal.

As the discoverer and principal excavator of Murray Springs, [...] Haynes deserves credit for drawing attention to a very curious aspect of the site — a distinct dark layer of soil draped 'like a shrink-wrap,' as Allen West puts it, over the top of the Clovis remains and of the extinct megafauna — including Eloise.
Haynes has identified this 'black mat' (his term) not only at Murray Springs but at dozens of other sites across North America, and was the first to acknowledge its clear and obvious association with the Late Pleistocene Extinction Event. he speaks of the 'remarkable circumstances' surrounding the event, the abrupt die-off on a continental scale of all large mammals 'immediately before deposition of the ... black mat,' and the total absence thereafter of 'mammoth, mastodon, horse, camel, dire wold, American lion, tapir and other [megafauna], as well as Clovis people.'
Haynes notes also that 'The basal black mat contact marks a major climate change from the warm dry climate of the terminal Allerod to the glacially cold Younger Dryas.'
From roughly 18,000 years ago, and for several thousand years thereafter, global temperatures had been slowly but steadily rising and the ice sheets melting. Our ancestors would have had reason to hope that earth's long winter was at last coming to an end and that a new era of congenial climate beckoned. This process of warming became particularly pronounced after about 14,500 years ago. Then suddenly, around 12,800 years ago, the direction of climate change reversed and the world turned dramatically, instantly cold — as cold as it had been at the peak of the Ice Age many thousands of years earlier. This deep freeze — the mysterious epoch now known as the Younger Dryas — lasted for approximately 1,200 years until 11,600 years ago, at which point the climate flipped again, global temperatures shot up rapidly, the remnant ice sheets melted and collapsed into the oceans, and the world became as warm as it is today.

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.

In North America the evidence is that hunter-gatherers bounced back quite successfully within less than a millennium of the onset of the Younger Dryas, and thereafter there is a thin but fairly continuous archaeological record. What is mysterious is not so much the early appearance of mound-building in this new age — perhaps as early as 8,000 years ago, as we've seen — or the sophistication of sites such as Watson Brake 5,500 years ago, nor even their obvious astronomical and geometrical connections to later vast earthworks such as Moundville and Cahokia, but that in this early monumental architecture of the New World memes of geometry, astronomy, and solar alignments consistently appear that are also found in the early monumental architecture of the Old World at iconic sites such as Stonehenge and the Great Pyramid of Giza. A tremendous leap forward in agricultural know-how, coupled with the sudden uptake of eerily distinctive spiritual ideas concerning the afterlife journey of the soul, also often accompanies the architectural memes. It's therefore hard to avoid the impression that some kind of 'package' is involved here.

In the case of the Younger Dryas, the jeopardy that humanity faced was not from nuclear missiles but from the incoming fragments of a disintegrating giant comet, traveling at tens of kilometers per second, with the larger fragments as deadly as hundreds of nuclear warheads. Indeed, it is estimated that the total explosive power of the comet fragments that struck the earth in repeated episodes over a period of 21 years some 12,800 years ago would have been of the order of 10 million megatons — 1,000 times greater than all the nuclear devices stockpiled in the world today.