Posted on 10/25/2019 1:17:29 PM PDT by Red Badger
A controversial theory that suggests an extraterrestrial body crashing to Earth almost 13,000 years ago caused the extinction of many large animals and a probable population decline in early humans is gaining traction from research sites around the world.
The Younger Dryas Impact Hypothesis, controversial from the time it was presented in 2007, proposes that an asteroid or comet hit the Earth about 12,800 years ago causing a period of extreme cooling that contributed to extinctions of more than 35 species of megafauna including giant sloths, sabre-tooth cats, mastodons and mammoths. It also coincides with a serious decline in early human populations such as the Clovis culture and is believed to have caused massive wildfires that could have blocked sunlight, causing an "impact winter" near the end of the Pleistocene Epoch.
In a new study published this week in Scientific Reports, a publication of Nature, U of SC archaeologist Christopher Moore and 16 colleagues present further evidence of a cosmic impact based on research done at White Pond near Elgin, South Carolina. The study builds on similar findings of platinum spikes—an element associated with cosmic objects like asteroids or comets—in North America, Europe, western Asia and recently in Chile and South Africa.
"We continue to find evidence and expand geographically. There have been numerous papers that have come out in the past couple of years with similar data from other sites that almost universally support the notion that there was an extraterrestrial impact or comet airburst that caused the Younger Dryas climate event," Moore says.
Moore also was lead author on a previous paper documenting sites in North America where platinum spikes have been found and a co-author on several other papers that document elevated levels of platinum in archaeological sites, including Pilauco, Chile—the first discovery of evidence in the Southern Hemisphere.
"First, we thought it was a North American event, and then there was evidence in Europe and elsewhere that it was a Northern Hemisphere event. And now with the research in Chile and South Africa, it looks like it was probably a global event," he says.
In addition, a team of researchers found unusually high concentrations of platinum and iridium in outwash sediments from a recently discovered crater in Greenland that could have been the impact point. Although the crater hasn't been precisely dated yet, Moore says the possibility is good that it could be the "smoking gun" that scientists have been looking for to confirm a cosmic event. Additionally, data from South America and elsewhere suggests the event may have actually included multiple impacts and airbursts over the entire globe.
While the brief return to ice-age conditions during the Younger Dryas period has been well-documented, the reasons for it and the decline of human populations and animals have remained unclear. The impact hypothesis was proposed as a possible trigger for these abrupt climate changes that lasted about 1,400 years.
The Younger Dryas event gets its name from a wildflower, Dryas octopetala, which can tolerate cold conditions and suddenly became common in parts of Europe 12,800 years ago. The Younger Dryas Impact Hypothesis became controversial, Moore says, because the all-encompassing theory that a cosmic impact triggered cascading events leading to extinctions was viewed as improbable by some scientists.
"It was bold in the sense that it was trying to answer a lot of really tough questions that people have been grappling with for a long time in a single blow," he says, adding that some researchers continue to be critical.
The conventional view has been that the failure of glacial ice dams allowed a massive release of freshwater into the north Atlantic, affecting oceanic circulation and causing the Earth to plunge into a cold climate. The Younger Dryas hypothesis simply claims that the cosmic impact was the trigger for the meltwater pulse into the oceans.
In research at White Pond in South Carolina, Moore and his colleagues used a core barrel to extract sediment samples from underneath the pond. The samples, dated to the beginning of the Younger Dryas with radiocarbon, contain a large platinum anomaly, consistent with findings from other sites, Moore says. A large soot anomaly also was found in cores from the site, indicating regional large-scale wildfires in the same time interval.
In addition, fungal spores associated with the dung of large herbivores were found to decrease at the beginning of the Younger Dryas period, suggesting a decline in ice-age megafauna beginning at the time of the impact.
"We speculate that the impact contributed to the extinction, but it wasn't the only cause. Over hunting by humans almost certainly contributed, too, as did climate change," Moore says. "Some of these animals survived after the event, in some cases for centuries. But from the spore data at White Pond and elsewhere, it looks like some of them went extinct at the beginning of the Younger Dryas, probably as a result of the environmental disruption caused by impact-related wildfires and climate change."
Additional evidence found at other sites in support of an extraterrestrial impact includes the discovery of meltglass, microscopic spherical particles and nanodiamonds, indicating enough heat and pressure was present to fuse materials on the Earth's surface. Another indicator is the presence of iridium, an element associated with cosmic objects, that scientists also found in the rock layers dated 65 million years ago from an impact that caused dinosaur extinction.
While no one knows for certain why the Clovis people and iconic ice-age beasts disappeared, research by Moore and others is providing important clues as evidence builds in support of the Younger Dryas Impact Hypothesis.
"Those are big debates that have been going on for a long time," Moore says. "These kinds of things in science sometimes take a really long time to gain widespread acceptance. That was true for the dinosaur extinction when the idea was proposed that an impact had killed them. It was the same thing with plate tectonics. But now those ideas are completely established science."
More information: Christopher R. Moore et al. Sediment Cores from White Pond, South Carolina, contain a Platinum Anomaly, Pyrogenic Carbon Peak, and Coprophilous Spore Decline at 12.8 ka, Scientific Reports (2019). DOI: 10.1038/s41598-019-51552-8 Journal information: Scientific Reports
Core samples from White Pond near Elgin, South Carolina, show evidence of platinum spikes and soot indicative of an impact from an asteroid or comet. Credit: University of South Carolina
Those damn polluting extraterrestrials! How dare they?
This not only explains the large-scale extinction, it’s probably the source of the Great Flood myths around the world. If as they believe the comet made a number of impacts on the arctic ice cap, sea level would have risen almost 400 feet almost overnight.
Isn’t this around the time of the quick-frozen Beresovka mammoth?
There is a cave in Florida, now under water that they have found ashes of a campfire and burnt bones from animals of the time.....................
The Gulf of Mexico looks like a giant water filled impact crater
The flood stories more closely correlate with events of 7000 years ago when the rising sea levels flooded the north sea, the baltic sea and the black sea.
Kinda stupid to call it myth and then state 400 foot water rise..
Just saying
The problem with this story is that the previous ice age lasted around 80,000 years before it ended. It was shortly after that when the asteroid hit. So then, how did these animals survive the ice age, only to become extinct after just a short period of warming?
The data I’ve seen is that the Younger Dryas cold was no worse than the worst of the ice age.
Aliens. I’m not saying it was aliens but it was aliens.
Plausibly, the earlier Ice Age was due to relatively slow cyclical changes in earth’s orbit that permitted adaptation and survival. A more abrupt transition due to a comet or asteroid impact like the Younger Dryas would have been more challenging.
Sounds kinda like Worlds in Collision is a book by Russian-American independent scholar Immanuel Velikovsky published in 1950. The book postulates that around the 15th century BC, the planet Venus was ejected from Jupiter as a comet or comet-like object and passed near Earth (an actual collision is not mentioned). wiki
It was probably in Canada. The resulting deluge caused the glaciers to melt and run south into Baja and the Gulf of Mexico.
It also caused ice dams to form near the Black Sea, which ultimately burst, washing down through the Middle East.
The black mat exists from California to Belgium and down to South America which is evidence of a massive firestorm in North America following the impact. The non burrowing animals in the open probably perish immediately while some small groups in protected valleys may have survived but the food source was gone for a couple of seasons for sure.
According to the Book of Revelation there will be an impact by an asteroid or comet that will make the waters of the earth poisonous. Some comets are completely composed of cyanide. That’s the way I interpret it anyway.
What happens after an extensive volcanic eruption?
Lots and lots of ash thrown into the atmosphere.
When Mt St Helens erupted, day light turned to night light in the surrounding areas. The museum near Mt St Helens has great videos showing all the aftermaths from the eruption.
Ditto when Krakatoa erupted in SE Asia, the darkening effect lasted long time. Which then leads what would happen if a giant asteroid big enough to cause crater the size of Gulf of Mexico. Yeah a nuclear winter lasting months. Those large Dinosaurs were cold blooded animals like Crocs are. They become immobile with cold. They had no energy to hunt for food. Thus they may have just starved to death.
The small mammals of that era on the other hand were warm blooded animals and can regulate their body temp better and many survived. Try this experiment. Place a gecko lizard in a jar (those are ubiquitous here in Florida and they eat insects and have no teeth and are cute) and place the jar in your fridge. Then catch a mouse and do the same thing. The cold blooded gecko will lie immobile and asleep. The mouse will be awake and respond to opening the fridge. That is the difference between cold blooded and warm blooded animals.
When the big herbivores died, so did the predators, including many humans.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.