COMET THEORY FALSE It doesn’t explain the Younger Dryas cold snap, Clovis changes or the mass animal extinction. Most supposed impact indicators at 29 sites are too old or too young to be remnants of an ancient comet that proponents claim sparked climate change at the end of the Ice Age, killed America’s earliest people and caused a mass animal extinction Controversy over what sparked the Younger Dryas, a brief return to near glacial conditions at the end of the Ice Age, includes a theory that it was caused by a comet hitting the Earth. As proof, proponents point to sediments containing deposits they believe could result only from a cosmic impact. Scientists agree that the brief episode at the end of the Ice Age — officially known as the Younger Dryas for a flower that flourished at that time — sparked widespread cooling of the Earth 12.8 kya and that this cool period lasted for 1 ka.. But theories about the cause of this abrupt climate change are numerous. They range from changes in ocean circulation patterns caused by glacial meltwater entering the ocean to the cosmic-impact theory. The cosmic-impact theory is said to be supported by the presence of geological indicators that are extraterrestrial in origin. However a review of the dating of the sediments at the 29 sites reported to have such indicators proves the cosmic-impact theory false, said Meltzer. Meltzer and his co-authors found that only three of 29 sites commonly referenced to support the cosmic-impact theory actually date to the window of time for the Ice Age. The findings, “Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12.8 kya,” were reported May 12, 2014, in the Proceedings of the National Academy of Sciences. “The supposed impact markers are undated or significantly older or younger than 12.8 kya,” report the authors. “Either there were many more impacts than supposed, including one as recently as 5 centuries ago, or, far more likely, these are not extraterrestrial impact markers.” Dating of purported Younger Dryas sites proves unreliable The Younger Dryas Impact Hypothesis rests heavily on the claim that there is a Younger Dryas boundary layer at 29 sites in the Americas and elsewhere that contains deposits of supposed extraterrestrial origin that date to a 300 year span centered on 12.8 kya. The deposits include magnetic grains with iridium, magnetic microspherules, charcoal, soot, carbon spherules, glass-like carbon containing nanodiamonds, and fullerenes with extraterrestrial helium, all said to result from a comet or other cosmic event hitting the Earth. Meltzer and his colleagues tested that hypothesis by investigating the existing stratigraphic and chronological data sets reported in the published scientific literature and accepted as proof by cosmic-impact proponents, to determine if these markers dated to the onset of the Younger Dryas. They sorted the 29 sites by the availability of radiometric or numeric ages and then the type of age control, if available, and whether the age control is secure. The researchers found that three sites lack absolute age control: at Chobot, Alberta, the three Clovis points found lack stratigraphic context, and the majority of other diagnostic artifacts are younger than Clovis by thousands of years; at Morley, Alberta, Canada, ridges are assumed without evidence to be chronologically correlated with Ice Age hills 2 600 kilometers away; and at Paw Paw Cove, Maryland, USA, horizontal integrity of the Clovis artifacts found is compromised, according to that site’s principal archaeologist. The remaining 26 sites have radiometric or other potential numeric ages, but only three date to the Younger Dryas boundary layer. At eight of those sites, the ages are unrelated to the supposed Younger Dryas boundary layer, as for example at Gainey, Michigan, where extensive stratigraphic mixing of artifacts found at the site makes it impossible to know their position to the supposed Younger Dryas boundary layer. Where direct dating did occur, it’s sometime after the 16th century A.D. At Wally’s Beach, Alberta, a radiocarbon age of 10 980 purportedly dates extraterrestrial impact markers from sediment in the skull of an extinct horse. In actuality, the date is from an extinct musk ox, and the fossil yielding the supposed impact markers was not dated, nor is there evidence to suggest that the fossils from Wally’s Beach are all of the same age or date to the Younger Dryas onset. The authors go on to point out that inferences about the ages of supposed Younger Dryas boundary layers are unsupported by replication in more cases than not. In North America, the Ice Age was marked by the mass extinction of several dozen genera of large mammals, including mammoths, mastodons, American horses, Western camels, two types of deer, ancient bison, giant beaver, giant bears, sabre-toothed cats, giant bears, American cheetahs, and many other animals, as well as plants. For more information, smuresearch. Images: (Upper) Native American artifacts. Image Credit: Bill Whittaker/Iowa Office of the State Archaeologist/Creative Commons. (Lower) Clovis peoples artifact. Image Credit: Credit: Underb / Fotolia
Posted on: Wed, 25 Jun 2014 03:29:07 +0000
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