Mammoth extinction event
May 27, 2013 22:59:17 #
Fascinating article: "evidence of a catastrophic meteoric or cometary explosion about 13,000 years ago was the Chobot site at Buck Lake, Alta."
http://www.canada.com/Alberta+couple+backyard+fuels+major+scientific+debate+over+mammoth+extinction+event/8441316/story.html
A Canadian couples archeological retirement project at their lakeside cottage in Alberta has produced artifacts that are now at the centre of one of sciences most controversial debates: whether a massive comet or meteorite struck a glacier-encased Hudson Bay about 13,000 years ago, wiped out the mammoths and other Ice Age megafauna and destroyed the Clovis culture that represented the first major wave of human migration in the New World.
The hotly disputed theory was recently challenged by a 16-member research team from the United States, Britain and Belgium, which published a major study in February concluding that the odds of a four-kilometre-wide comet exploding across the Laurentide Ice Sheet that covered ancient Canada are infinitesimal given the lack of clear evidence, such as layers of so-called shocked rocks and minerals transformed by an Earth-shaking mega-blast.
No impact craters of the appropriate size and age are known, and no unambiguously shocked material or other features diagnostic of impact have been found to prove the theory, those authors stated in monograph published by the American Geophysical Union. The climatological, paleontological and archeological events that the (proponents) are attempting to explain are not unique, are arguably misinterpreted and do not require an impact.
But last week, a team of 29 scientists from the U.S., Mexico, the Netherlands, Germany and the Czech Republic contradicted the February findings in a new, pro-impact study published online in the Proceedings of the National Academy of Sciences. And among the 18 archeological or geological hotspots around the world that the researchers identified as having evidence of a catastrophic meteoric or cometary explosion about 13,000 years ago was the Chobot site at Buck Lake, Alta.
Located between Calgary and Edmonton, the site was named for an immigrant couple from the former Czechoslovakia Anton and Maria Chobot who spent three decades collecting thousands of prehistoric aboriginal artifacts, animal bones and other remains at their Buck Lake property after moving into a cottage there in the early 1980s.
Sadly, the new PNAS study was published just three days before Anton Chobot died Friday at age 92. His son, Igor, told Postmedia News that the family is very proud of the archeological legacy his parents have left the world after spending more than 30 years pursuing their labour of love at Buck Lake excavating ancient traces of some of Canadas earliest known aboriginal inhabitants, preserving the artifacts for posterity and sharing their findings with scientists.
An area of Alberta east of the Rockies has long been identified as part of the ice-free corridor through which some of the earliest indigenous people in North America having crossed into this continent from Siberia via the dried-up Bering Strait migrated southward at the end of the last Ice Age.
The Chobot site includes a layer of dirt containing approximately 13,000-year-old Clovis points chiseled stone spear tips used to hunt woolly mammoths and other large Ice Age game that appear just below a thin, black mat of charred material. The authors of the U.S.-led PNAS paper believe the charred layer represents the fiery fallout of a massive extraterrestrial impact that abruptly ended the Clovis culture, kick started the extinction of mammoths, sabre-toothed cats and a host of other prehistoric creatures and wreaked havoc on global climate, initiating a 1,000-year cooling known as the Younger Dryas.
Chobot and each of the 17 other sites in North and South America, Europe and the Middle East that were examined by researchers for the PNAS study contains nanodiamonds or iron-rich spherules microscopic globular deposits often associated with an extinction-level cosmic collision.
Impact-related spherules have long been considered one of the most distinctive proxies in support of this hypothesis, the researchers state in the newly published paper. However, despite increasing evidence for (Younger Dryas Boundary) peaks in impact spherules, their presence and origin remain disputed.
But citing the February paper, the PNAS authors argue that their rival researchers neglected nine reliable studies showing significant YDB spherule abundances at about the same layer of approximately 13,000-year-old deposits.
We here present the results of one of the most comprehensive investigations of spherules ever undertaken to address questions of geochemical and morphological characteristics, distribution, origin, and processes involved in the formation of YDB spherules, the scientists state in the newly published paper.
This finding precludes all but a high-temperature cosmic impact event for the spherules, co-author James Kennett, a University of California Santa Barbara earth scientist, said in a summary of the PNAS study.
The climate changed rapidly and profoundly, added fellow co-author Kenneth Tankersley, an assistant professor of anthropology and geology at the University of Cincinnati. And coinciding with this very rapid global climate change (were) mass extinctions.
Two other co-authors of the PNAS study Lawrence Berkeley National Laboratory scientist Richard Firestone and private Arizona geoscientist Allen West recounted a visit to the Chobot site in their 2006 book The Cycle of Cosmic Catastrophes: How a Stone-Age Comet Changed the Course of World Culture.
They heaped praise in their book on the remarkable couple from Alberta.
For years, they have carried on a major amateur excavation of an important archeological site, without professional help and without outside funding, they wrote. While the outside world paid little attention, they have amassed a museum-quality collection of prehistoric artifacts.
http://www.canada.com/Alberta+couple+backyard+fuels+major+scientific+debate+over+mammoth+extinction+event/8441316/story.html
A Canadian couples archeological retirement project at their lakeside cottage in Alberta has produced artifacts that are now at the centre of one of sciences most controversial debates: whether a massive comet or meteorite struck a glacier-encased Hudson Bay about 13,000 years ago, wiped out the mammoths and other Ice Age megafauna and destroyed the Clovis culture that represented the first major wave of human migration in the New World.
The hotly disputed theory was recently challenged by a 16-member research team from the United States, Britain and Belgium, which published a major study in February concluding that the odds of a four-kilometre-wide comet exploding across the Laurentide Ice Sheet that covered ancient Canada are infinitesimal given the lack of clear evidence, such as layers of so-called shocked rocks and minerals transformed by an Earth-shaking mega-blast.
No impact craters of the appropriate size and age are known, and no unambiguously shocked material or other features diagnostic of impact have been found to prove the theory, those authors stated in monograph published by the American Geophysical Union. The climatological, paleontological and archeological events that the (proponents) are attempting to explain are not unique, are arguably misinterpreted and do not require an impact.
But last week, a team of 29 scientists from the U.S., Mexico, the Netherlands, Germany and the Czech Republic contradicted the February findings in a new, pro-impact study published online in the Proceedings of the National Academy of Sciences. And among the 18 archeological or geological hotspots around the world that the researchers identified as having evidence of a catastrophic meteoric or cometary explosion about 13,000 years ago was the Chobot site at Buck Lake, Alta.
Located between Calgary and Edmonton, the site was named for an immigrant couple from the former Czechoslovakia Anton and Maria Chobot who spent three decades collecting thousands of prehistoric aboriginal artifacts, animal bones and other remains at their Buck Lake property after moving into a cottage there in the early 1980s.
Sadly, the new PNAS study was published just three days before Anton Chobot died Friday at age 92. His son, Igor, told Postmedia News that the family is very proud of the archeological legacy his parents have left the world after spending more than 30 years pursuing their labour of love at Buck Lake excavating ancient traces of some of Canadas earliest known aboriginal inhabitants, preserving the artifacts for posterity and sharing their findings with scientists.
An area of Alberta east of the Rockies has long been identified as part of the ice-free corridor through which some of the earliest indigenous people in North America having crossed into this continent from Siberia via the dried-up Bering Strait migrated southward at the end of the last Ice Age.
The Chobot site includes a layer of dirt containing approximately 13,000-year-old Clovis points chiseled stone spear tips used to hunt woolly mammoths and other large Ice Age game that appear just below a thin, black mat of charred material. The authors of the U.S.-led PNAS paper believe the charred layer represents the fiery fallout of a massive extraterrestrial impact that abruptly ended the Clovis culture, kick started the extinction of mammoths, sabre-toothed cats and a host of other prehistoric creatures and wreaked havoc on global climate, initiating a 1,000-year cooling known as the Younger Dryas.
Chobot and each of the 17 other sites in North and South America, Europe and the Middle East that were examined by researchers for the PNAS study contains nanodiamonds or iron-rich spherules microscopic globular deposits often associated with an extinction-level cosmic collision.
Impact-related spherules have long been considered one of the most distinctive proxies in support of this hypothesis, the researchers state in the newly published paper. However, despite increasing evidence for (Younger Dryas Boundary) peaks in impact spherules, their presence and origin remain disputed.
But citing the February paper, the PNAS authors argue that their rival researchers neglected nine reliable studies showing significant YDB spherule abundances at about the same layer of approximately 13,000-year-old deposits.
We here present the results of one of the most comprehensive investigations of spherules ever undertaken to address questions of geochemical and morphological characteristics, distribution, origin, and processes involved in the formation of YDB spherules, the scientists state in the newly published paper.
This finding precludes all but a high-temperature cosmic impact event for the spherules, co-author James Kennett, a University of California Santa Barbara earth scientist, said in a summary of the PNAS study.
The climate changed rapidly and profoundly, added fellow co-author Kenneth Tankersley, an assistant professor of anthropology and geology at the University of Cincinnati. And coinciding with this very rapid global climate change (were) mass extinctions.
Two other co-authors of the PNAS study Lawrence Berkeley National Laboratory scientist Richard Firestone and private Arizona geoscientist Allen West recounted a visit to the Chobot site in their 2006 book The Cycle of Cosmic Catastrophes: How a Stone-Age Comet Changed the Course of World Culture.
They heaped praise in their book on the remarkable couple from Alberta.
For years, they have carried on a major amateur excavation of an important archeological site, without professional help and without outside funding, they wrote. While the outside world paid little attention, they have amassed a museum-quality collection of prehistoric artifacts.
May 27, 2013 23:24:13 #
Thank you for posting this most interesting story. Amazing what a couple of dedicated people can do with no funding but unlimited curiosity: thumbup: :thumbup:
May 28, 2013 10:39:54 #
Amazing what one discovers when one lets go of preconceived notions about how things are or were. It's too bad scientists are not prone to that anymore. Imagine how the world would be if Galileo had not challenged dogma. I think most scientists are just afraid for their jobs and standing within their disciplines.
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