A team of archaeologists led by James Kennett from the University of Oregon has discovered a widespread “black mat” layer in North American soil, which they believe is evidence of a catastrophic event that occurred approximately 12,800 years ago. This dark, organic-rich sediment layer, found at over 50 sites across North America, contains unusual markers such as nanodiamonds and iridium spikes, suggesting an extraterrestrial impact. This discovery challenges traditional views of gradual climate change and supports the Younger Dryas impact hypothesis, which posits a sudden extinction of megafauna and the collapse of the Clovis culture.
Discovery of the Black Mat Layer
The “black scar” or black mat was first observed in the 1950s in stratigraphic layers across North America, at sites such as Murray Springs, Arizona. This layer marks a sharp boundary between Paleoindian artifacts and post-event sediments. The black mat is characterized by a dark, charcoal-rich horizon that is 1-10 cm thick, containing high levels of organic carbon and fecal matter from extinct animals. Early reports from the 1990s by Allen West described it as “a thin, black, organic-rich layer”.
The geographic extent of the black mat is vast, covering at least 10,000 square kilometers from the Great Lakes to the Southwest. Consistent dating via radiocarbon places the formation of this layer between 12,900–11,700 years before present.
Evidence from Geochemical Anomalies
Further investigation into the black mat revealed the presence of nanodiamonds and microspherules, indicating high-temperature formation from an airburst event. These were discovered by Kennett’s team in 2009 at sites like Lake Cuitzeo in Mexico. Additionally, elevated levels of iridium, a platinum-group element rare on Earth but common in meteorites, were measured at 0.1-1 ppb in samples from Blackwater Draw, New Mexico, as reported in a 2011 paper by Firestone et al.
Shocked quartz grains showing planar deformation features were also found in concentrations up to 1% in the layer at Arlington Canyon, Santa Rosa Island, California. These features are linked to impact pressures over 5-10 GPa, further supporting the impact hypothesis.
Linking to the Younger Dryas Period
The temporal correlation of the black mat to the onset of the Younger Dryas cooling event around 12,800 years ago is striking. This period, marked by a 1,200-year temperature drop of up to 10°C in Greenland ice cores, coincides with the formation of the black mat. Environmental changes associated with this period include widespread wildfires, evidenced by soot and charcoal peaks in the sediment, covering 10% of Earth’s surface as estimated in a 2014 study by James et al.
The abrupt halt of the Clovis culture, with no dated sites post-12,800 years ago, is another significant correlation. Locations like the Gault site in Texas, where over 100,000 artifacts end precisely at the black mat boundary, further support this connection.
Impact Hypothesis and Comet Airburst Theory
The Comet Research Group, including Richard Firestone and Allen West, proposed a core theory that a fragmented comet exploded in the atmosphere over North America around 12,900 years ago. This theory, detailed in their 2007 PNAS paper, supports the evidence found in the black mat. Models supporting multiple airbursts rather than a single crater, with energy equivalent to 10-100 million Hiroshima bombs, were based on sediment distribution patterns analyzed in 2018 by Kennett et al. in the Journal of Geology.
Alternative explanations, such as volcanic activity, have been dismissed due to the lack of matching ash signatures. Kennett has stated, “The extraterrestrial markers are unequivocal.”
Implications for Megafauna Extinction
The black mat is also linked to the extinction of 35 genera of North American megafauna, including mammoths and saber-toothed cats. Approximately 80% of large mammal species disappeared within 300 years of the event. Evidence of biomass burning, with charcoal influx rates 100 times background levels, suggests habitat destruction across 50 million square kilometers, as quantified in a 2002 study by Firestone.
Human impacts were also significant, including dietary stress on Clovis hunters. Isotopic analysis of bones from sites like Rancholabre in Mexico shows a sharp drop in reliance on megafauna post-event.
Ongoing Research and Debates
Recent confirmations of the impact hypothesis include platinum anomalies in the Greenland GISP2 ice core at 12,800 years ago, matching black mat dates, reported in 2018 by Petaev et al. in the Proceedings of the National Academy of Sciences. However, skeptics like Mark Boslough have argued for natural wildfires in a 2012 Scientific American article. Rebuttals to these criticisms include replicated nanodiamond findings at 20 new sites.
Future work includes sediment coring in the Carolina Bays, over 500 elliptical depressions in the Southeast U.S. potentially formed by impact ejecta, as proposed by West in 2011. This ongoing research continues to shed light on this ancient apocalypse and its far-reaching effects on the history of our planet.
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