All of this happened about 12,900 years ago: so this might not be the most gripping post in this blog for you. On the other hand, if you're as interested as I am, in what was happening to a bunch of mammoths, little flowers, and people back then, keep reading.
- "Study: Diamonds link comet to mammal extinction"
CNN (January 2, 2009)- "(CNN) -- Tiny diamonds found in the soil are "strong evidence" a comet exploded on or above North America nearly 13,000 years ago, leading to the extinction of dozens of mammal species, according to a study...."
- "Diamonds suggest comets caused killer cold spell"
Reuters (January 2, 2009)- "WASHINGTON (Reuters) - Tiny diamonds sprinkled across North America suggest a "swarm" of comets hit the Earth around 13,000 years ago, kicking up enough disruption to send the planet into a cold spell and drive mammoths and other creatures into extinction, scientists reported on Friday...."
- " 'Giant comet strike' on America caused extinction of ancient civilisation"
TimesOnline (January 2, 2009)- "An entire civilisation that suddenly vanished off the face of the earth 12,900 years ago — along with several species of prehistoric animals — may have been made extinct because of a devastating comet strike...."
- "Nanodiamonds in the Younger Dryas Boundary Sediment Layer"
Science (January 2, 2009)- "We report abundant nanodiamonds in sediments dating to 12.9 ± 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth's typical surficial processes but common to cosmic impacts. N-diamond concentrations range from {asymp}10 to 3700 parts per billion by weight, comparable to amounts found in known impact layers. These diamonds provide strong evidence for Earth's collision with a rare swarm of carbonaceous chondrites or comets at the onset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with severe repercussions for plants, animals, and humans in North America...."
- "Six North American sites hold 12,900-year-old nanodiamond-rich soil"
University of Oregon Media Relations (January 2, 2009)- "Discoveries consistent with theory of Clovis-age disruption by cosmic event, say nine-member team led by the UO's Doug Kennett
- "EUGENE, Ore. -- (Jan. 2, 2009) -- Abundant tiny particles of diamond dust exist in sediments dating to 12,900 years ago at six North American sites, adding strong evidence for Earth’s impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites, reports a nine-member scientific team...."
However, between tiny carbon crystals (or nanodiamonds - a much cooler term), a dark mat of carbon-rich stuff over the last Clovis artifacts, and other evidence, it looks quite likely that something hit Earth over North America about 12,900 years ago. Whether it was a lot of carbon-rich space rocks, or a swarm of comets, it was very bad news for the Clovis people, and the plants and animals the gathered and hunted. Humans bounced back, eventually, but mammoths and some other creatures didn't.
More about the Younger Dryas:
- "Abrupt Climate Change - The Younger Dryas"
The Earth Institute at Columbia Univeristy - "The Younger Dryas Period"
Part of "Climate of the Last 20,000 Years"
Group 18, Department of Atmospheric Services, University of Washington - "3000 BC: Notes and References"
Stanford University
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