Ancient Spores May Disprove Comet Cataclysm

The presence of tiny balls of fungus and feces in materials dating over several millennia may disprove the theory that an exploding comet 12,900 years ago ignited a dramatic drop in earth temperature called the Younger Dryas.

The Younger Dryas has been associated with the extinction of mammoths and other Ice Age mammals in North America. But the theory that a comet or asteroid explosion is behind the cooling event is wrong, according to study leader Andrew C. Scott, a paleobotanist at Royal Holloway University in London.

According to National Geographic:

For years proponents of the impact theory have cited tiny spherules of carbon found in a layer of charred sediment throughout North America that dates to the Younger Dryas period. According to the theory, these spherules are organic matter subjected to intense heat after debris from an exploded meteor rained down on Earth, sparking massive wildfires. 

The new research, however, detected carbon spherules in soil layers from before, during, and after the Younger Dryas, making it hard to argue that the particles are products of a sudden impact.

"All these particles are of natural biological origin and are not related to either intense wildfires or cosmic impacts," Scott said in an email. "The press and public are very interested in catastrophic explanations. But it is important that when evidence stacks up to show the theory does not work, then it should be abandoned."

Scott said fungal spores have similar microscopic features to nanodiamonds, which some researchers have cited as evidence of a massive comet explosion above the earth’s surface nearly 13,000 years ago.

Click here for the complete National Geographic article.
Click here for earlier post on nanodiamond theory.

Diamond Dust Points to Comet Cataclysm

Diamond dust dating to 12,900 years ago exists at six North American sites, pointing to Earth's impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites, reports a nine-member scientific team.

Nanodiamonds ~ produced under high-temperature, high-pressure conditions created by cosmic impacts and have been found in meteorites ~ are concentrated in similarly aged sediments at sites in Arizona, Oklahoma, Michigan, South Carolina and at two additional sites in Canada.

According to ScienceDaily, last year a team of scientists proposed that a cosmic impact event ~ possibly multiple airbursts of comets ~ set off a 1,300-year-long cold spell known as the Younger Dryas and led to the extinction of a large range of animals, including mammoths, across North America.

Now, reporting in today’s issue of the journal Science, a team led by the University of Oregon's Douglas J. Kennett, a member of the original research team, report finding billions of nanometer-sized diamonds concentrated in sediments ~ weighing from about 10 to 2,700 parts per billion ~ in the six locations during digs funded by the National Science Foundation.

"The nanodiamonds that we found at all six locations exist only in sediments associated with the Younger Dryas Boundary layers, not above it or below it," Kennett, a UO archaeologist, told ScienceDaily. "These discoveries provide strong evidence for a cosmic impact event at approximately 12,900 years ago that would have had enormous environmental consequences for plants, animals and humans across North America."

Click here for the complete ScienceDaily article.

Click here for today's Washington Post article.

This post originally appeared on my Ancient Tides blog.