Nanodiamonds in the Younger Dryas Boundary Sediment Layer

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 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.

Instead he found MILES OF MUCK filled with the remains of mammoth, mastodon, several kinds of bison, horses, wolves, bears, and lions. Just north of Fairbanks, Hibbens and his associates watched as bulldozers pushed the half-melted muck into sluice boxes for the extraction of gold.

Animal tusks and bones rolled up in front of the blades "like shavings before a giant plane." The carcasses were found in all attitudes of death, most of them "pulled apart by the same unexplainable prehistoric catastrophic disturbance." (Hibben, 1946)

The evidence of the violence of nature combined with the stench of rotting carcasses was staggering. The ice fields containing these remains stretched for hundred of miles in every direction. (Hibben, 1946) Trees and animals, layers of peat and mosses, twisted and mangled together like some giant mixer had jumbled them some 10,000 years ago, and then froze them into a solid mass.