The Younger Dryas period, also sometimes commonly called “The Big Freeze,” was a 1,300-year-long interval of time (from 12,800 to 11,500 years ago) in which conditions were cold enough that many animals such as saber-toothed cats and mammoths began extinct in North America
In fact, the researchers found that the layer where the diamonds were found included a “black mat” of “carbon-rich material” that separated the bones of animals and artifacts from the Clovis Indians found before that time-period but not after it.
Kennett explains, "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.” [Reuters]
The researchers state that the six sites in North America could have experienced one giant explosion or multiple smaller ones, which could have likely caused giant fires and extreme pressures.
Dr. Kennett explains, “These data support the hypothesis that a swarm of comets or carbonaceous chondrites (a type of meteorite) produced multiple air shocks and possible surface impacts at 12,900 (years ago).” [Reuters]
The Reuters article went on to explain, “The heat and pressure could have melted part of the Greenland ice sheet, causing currents to change and affecting climate. Any impacts would have kicked up dust that would have shrouded the sun and lowered temperatures, endangering plants and animals.”
Kennett concluded, "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."