What kicked off the Earths rapid cooling 12,800 years ago?
Layers of ice in Greenland show that this cool period in the Northern Hemisphere lasted about 1,400 years.
This freshwater influxshut down ocean circulationand ended up cooling the climate.
40% off TNW Conference!
The evidence is mounting that the cause of the Younger Dryas cooling climate came from outer space.
A collision from space would leave its mark on Earth.
Vadim Sadovski/Shutterstock.com
What would an Earth impact leave behind?
As much as 10 percent of global forests and grasslands may have burned at this time.
Looking for more clues, researchers have pored through the widely distributedYounger Dryas Boundarystratigraphic layer.
While many studies have provided evidence supporting the Younger Dryas impact,othershave failed to replicate evidence.
White Pond has been part of this landscape for 20,000 years or more.
Instead, geologists and archaeologists like me can look to natural lakes.
They accumulate sediments over time, preserving layer by layer a record of past climate and environmental conditions.
White Pond is one such natural lake, situated in southern Kershaw County, South Carolina.
It covers nearly 26 hectares and is generally shallow, less than 2 meters even at its deepest portions.
Collecting sediment cores from White Pond in 2016.
The long sediment cores are cut in half so that extract samples for analysis.
That is where we concentrated our hunt for evidence of an extraterrestrial impact.
We were particularly looking for platinum.
Most recently, the Younger Dryas platinum anomaly has been found inSouth Africa.
The sediments also had an unusual ratio of platinum to palladium.
Both of these rare earth elements occur naturally in very small quantities.
My team also found a large increase in soot, indicative of large-scale regional wildfires.
Photomicrograph of Sporormiella fungal spores associated with the dung of megaherbivores from White Pond.
