More Evidence To Support The Younger Dryas Impact Hypothesis

Back in August, Discovery Magazine published an article entitled "A Comet Could’ve Caused Rapid Climate Shift Around 12,800 Years Ago," which provides a summary of the theory that an impact event caused the Younger Dryas--a rapid cooling of the planet approximately 12,000 years ago just as the Earth had been warming from the preceding ice age. Established scientists have fought this theory tooth and nail since it was first proposed in the early 2000s, but the evidence supporting it continues to build while the arguments against it continue to fall. An excerpt:

    Dropping around 10 degrees Celsius in the span of a single year, then stabilizing at a lower level for around 1,200 years, the temperatures of the Northern Hemisphere were abnormally cold throughout the course of the Younger Dryas, potentially prompting consequences for the plants, animals, and human civilizations that lived there. But whatever the consequences, their cause is typically attributed to an increase in glacial meltwater, which would have weakened the ocean currents that transport warm water throughout the Northern Hemisphere.

    While some scientists suspect that this glacial meltwater arose without a comet, others say that one of these celestial ice clumps created the melt. Indeed, the proponents of the “Younger Dryas Impact Hypothesis” posit that the debris from a disintegrating comet destabilized Earth’s ice sheet, causing the increase in glacial meltwater that disrupted the ocean’s circulation.

    The hypothesis has found some support in terrestrial sediment and ice cores, though it has lacked evidence from deep-sea ones. Hoping to gather this evidence, the authors of the new study investigated the geochemistry of four deep-sea sediment cores from the time of the Younger Dryas event, taken from the floor of Baffin Bay.

    Using an assortment of microscopy and spectroscopy techniques, which offered a closer look at the cores and their chemical compositions, the researchers concluded that the sediments contained material from a comet, based on “the morphology and composition of the microparticles found,” Tselmovich said in the release.

    “The amount of comet dust in the atmosphere was enough to cause a short-term ‘impact winter,’ followed by a 1,400-year cooling period,” he added in the release. “The results obtained confirm the hypothesis that the Earth collided with a large comet about 12,800 years ago.”