Splatters of Molten Rock Signal Period of Intense Asteroid Impacts On Earth
New research reveals that the Archean era -- a formative time for early life from 3.8 billion years ago to 2.5 billion years ago -- experienced far more major asteroid impacts than had been previously thought, with a few impacts perhaps even rivaling those that produced the largest craters on the Moon, according to a paper recently published online in Nature.
This image shows an artistís depiction of a 10-kilometer (six-mile) diameter asteroid striking the Earth. Approximately 70 of these dinosaur killer-sized or larger impacts hit the Earth over a span that lasted between 3.8 and 1.8 billion years ago. They are capable of producing a global millimeter- to centimeter-thick rock layer that contains impact debris: sand-sized droplets, or spherules, of molten rock that rained down from the huge molten plumes made by the mega-impact. (Credit: Art by Don Davis)