Abstract
Meteoroid bombardment of the Earth-Moon system must have caused catastrophic damage to the terrestrial ecosphere. However, ancient meteoroid impacts and their relations to environmental changes are not well understood because of erosion and/or resurfacing processes on Earth. Here, we investigate the formation ages of 59 lunar craters with fresh morphologies and diameters greater than approximately 20 km and first find that 8 of 59 craters were formed simultaneously. Considering the radiometric ages of ejecta from Copernicus crater and impact glass spherules from various Apollo landing sites, we conclude that sporadic meteoroid bombardment occurred across the whole Moon at approximately 800 Ma. Based on crater scaling laws and collision probabilities with the Earth and Moon, we suggest that at least (4–5) × 1016 kg of meteoroids, approximately 30–60 times more than the Chicxulub impact, must have plunged into the Earth-Moon system immediately before the Cryogenian, which was an era of great environmental changes.
Highlights
Meteoroid bombardment of the Earth-Moon system must have caused catastrophic damage to the terrestrial ecosphere
After the first discovery of fossil L-chondrites in Ordovician limestones in Sweden[5], abundant L-chondrites, meteorite-tracing chromite grains and iridium enrichment have been found in Sweden, England, Scotland, China, and Russia in rocks whose stratigraphic ages are 470 ~ 480 million years (Ma)[6,7]
The results show that the possibility that seven of the 59 craters formed at the same time by chance is 0.69%, where the 54S161E crater (747 ± 92 Ma) is masked because it is an obvious outlier with large uncertainties
Summary
Meteoroid bombardment of the Earth-Moon system must have caused catastrophic damage to the terrestrial ecosphere.
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