Scientists discovered shocked quartz at three Clovis-era archaeological sites in the southwestern United States, strengthening evidence that a fragmented comet exploded in Earth's atmosphere nearly 13,000 years ago and may have triggered the extinction of mammoths, mastodons, and other Ice Age megafauna.
The comet airburst, occurring at the onset of the Younger Dryas period around 12,800 years ago, likely ignited widespread fires that filled the atmosphere with debris, blocked sunlight, and produced an "impact winter" that contributed to rapid climate cooling and the collapse of the Clovis culture.
Researchers have gathered multiple lines of evidence over two decades, including a carbon-rich "black mat" sediment layer indicating extensive burning, elevated platinum and iridium levels, nanodiamonds, and metallic spherules, all supporting a cosmic impact despite the absence of a crater.
Source: sciencedaily
