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All Images

Comet May Have Exploded Over North America 13,000 Years Ago

Back to article | Note about images

Photo of rock with arrow pointing to "black mat" of algal growth

A "black mat" of algal growth in Arizona marks a line of extinction at 12,900 years ago; Clovis points and mammoth skeletons were found at the line but not above it.

Credit: Allen West, UCSB

Download the high-resolution JPG version of the image. (2.6 MB)

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