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Credit: D. Breger, LDEO; sample courtesy of G. Jacoby.
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Mongolian Frost Rings
Dee Breger
Using a scanning electron microscope, Dee Breger of the SEM and X-Ray Microanalysis Facility at Columbia University's Lamont-Doherty Earth Observatory, Palisades, New York, captured this image of tree rings from a tiny fragment of an ancient Siberian pine tree -- a fragment that offers a snapshot from Earth's recent history. The narrow, deformed rings at the center of the image correspond to the years 536 to 537 A.D. -- and graphically record a catastrophic summer cooling that froze the tree's sap, and that may have been linked to a massive eruption of a young volcano, the precursor to Krakatoa.
See a larger version of the image
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