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Tree Ring Clocks

August 25, 2016

Spikes in radiation caused by historic solar flares could help archaeologists precisely date ancient events.


Mike Dee at Oxford Radiocarbon Lab D. Chivall

Michael Dee in the Oxford Radiocarbon Lab (D. Chivall)


Tree ring clocks. I’m Bob Hirshon and this is Science Update.

Pinning down the precise year an ancient historical event took place is often difficult. Now, University of Oxford researchers think massive solar storms in ancient times could help archaeologists narrow down the timing. Chemist Michael Dee says in the year 775 AD, for example, solar flares created a spike of radioactive carbon dioxide in the atmosphere. That carbon was incorporated into all plants growing at the time. He and Benjamin Pope report in the Proceedings of the Royal Society A that tree rings in timber from ancient Maya temples coupled with calendar inscriptions could allow archaeologists to precisely date the temples relative to 775AD.

MICHAEL DEE (University of Oxford):

We’ll know when the beam will be cut down, and that will have to be very very close to when the monument was built.


The technique could pinpoint dates from ancient Egypt as well. I’m Bob Hirshon, for AAAS, the science society.

Story by Susanne Bard