What can tree rings tell us about Earth’s past?

This month, scientists from University of Oxford published extra-ordinary finding. They have identified a new way of putting accurate dates to great events of prehistory. This new way is called astrochronology and, in this case, it uses tree rings. 

It looks that rare and spectacular solar storms have left their traces in trees over the past five thousands years. Every tree growing at the time of such a sun storm, anywhere in the world, would have preserved a record of it.

This is opening completely new possibilities for high-precision chronometry (science of the measurement of time), and chronology (science of locating events in time).

So far, scientists were using carbon dating by comparing the ration between two isotopes of the element carbon, C-14 and C-12, present in old samples of organic material. Nevertheless, this technique often leads to quite big errors, sometimes between 50-100 years.

However, by combining carbon dating with violent solar storms that occurred in the past, may enable scientists to date material much more precise.

In a new paper, the authors explain how harvesting such data could revolutionize the study of ancient civilizations such as the Egyptian and Mayan worlds.

Lead author Dr Michael Dee, from the School of Archaeology at the University of Oxford, said:

“Such markers can be easily identified in known-age tree-rings and are fixed in time. In the past, we have had floating estimates of when things may have happened, but these secret clocks could reset chronologies concerning important world civilizations with the potential to date events that happened many thousands of years ago to the exact year.”

DSC05067Tree rings of Douglas fir (Pseudotsuga menziesii) in Black Forest (Schwarzwald) in Germany. Photo: Rafal Chudy.  

Whole article you can find here: Dee M.W., Pope B.J.S. 2016. Anchoring historical sequences using a new source of astro-chronological tie-points. Proceedings of the Royal Society. A mathematical, physical and engineering sciences. Volume 472, issue 2192.

Image source: NASA

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