2017 March 15 - April 24
2017 May 17 - June 29
2017 BTR deadline: 04/17/17
2017 October 11 - December 21
2017 Proposal deadline: 08/01/17
2017 BTR deadline: 09/10/17
X-rays Track Tree-Ring Growth Anomalies
Experts Charlotte Pearson and Sturt Manning, from the Cornell Tree-Ring Laboratory, worked with CHESS staff using x-ray fluorescence to record the chemical composition of individual tree-rings for historical data. Samples of Juniper wood were borrowed from the Aegean Dendrochronology Project archives to study the growth anomalies seen at relative ring 854. X-ray maps of sulfur and zinc concentrations provide direct evidence, for the first time, that the growth anomaly might be caused by volcanic activities attributed to the Minoan eruption of Thera mid-late 17th century BC. The timing of this eruption is important because it is believed to be a key event leading to the rise of ancient Greece.
This study found that, for years 1650 BC and 1628 BC, the only replicable indication of major elemental change was found at relative ring 854. If it could be demonstrated that this elemental change is unique over several hundred years, this would provide further evidence to improve the credibility of the proposed historical links with the largest volcanic eruption in the region at the time. This work showed that non-invasive x-ray fluorescence analysis can provide unique and useful spatially-resolved historical data to add to the portfolio of other chemically-sensitive techniques.
For more information see the Cornell Tree-Ring Laboratory web site: http://dendro.cornell.edu/
See two recent publications:
Pearson, C. L., Dale, D. S., Brewer, P. W., Salzer, M. W., Lipton, J. & Manning, S. W. (2009) Dendrochemistry of White Mountain Bristlecone pines - an investigation via Synchrotron Radiation Scanning X-Ray Fluorescence Microscopy. Journal of Geophysical Research 114: G01023.
Pearson, C. L., Dale, D. S., Brewer, P. W., Kuniholm, P. I., Lipton, J. & Manning, S. W. (2009) Dendrochemical analysis of a tree-ring growth anomaly associated with the Late Bronze Age eruption of Thera. Journal of Archaeological Science 36: 1206-1214
[Figures "3" and "6" below from article in "Journal of Archaeological Science 36 (2009)."]
submitted by: E. Fontes