Tree rings helped determine the date of the eruption of the volcano Thira in Greece. A study by scientists from the University of Arizona confirms the hypothesis that the eruption occurred around 1560 BC. The work was published in the journal Proceedings of the National Academy of Sciences.
Trees grow in accordance with the conditions of their environment and, depending on them, annually a new layer of concentric growth called the tree ring. An analysis of this layer allows one to obtain data on precipitation, temperature, forest fires, soil conditions, and many other factors in the year in which it was formed. Trees can even record solar activity as it rises and falls.
When sequences of rings of trees of different ages overlap and stack together, they can tell the story of events that took place over hundreds and thousands of years – and give scientists an idea of past climatic conditions.
“The longest chronology in the world is 12 thousand years old. But in the Mediterranean the problem is that we do not have a complete, continuous record dating back to the time of the eruption of Tyra. We have studied well over the past 2000 years, but there is a gap. We have tree rings, but we don’t know exactly what dates they correspond to. This is called a floating timeline”.
Charlotte Pearson, lead author of the study
Filling this gap would determine the exact date of the volcanic eruption on the island of Thira (Santorini), which destroyed the ancient Minoan civilization. The date of this event, which is one of the largest in the history of mankind, has still not been precisely established.
The researchers proposed a new technique for analyzing the age of the rings: they used carbon-14 samples that were stored in tree rings to link the chronology to similar and already dated samples from other tree ring sequences.
Researchers then analyzed tree ring samples using X-ray fluorescence scanning. An analysis of the entire period of time when the eruption of Tyra could occur showed that approximately 1560 BC in the samples, the calcium content dropped sharply. This confirms the hypothesis that the eruption occurred at this time.