New evidence of ancient Santorini eruption proves archaeologists right

The exact dating of the famous volcanic explosion has been dividing scientists for decades with estimates varying between 3,500 to 3,600 years. The new data comes to shore up traditional archaeological data that had gone against carbon 14 dating conducted in the 1980s. Those studies had shown a possible explosion between 1642 and 1628 give or take a few years.
The last such study from Denmark conducted on pieces of olive wood, found under ash, proposed such dates, however, an international team of researchers led by Paolo Cherubini from the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) has demonstrated in the scientific journal Antiquity that this method cannot provide reliable results. The scientists show that cardon 14 dating of individual pieces of olive wood enveloped by volcanic ash is too unreliable for precise dating.

“Investigating such wood samples only makes sense if it can be clearly shown that the trees were still alive at the time of the eruption. In the case of old olive trees in the Mediterranean region, it is not at all unusual for dead branches to stay in place for several decades”, says Paolo Cherubini. If  carbon 14 dating is carried out, it must use an international reference curve, which in the case of the period of the volcanic eruption is based on tree-ring measurements from trees that are more than 4,000 years old.
Paolo Cherubini has investigated wood from many olive trees in southern Europe and point out the limitations of tree-ring dating: "In warm regions like Santorini, with frequent dry periods in the summer and spring-like winters, olive wood often only produces tree rings that are difficult to identify. Instead, wood-density fluctuations are found inside certain rings." These arise mainly in dry periods of the year. It is easy for even an expert to confuse such density fluctuations with actual annual tree rings. Consequently, a piece of olive wood dated as being 72 years old could instead be just 30 years old.
By way of a 'blind test’' Cherubini recently asked 10 experts in five tree-ring laboratories in various countries to date the same wood samples from olive-tree branches. These came from trees growing today on Santorini. As expected, this produced sobering results: the number of tree rings found varied between laboratories by more than 44%. This unreliability alone makes precisely dating a piece of wood from the period of the eruption seem unrealistic. Furthermore, the same amount of carbon isotope (14C) in a given sample can quite easily result in different dating results when comparing it with the reference curve, whereas only precisely dated tree rings would allow the age of the tree to be correctly determined. This leads Cherubini and his team of authors to conclude that using 14C dating to calculate the age of an olive wood branch has to be taken with caution.

According to Cherubini, the uncertainties mentioned above can easily give rise to differences of several decades in the dating of Santorini's eruption. Therefore he believes that the hypothesis that Santorini's volcano erupted almost a century earlier cannot be confirmed using current methods. In his opinion, answers are more likely to be found through interdisciplinary research involving close cooperation between archaeologists, climatologists, geoscientists, dendroclimatologists and historians, allowing a general view of the situation to emerge.
The findings come to prop up traditional archaeological dating. Archaeologists have traditionally placed the explosion at approximately 1500 BC but radiocarbon dates, including analysis of an olive tree buried beneath a lava flow from the volcano which gave a date between 1627 BCE and 1600 BCE with a 95% confidence interval, had suggested a date over a century earlier.  The radiocarbon dates, which were in disagreement with archaeological dates, have significant implications for the accepted chronology of Eastern Mediterranean cultures. The Minoan eruption is a key marker for the Bronze Age archaeology of the Eastern Mediterranean world. It provides a fixed point for aligning the entire chronology of the second millennium BC in the Aegean, because evidence of the eruption is found throughout the region. Despite this evidence, the exact date of the eruption has been difficult to determine.
In 2012 one of the proponents of a late date, Felix Höflmayer, argued that archaeological evidence could be consistent with a date as early as 1570 BCE, reducing the discrepancy to around fifty years, and in 2013 archaeologist Kevin Walsh, accepting the radiocarbon dating, suggested a possible date of 1628.

Archaeologists developed the Late Bronze Age chronologies of eastern Mediterranean cultures by analyzing the origin of artifacts (for example, items from Crete, mainland Greece, Cyprus or Canaan) found in each archaeological layer. If an artifact's origin can be accurately dated, then it gives a reference date for the layer in which it is found. If the Santorini eruption could be associated with a given layer of Cretan (or other) culture, chronologists could use the date of that layer to date the eruption itself. Since Thera's culture at the time of destruction was similar to the Late Minoan IA (LMIA) culture on Crete, LMIA is the baseline to establish chronology elsewhere. The eruption also aligns with Late Cycladic I (LCI) and Late Helladic I (LHI) cultures, but predates Peloponnesian LHI. Archeological digs on Akrotiri have also yielded fragments of nine Syro-Palestinian Middle Bronze II (MBII) gypsum vessels.
The Aegean prehistorians felt so confident about their calculations that they rejected early radiocarbon dates in the 1970s for LMI/LCI Thera, because radiocarbon suggested a date about a century earlier than the "traditional" dates.