Volcanic ash dating
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The Codola Tephra from Vesuvius, the Nisyros Island Tephra (Upper Member), and the Pantelleria Green Tuff are all found as far-traveled tephra layers and occurred within ±20 ka of the CI eruption.
Representative 2σ uncertainty ranges are shown ( The CI eruption occurred during the last glacial cycle, just after the onset of a millennial-scale cold stadial that encompassed HE4, a northern hemisphere-wide climatic event of extreme cold and aridity (22).
These hypotheses are difficult to test, however, because of chronological uncertainties that blur the precise timing of archaeological and geologic events (6).
Whereas climate was capable of major swings within a human lifespan (3), it is seldom possible to link cultural and environmental responses to such abrupt shifts with similar chronological precision because of common sedimentary complications in archaeological and geologic sequences (13) and dating uncertainties that, for the period under consideration, are typically centennial to millennial in scale (14).
Focusing only on visible volcanic ash layers, however, limits the number of isochrons that can be used as well as the geographic range over which they can be traced.