Detection of the Askja AD 1875 cryptotephra in Latvia, Eastern Europe

We report the first geochemically confirmed findings of the Askja volcano (Iceland) AD 1875 eruption cryptotephra in Eastern Europe. The cryptotephra finding in Latvia is the easternmost finding of the Askja AD 1875 so far, providing an important time marker in the sediments. Although low concentrations of Askja AD 1875 rhyolitic glass shards were recorded, our findings suggest the possibility of also tracing other historical cryptotephras in lacustrine and peat sediments in Eastern Europe. We use the Askja AD 1875 tephra isochrone to synchronize pollen data of human activities, i.e. rye (Secale cereale) cultivation. Our comparison of Secale pollen from two sites reveals that there were minor dissimilarities in the timing of highest rye cultivation, and that a synchronous decrease of rye cultivation occurred at both sites few years after the Askja eruption at AD 1875.