Detection of the historical Askja ad 1875 and modern Icelandic cryptotephras in varved lake sediments – results from a first systematic search in northern Poland

Abstract

Volcanic ash can disperse thousands of kilometres from the source volcano and provide valuable chronostratigraphic markers for palaeoclimate studies. We present new cryptotephra findings of historical and modern Icelandic eruptions in annually laminated lacustrine sediment records from several sites within a 570 km SW-NE transect across northern Poland. Sediments from the two lakes Wąsoskie and Szurpiły contain glass shards originating from the Plinian Askja AD 1875 eruption and showing bimodal, rhyolitic and dacitic affinities. A further cryptotephra finding in Lake Lubińskie suggests a potential origin from the Hekla AD 1845 eruption. These new findings extend the tephra dispersal map towards the southeast and provide valuable isochrons for the synchronisation of palaeoclimate proxy data at the termination of the Little Ice Age in central eastern Europe. Very low glass concentrations of modern cryptotephra in Lake Wąsoskie were potentially correlated with the Eyjafjallajökull AD 2010 eruption. Further findings in the uppermost sediments of lakes Szurpiły and Żabińskie in northeastern Poland tentatively suggest other sources from either the Hekla and/or Kamchatkan volcanoes.