Iceland is on high alert after seismologists detected an increase in volcanic activity at the Bardarbunga Volcano.
Volcanic eruptions may release ‘Tephra‘; tiny shards of volcanic rock which carry a geochemical ‘fingerprint’ unique to a specific eruption. Tephra are carried through the atmosphere before being deposited as fine layers in soils and sediments.
Geologists use tephra layers, combined with knowledge of the timing of the eruption that produced them, as a time marker to determine the age of soils and other materials (e.g. fossil pollen).