Moles, J.D., McGarvie, D., Stevenson, J.A., Sherlock, S.C., Abbott, P.M., Jenner, F.E. & Halton, A..M. (2019) InPress, Geology. Widespread tephra dispersal and ignimbrite emplacement from a subglacial volcano (Torfajökull, Iceland)
Using geochemistry and geochronology, this paper correlates a regionally important Pleistocene tephra horizon – the rhyolitic component of North Atlantic Ash Zone II (II-RHY-1) – and the Thórsmörk Ignimbrite with rhyolitic tuyas at Torfajökull volcano, Iceland. The widely dispersed products of this eruption represent a valuable tie-line between terrestrial, marine and ice core paleoenvironmental records. Using the tephra horizon, estimates of ice thickness and extent derived from the eruption deposits can be directly linked to the regional climate archive, which records the eruption at the onset of Greenland Stadial 15.2.
In this paper we use correlation methods to a) assess the tephra dispersal mechanisms of rhyolitic glaciovolcanic eruptions, and b) precisely integrate glaciovolcanism-derived paleoenvironmental data with the regional climate record.
The research involved Ar-Ar dating of the Thórsmörk Ignimbrite which resulted in an age of 51.3 ± 4.2 ka and resolves the long-standing ambiguity regarding the origin of II-RHY-1 and the Thórsmörk Ignimbrite by recognizing Torfajökull, not Tindfjallajökull, as the source volcano.