Raw major element oxide data obtained by EPMA for volcanic events analysed from two proximal sites from Iceland between 750 and 940 CE

Raw major element oxide data for volcanic events analysed from two proximal sites from Iceland across the period 750-940 CE. Tephra (ash) samples were taken from soil outcrops in Iceland [Atley, 63.67295°N/18.68231°W; Quarry Hafid, 64.054°N/19.786°W] for candidate events and this material was analysed using electron probe micro-analysis (EPMA) at the University of Bern, Switzerland. The location of the outcrop, sample depth, raw oxide values, and correlating horizon are provided.