Postglacial volcanism in Iceland

Iceland is one of the most active and productive terrestrial volcanic regions, with eruption frequency of ≥20 events per century and magma output rates of ≥5 km 3 per century.Although Iceland is dominated by mac magmatism and volcanism, as is evident from 91:6:3 distribution of mac, intermediate and silicic eruptions, its record also features most common terrestrial magma types and eruption styles.Postglacial volcanism is conned to the neovolcanic zones where 30 active volcanic systems are responsible for most of the Holocene activity.On the basis of our current post-glacial eruption data set we estimate that Icelandic volcanism has produced around 2400 eruptions and about 566±100 km 3 of erupted magma in the last 11 ka.Effusive activity accounts for ∼500 eruptions; the remainder is explosive and dictated by subglacial mac events (∼77%), demonstrating strong environmental inuence on eruption styles in Iceland.In terms of magma output the record is dominated by large volume (>1 km 3 ) effusive mac eruptions.About 50 such eruptions have occurred throughout postglacial time or ∼2% of the total number of eruptions.However, collectively these events produced about 55% of the postglacial magma volume.The Eastern Volcanic Zone is responsible for >80% of the eruptions and ∼60% of the erupted magma volume and has been by far the most prolic producer among the neovolcanic zones.Furthermore, the volume of mac effusive eruptions is not evenly distributed through post-glacial time, because only 30% (∼111 km 3 ) of the total volume was produced in the last 5 ka and the remaining 70% ( 258 km 3 ) between 5-11 ka.However, the production rate per millennia within these two periods appears to be fairly even, ranging from 20-30 km 3 in <5 ka period and 35-40 km 3 in the 5-10 ka interval.The exception is the 10-11 ka interval, when ∼70 km 3 of mac lava was formed by the effusive activity or close to double the volume produced per millennia in the period that followed.