Rapid assembly and eruption of a shallow silicic magma reservoir, Reyðarártindur Pluton, Southeast Iceland.

Although it is widely accepted that shallow silicic magma reservoirs exist, and can feed eruptions, their dynamics longevity are a topic of debate. Here, we use field mapping, geochemistry, 3D pluton reconstruction thermal model to investigate the assembly eruptive history Reyðarártindur Pluton, southeast Iceland. Primarily, exposed constructed single rock unit, Main Granite (69.9–77.7 wt.% SiO2). Two further units locally as enclaves at base exposure, Enclaves (67.4–70.2 SiO2), Quartz Monzonite (61.8–67.3 Geochemically, related were likely derived from same source reservoir. In 3D, has shape characterized by flat roof segments vertically offset volume >2.5 km3. The intruded dikes pluton, in two locations displays depressions associated with large dikes. Within these particular partially wholly tuffisitic, compositions range quartz monzonite granite. We interpret zones eruption-feeding conduits pluton. A lack cooling contacts throughout indicates rapid emplacement calculates top 75 m would have rheologically locked up within 1,000 years. Hence, argue Pluton was an ephemeral part wider plumbing system feeds volcano, timeframes eruption rapid.