Controls on andesitic glaciovolcanism at ice-capped volcanoes from field and experimental studies

Abstract Glaciovolcanic deposits at Tongariro and Ruapehu volcanoes, New Zealand, represent diverse styles of interaction between wet-based glaciers andesitic lava. There are iceconfined lavas, also hydroclastic breccia subaqueous pyroclastic that formed during effusive explosive eruptions into meltwater beneath the glacier; they rare among globally reported products glaciovolcanism. The apparent lack hydrovolcanically fragmented andesite ice-capped volcanoes has been attributed to a sites because either thermal characteristics limit production or drains out through leaky down steep volcano slopes. We used published field evidence novel, dynamic andesite-ice experiments show that, in some cases, accumulates under on rates increase as pushes against an ice wall. concur with models for sheets showing glacial conditions pre-eruption edifice morphology more important controls style glaciovolcanism its than magma composition properties magmas. can be useful proxies paleoenvironment, range hydrological environments which erupts greater hitherto appreciated.