Pressures of Crystallization of Icelandic Magmas

• Main Authors: Daniel F. Kelley, Michael Barton
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2007
• Subjects: Askja; Katla; Krafla; Mid-Atlantic Ridge; Ice Sheet; Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.495.29; http://petrology.oxfordjournals.org/content/49/3/465.full.pdf

Iceland lies astride the Mid-Atlantic Ridge and was created by sea-floor spreading that began about 55Ma.The crust is anomalously thick (20^40 km), indicating higher melt productivity in the underlying mantle compared with normal ridge segments as a result of the presence of a mantle plume or upwelling centered beneath the northwestern edge of the Vatnajo « kull ice sheet. Seismic and volcanic activity is concentrated in 50 km wide neovolcanic or rift zones, which mark the subaerial Mid-Atlantic Ridge, and in three flank zones. Geodetic and geophysical studies provide evidence for magma chambers located over a range of depths (15^21km) in the crust, with shallow magma chambers beneath some volcanic centers (Katla, Grimsvo « tn, Eyjafjallajo « kull), and both shallow and deep chambers beneath others (e.g. Krafla and Askja).We have compiled analyses of basalt glass with geochemical characteristics indicating crystallization of ol^plag^cpx from 28 volcanic centers in the