Pressures of Crystallization of Icelandic Magmas
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 upwell...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
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2007
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| 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 |
| Summary: | 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 |
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