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| Titel |
Effects of present day deglaciation in Iceland on the mantle melt production rate |
| VerfasserIn |
Peter Schmidt, Björn Lund, Christoph Hieronymus, John Maclennan, Thóra Árnadóttir, Carolina Pagli |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081061
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| Zusammenfassung |
| The ongoing deglaciation in Iceland not only causes uplift at the surface but also
decompression of the mantle below, leading to increased magma production. Here we study
glacially induced decompressional melting using 3D models of glacial isostatic adjustment in
Iceland since 1890. We find that the mean glacially induced pressure rate of change in the
mantle increases the melt production rate by 100-140%, or an additional 0.21-0.23 km3 of
magma per year across Iceland. The greatest volumetric increase is found directly beneath the
largest ice cap Vatnajökull, co-located with the most productive Icelandic volcanoes, where
approximately 20% of the melt associated with glacial unloading is generated. If, in
addition, melts are being channeled from the flanks of the melting region towards
the central rift, up to 50% of the additional magma might reach the base of the
elastic lithosphere beneath or close to the Vatnajökull ice cap, equivalent to more
than half of the magma volume extruded during the 2010 Eyjafjallajökull summit
eruption per year. Our results are significantly larger than previous estimates which
considered only the effect of deglaciation of Vatnajökull and mantle melting directly
beneath. Although the ongoing deglaciation in Iceland significantly increases the melt
production rate in the mantle, the increase in melt supply rate (MSR) at the base of the
lithosphere is delayed. If the melt ascent velocity is lower than 1,000 m/yr, the
additional MSR caused by the last 120 years of deglaciation will continue to increase. |
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