Effects of present-day deglaciation in Iceland on mantle melt production rates

Ongoing deglaciation in Iceland not only causes uplift at the surface but also increases magma production at depth due to decompression of the mantle. Here we study glacially induced decompression melting using 3‐D models of glacial isostatic adjustment in Iceland since 1890. We find that the mean g...

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Bibliographic Details
Published in:Journal of Geophysical Research: Solid Earth
Main Authors: P. Schmidt, B. Lund, C. Hieronymus, J. Maclennan, T. Arnadottir, PAGLI, CAROLINA
Other Authors: P., Schmidt, B., Lund, C., Hieronymu, J., Maclennan, T., Arnadottir, Pagli, Carolina
Format: Article in Journal/Newspaper
Language:English
Published: 2013
Subjects:
decompression melting
GIA
Iceland
mantle melting
volcanism
deglaciation
Vatnajökull
Eyjafjallajökull
Ice cap
Online Access:http://hdl.handle.net/11568/500303
https://doi.org/10.1002/jgrb.50273
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/jgrb.50273
Description
Summary:Ongoing deglaciation in Iceland not only causes uplift at the surface but also increases magma production at depth due to decompression of the mantle. Here we study glacially induced decompression melting using 3‐D models of glacial isostatic adjustment in Iceland since 1890. We find that the mean glacially induced pressure rate of change in the mantle increases melt production rates by 100–135%, or an additional 0.21–0.23 km3 of magma per year beneath Iceland. Approximately 50% of this melt is produced underneath central Iceland. The greatest volumetric increase is found directly beneath Iceland's largest ice cap, Vatnajökull, colocated with the most productive volcanoes. Our models of the effect of deglaciation on mantle melting predict a significantly larger volumetric response than previous models which only considered the effect of deglaciation of Vatnajökull, and only mantle melting directly below Vatnajökull. Although the ongoing deglaciation significantly increases the melt production rate, the increase in melt supply rate at the base of the lithosphere is delayed and depends on the melt ascent velocity through the mantle. Assuming that 25% of the melt reaches the surface, the upper limit on our deglaciation‐induced melt estimates for central Iceland would be equivalent to an eruption the size of the 2010 Eyjafjallajökull summit eruption every seventh year.

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