uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Effects of present day deglaciation on melt production rates beneath Iceland
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
Department of Earth Sciences, University of Cambridge.
Show others and affiliations
2013 (English)In: Journal of Geophysical Research-Solid Earth, ISSN 2169-9313, Vol. 118, no 7, 3366-3379 p.Article in journal (Other academic) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2013. Vol. 118, no 7, 3366-3379 p.
Keyword [en]
decompression melting, GIA, Iceland, mantle melting, volcanism, deglaciation
National Category
Geophysics
Identifiers
URN: urn:nbn:se:uu:diva-169788DOI: 10.1002/jgrb.50273ISI: 000324952300008OAI: oai:DiVA.org:uu-169788DiVA: diva2:507695
Available from: 2012-03-06 Created: 2012-03-06 Last updated: 2013-11-04Bibliographically approved
In thesis
1. Glacial Isostatic Adjustment: Inferences on properties and processes in the upper mantle from 3D dynamical modeling
Open this publication in new window or tab >>Glacial Isostatic Adjustment: Inferences on properties and processes in the upper mantle from 3D dynamical modeling
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Observations of glacial isostatic adjustment (GIA) offers a powerful window into the properties of the Earth's interior. Combined with dynamical modeling of the GIA process we can use the observations to infer properties such as the elastic structure of the lithosphere, the rheology of the mantle and changes in the stress conditions in the Earth. This information aids our understanding of the long term evolution of the Earth, e.g. mantle convection, but also illuminates short term processes such as magma generation, earthquakes and shoreline migration. As present day warming trends causes glacier retreat world wide, GIA offers the opportunity to gain local insight into the Earth.

In this thesis I develop an implementation of the pre-stress advection term in finite element modeling. I apply this to current GIA in Iceland, and conclude that local variations in the elastic thickness of the lithosphere can potentially be detected close to the largest ice cap. I study the magnitude of dehydration stiffening in the uppermost Icelandic mantle. The results indicate that the increase in viscosity over the dry solidus is of small magnitude, implying a non-linear rheology in the uppermost mantle beneath Iceland. The present deglaciation in Iceland causes additional melting of the mantle. I find an increased melt production rate of 100-140% at present, although the melt supply rate at the base of the lithosphere is found to be delayed, with estimated present day perturbations ranging from neglible up to 120%.

In the last section of the thesis I focus on the role of ice sheet reconstructions in GIA modeling. I compare three reconstruction of the Weichselian ice sheet and discuss similarities and difference as well as the fit to present day uplift rates in Fennoscandia. The results provide input to improvements in the ice sheet models.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 83 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 906
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-169790 (URN)978-91-554-8294-7 (ISBN)
Public defence
2012-04-20, Hamberg, Geocentrum, Villavägen 16, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2012-03-29 Created: 2012-03-06 Last updated: 2012-04-19Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Schmidt, PeterLund, BjörnHieronymus, Christoph

Search in DiVA

By author/editor
Schmidt, PeterLund, BjörnHieronymus, Christoph
By organisation
Geophysics
Geophysics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 431 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf