Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation
Observations of the time lag between the last deglaciation and a surge in volcanic activity in Iceland constrain the average melt ascent velocity to be $\geq50$ $\mathrm{m/yr}$. Although existing theoretical work has explained why the surge in eruption rates increased $5$-$30$ fold from the steady-s...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/293028 2024-01-14T10:07:53+01:00 Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation Eksinchol, I Rudge, JF Maclennan, J 2019 application/pdf https://www.repository.cam.ac.uk/handle/1810/293028 https://doi.org/10.17863/CAM.40179 eng eng American Geophysical Union (AGU) http://dx.doi.org/10.1029/2019GC008222 Geochemistry, Geophysics, Geosystems https://www.repository.cam.ac.uk/handle/1810/293028 doi:10.17863/CAM.40179 All rights reserved Iceland glaciation mantle melting magma migration rare earth elements mid-ocean ridges Article 2019 ftunivcam https://doi.org/10.17863/CAM.40179 2023-12-21T23:28:30Z Observations of the time lag between the last deglaciation and a surge in volcanic activity in Iceland constrain the average melt ascent velocity to be $\geq50$ $\mathrm{m/yr}$. Although existing theoretical work has explained why the surge in eruption rates increased $5$-$30$ fold from the steady-state rates during the last deglaciation, they cannot account for large variations of Rare Earth Element (REE) concentrations in the Icelandic lavas. Lavas erupted during the last deglaciation are depleted in REEs by up to $70\%$; whereas, existing models, which assume instantaneous melt transport, can only produce at most $20\%$ depletion. Here, we develop a numerical model with finite melt ascent velocity and show that the variations of REEs are strongly dependent on the melt ascent velocity. When the average melt ascent velocity is $100$ $\mathrm{m/yr}$, the variation of $\mathrm{La}$ calculated by our model is comparable to that of the observations. In contrast, when the melt ascent velocity is $1,000$ $\mathrm{m/yr}$ or above, the model variation of $\mathrm{La}$ becomes significantly lower than observed, which explains why previous models with instantaneous melt transport did not reproduce the large variations. We provide the first model that takes account of the diachronous response of volcanism to deglaciation. We show by comparing our model calculations of the relative volumes of different eruption types (subglacial, finiglacial and postglacial) and the timing of the bursts in volcanic eruptions with the observations across different volcanic zones that the Icelandic average melt ascent velocity during the last deglaciation is likely to be $\sim100$ $\mathrm{m/yr}$. The Cambridge Trust and the Leverhulme Trust Article in Journal/Newspaper Iceland Apollo - University of Cambridge Repository |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Iceland glaciation mantle melting magma migration rare earth elements mid-ocean ridges |
spellingShingle |
Iceland glaciation mantle melting magma migration rare earth elements mid-ocean ridges Eksinchol, I Rudge, JF Maclennan, J Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation |
topic_facet |
Iceland glaciation mantle melting magma migration rare earth elements mid-ocean ridges |
description |
Observations of the time lag between the last deglaciation and a surge in volcanic activity in Iceland constrain the average melt ascent velocity to be $\geq50$ $\mathrm{m/yr}$. Although existing theoretical work has explained why the surge in eruption rates increased $5$-$30$ fold from the steady-state rates during the last deglaciation, they cannot account for large variations of Rare Earth Element (REE) concentrations in the Icelandic lavas. Lavas erupted during the last deglaciation are depleted in REEs by up to $70\%$; whereas, existing models, which assume instantaneous melt transport, can only produce at most $20\%$ depletion. Here, we develop a numerical model with finite melt ascent velocity and show that the variations of REEs are strongly dependent on the melt ascent velocity. When the average melt ascent velocity is $100$ $\mathrm{m/yr}$, the variation of $\mathrm{La}$ calculated by our model is comparable to that of the observations. In contrast, when the melt ascent velocity is $1,000$ $\mathrm{m/yr}$ or above, the model variation of $\mathrm{La}$ becomes significantly lower than observed, which explains why previous models with instantaneous melt transport did not reproduce the large variations. We provide the first model that takes account of the diachronous response of volcanism to deglaciation. We show by comparing our model calculations of the relative volumes of different eruption types (subglacial, finiglacial and postglacial) and the timing of the bursts in volcanic eruptions with the observations across different volcanic zones that the Icelandic average melt ascent velocity during the last deglaciation is likely to be $\sim100$ $\mathrm{m/yr}$. The Cambridge Trust and the Leverhulme Trust |
format |
Article in Journal/Newspaper |
author |
Eksinchol, I Rudge, JF Maclennan, J |
author_facet |
Eksinchol, I Rudge, JF Maclennan, J |
author_sort |
Eksinchol, I |
title |
Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation |
title_short |
Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation |
title_full |
Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation |
title_fullStr |
Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation |
title_full_unstemmed |
Rate of Melt Ascent Beneath Iceland From the Magmatic Response to Deglaciation |
title_sort |
rate of melt ascent beneath iceland from the magmatic response to deglaciation |
publisher |
American Geophysical Union (AGU) |
publishDate |
2019 |
url |
https://www.repository.cam.ac.uk/handle/1810/293028 https://doi.org/10.17863/CAM.40179 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/293028 doi:10.17863/CAM.40179 |
op_rights |
All rights reserved |
op_doi |
https://doi.org/10.17863/CAM.40179 |
_version_ |
1788062290905399296 |