Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland
In 2009 the IDDP-1 borehole at Krafla, Iceland unexpectedly intersected rhyolitic magma at 2.1 km depth [1,2], providing unprecedented opportunities to investigate silicic melt formation and storage, and potential for powerful geothermal energy production. A key objective is to constrain the nature...
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ftulancaster:oai:eprints.lancs.ac.uk:83119 2023-08-27T04:10:10+02:00 Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland Trewick, Laura Tuffen, Hugh Owen, Jacqueline Kennedy, Ben M. Eichelberger, John Zierenberg, Robert 2016-04-15 https://eprints.lancs.ac.uk/id/eprint/83119/ unknown European Geosciences Union Trewick, Laura and Tuffen, Hugh and Owen, Jacqueline and Kennedy, Ben M. and Eichelberger, John and Zierenberg, Robert (2016) Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland. In: Geophysical Research Abstracts. European Geosciences Union. Contribution in Book/Report/Proceedings PeerReviewed 2016 ftulancaster 2023-08-03T22:30:30Z In 2009 the IDDP-1 borehole at Krafla, Iceland unexpectedly intersected rhyolitic magma at 2.1 km depth [1,2], providing unprecedented opportunities to investigate silicic melt formation and storage, and potential for powerful geothermal energy production. A key objective is to constrain the nature of the rhyolitic melt and its response to drilling. As no intact core was extracted, evidence is fragmental - from glassy rhyolitic clasts retrieved from the cuttings. These exhibit a range of glass colours, vesicularities and phenocryst contents [1,2]. Here we use benchtop infra-red spectroscopy and petrological microscopy to characterise the H2O concentrations and bubble number densities within diverse glassy clasts, complemented by 1 Atm bubble growth experiments with a heated stage to investigate vesicle growth. Juvenile glassy clasts were divided into three categories (brown>banded>very dark glass). H2O concentrations within clasts showed some spatial variability, with enrichment towards bubble-rich areas that may be resorption-related but could not be adequately characterised with a benchtop source. However, mean values ranged from 1.41-1.68 wt %, with no statistically significant difference between clast types. This is broadly consistent with previous studies [1,2]. Bubble growth rates in all clast types were determined during isothermal dwells at 600, 650 and 700 C, for which bubbles grew at 0.03-0.09, 0.11-0.31, and 0.46-0.82 m s-1 respectively. The highest growth rates were measured for the most water-rich clast analysed - a banded clast with mean H2O of 1.68 wt %, and initially-larger bubbles also grew more rapidly. Measured bubble number densities (BNDs) range from 10[11.7] m-3 in banded clasts to 10[13.1] m-3 in very dark clasts, corresponding to decompression rates of 0.1-1 MPa/s [3], although experimentation on IDDP-1 magma is needed to properly calibrate BNDs as a decompression rate meter. Nonetheless, such decompression rates suggest nucleation occurred over tens-hundreds of seconds, as pressure ... Text Iceland Lancaster University: Lancaster Eprints Krafla ENVELOPE(-16.747,-16.747,65.713,65.713) |
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Lancaster University: Lancaster Eprints |
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ftulancaster |
language |
unknown |
description |
In 2009 the IDDP-1 borehole at Krafla, Iceland unexpectedly intersected rhyolitic magma at 2.1 km depth [1,2], providing unprecedented opportunities to investigate silicic melt formation and storage, and potential for powerful geothermal energy production. A key objective is to constrain the nature of the rhyolitic melt and its response to drilling. As no intact core was extracted, evidence is fragmental - from glassy rhyolitic clasts retrieved from the cuttings. These exhibit a range of glass colours, vesicularities and phenocryst contents [1,2]. Here we use benchtop infra-red spectroscopy and petrological microscopy to characterise the H2O concentrations and bubble number densities within diverse glassy clasts, complemented by 1 Atm bubble growth experiments with a heated stage to investigate vesicle growth. Juvenile glassy clasts were divided into three categories (brown>banded>very dark glass). H2O concentrations within clasts showed some spatial variability, with enrichment towards bubble-rich areas that may be resorption-related but could not be adequately characterised with a benchtop source. However, mean values ranged from 1.41-1.68 wt %, with no statistically significant difference between clast types. This is broadly consistent with previous studies [1,2]. Bubble growth rates in all clast types were determined during isothermal dwells at 600, 650 and 700 C, for which bubbles grew at 0.03-0.09, 0.11-0.31, and 0.46-0.82 m s-1 respectively. The highest growth rates were measured for the most water-rich clast analysed - a banded clast with mean H2O of 1.68 wt %, and initially-larger bubbles also grew more rapidly. Measured bubble number densities (BNDs) range from 10[11.7] m-3 in banded clasts to 10[13.1] m-3 in very dark clasts, corresponding to decompression rates of 0.1-1 MPa/s [3], although experimentation on IDDP-1 magma is needed to properly calibrate BNDs as a decompression rate meter. Nonetheless, such decompression rates suggest nucleation occurred over tens-hundreds of seconds, as pressure ... |
format |
Text |
author |
Trewick, Laura Tuffen, Hugh Owen, Jacqueline Kennedy, Ben M. Eichelberger, John Zierenberg, Robert |
spellingShingle |
Trewick, Laura Tuffen, Hugh Owen, Jacqueline Kennedy, Ben M. Eichelberger, John Zierenberg, Robert Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland |
author_facet |
Trewick, Laura Tuffen, Hugh Owen, Jacqueline Kennedy, Ben M. Eichelberger, John Zierenberg, Robert |
author_sort |
Trewick, Laura |
title |
Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland |
title_short |
Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland |
title_full |
Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland |
title_fullStr |
Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland |
title_full_unstemmed |
Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland |
title_sort |
vesiculation of rhyolite magma in the iddp-1 borehole at krafla, iceland |
publisher |
European Geosciences Union |
publishDate |
2016 |
url |
https://eprints.lancs.ac.uk/id/eprint/83119/ |
long_lat |
ENVELOPE(-16.747,-16.747,65.713,65.713) |
geographic |
Krafla |
geographic_facet |
Krafla |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
Trewick, Laura and Tuffen, Hugh and Owen, Jacqueline and Kennedy, Ben M. and Eichelberger, John and Zierenberg, Robert (2016) Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland. In: Geophysical Research Abstracts. European Geosciences Union. |
_version_ |
1775351997054058496 |