The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions
Magma degassing patterns can potentially be used to reconstruct ice thicknesses during subglacial eruptions, as the pressure dependence of water solubility in silicate melts is reasonably well constrained. The amount of water remaining in the quenched bulk glasses should record the quenching pressur...
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ftulancaster:oai:eprints.lancs.ac.uk:52155 2023-08-27T04:10:01+02:00 The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions Owen, Jacqueline Tuffen, Hugh McGarvie, DW Pinkerton, Harry Wilson, Lionel 2010-05-01 https://eprints.lancs.ac.uk/id/eprint/52155/ unknown Owen, Jacqueline and Tuffen, Hugh and McGarvie, DW and Pinkerton, Harry and Wilson, Lionel (2010) The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions. In: EGU General Assembly 2010, 2010-05-01. Contribution to Conference NonPeerReviewed 2010 ftulancaster 2023-08-03T22:21:38Z Magma degassing patterns can potentially be used to reconstruct ice thicknesses during subglacial eruptions, as the pressure dependence of water solubility in silicate melts is reasonably well constrained. The amount of water remaining in the quenched bulk glasses should record the quenching pressure, which, in a subglacial setting, will be dependent on the pressure of overlying ice and/or meltwater that was present. This reconstruction technique has been applied to several basaltic volcanoes[1]. In one study the dissolved water contents was seen to vary as a function of altitude, consistent with the presence of an ice sheet[2]. Similar techniques have been applied to a rhyolitic volcano, as described below. Bláhnúkur is a small-volume rhyolitic, subglacial volcano at Torfajökull volcano, southern Iceland[3] that erupted at 95 ka[4]. 45 glassy lava samples were collected from a variety of elevations and lithofacies types. These samples were analysed for water content using infra-red spectroscopy (FTIR), and pressure-solubility relationships were calculated using VolatileCalc[5]. The results reveal a general decrease in water concentration with elevation, consistent with the presence of an ice sheet with a surface elevation of 1,050 m a.s.l. This corresponds with an ice thickness of 450 m, consistent with the field evidence from tuyas of a similar age within the same region[6]. Furthermore, the results suggest an eruptive temperature of 850°C and 0 ppm CO2. However, not all samples agree with this overall trend. We suggest that samples with anomalously low water contents could have formed in regions where there was meltwater drainage which lowered the quenching pressure[7]. By contrast, water-rich samples could reflect intrusive formation resulting in loading by rock as well as ice[8]. Crucially though, the anomalous values are all from the same locations, suggesting that there are processes that are specifically affecting certain localities. In order to use palaeo reconstruction methods, certain conditions need ... Conference Object Ice Sheet Iceland Lancaster University: Lancaster Eprints Bláhnúkur ENVELOPE(-19.069,-19.069,63.977,63.977) Torfajökull ENVELOPE(-19.027,-19.027,63.898,63.898) |
institution |
Open Polar |
collection |
Lancaster University: Lancaster Eprints |
op_collection_id |
ftulancaster |
language |
unknown |
description |
Magma degassing patterns can potentially be used to reconstruct ice thicknesses during subglacial eruptions, as the pressure dependence of water solubility in silicate melts is reasonably well constrained. The amount of water remaining in the quenched bulk glasses should record the quenching pressure, which, in a subglacial setting, will be dependent on the pressure of overlying ice and/or meltwater that was present. This reconstruction technique has been applied to several basaltic volcanoes[1]. In one study the dissolved water contents was seen to vary as a function of altitude, consistent with the presence of an ice sheet[2]. Similar techniques have been applied to a rhyolitic volcano, as described below. Bláhnúkur is a small-volume rhyolitic, subglacial volcano at Torfajökull volcano, southern Iceland[3] that erupted at 95 ka[4]. 45 glassy lava samples were collected from a variety of elevations and lithofacies types. These samples were analysed for water content using infra-red spectroscopy (FTIR), and pressure-solubility relationships were calculated using VolatileCalc[5]. The results reveal a general decrease in water concentration with elevation, consistent with the presence of an ice sheet with a surface elevation of 1,050 m a.s.l. This corresponds with an ice thickness of 450 m, consistent with the field evidence from tuyas of a similar age within the same region[6]. Furthermore, the results suggest an eruptive temperature of 850°C and 0 ppm CO2. However, not all samples agree with this overall trend. We suggest that samples with anomalously low water contents could have formed in regions where there was meltwater drainage which lowered the quenching pressure[7]. By contrast, water-rich samples could reflect intrusive formation resulting in loading by rock as well as ice[8]. Crucially though, the anomalous values are all from the same locations, suggesting that there are processes that are specifically affecting certain localities. In order to use palaeo reconstruction methods, certain conditions need ... |
format |
Conference Object |
author |
Owen, Jacqueline Tuffen, Hugh McGarvie, DW Pinkerton, Harry Wilson, Lionel |
spellingShingle |
Owen, Jacqueline Tuffen, Hugh McGarvie, DW Pinkerton, Harry Wilson, Lionel The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions |
author_facet |
Owen, Jacqueline Tuffen, Hugh McGarvie, DW Pinkerton, Harry Wilson, Lionel |
author_sort |
Owen, Jacqueline |
title |
The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions |
title_short |
The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions |
title_full |
The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions |
title_fullStr |
The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions |
title_full_unstemmed |
The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions |
title_sort |
use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions |
publishDate |
2010 |
url |
https://eprints.lancs.ac.uk/id/eprint/52155/ |
long_lat |
ENVELOPE(-19.069,-19.069,63.977,63.977) ENVELOPE(-19.027,-19.027,63.898,63.898) |
geographic |
Bláhnúkur Torfajökull |
geographic_facet |
Bláhnúkur Torfajökull |
genre |
Ice Sheet Iceland |
genre_facet |
Ice Sheet Iceland |
op_relation |
Owen, Jacqueline and Tuffen, Hugh and McGarvie, DW and Pinkerton, Harry and Wilson, Lionel (2010) The use of magmatic water to reconstruct palaeo-ice thicknesses during subglacial rhyolitic eruptions. In: EGU General Assembly 2010, 2010-05-01. |
_version_ |
1775351761756749824 |