Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks
Shallow silicic intrusions are known to exist in many active volcanoes and can fuel both eruptions and hydrothermal fields. However, our knowledge of magma intrusions remains far from complete, and processes occurring at intrusion margins are poorly understood. In this field-based study, we characte...
Published in: | Journal of Volcanology and Geothermal Research |
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Language: | English |
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Online Access: | http://hdl.handle.net/10092/17788 https://doi.org/10.1016/j.jvolgeores.2019.106691 |
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ftunivcanter:oai:ir.canterbury.ac.nz:10092/17788 2023-05-15T16:47:31+02:00 Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks Saubin E Kennedy B Tuffen H Villeneuve M Davidson J Burchardt S 2019-11-04T16:10:38Z application/pdf http://hdl.handle.net/10092/17788 https://doi.org/10.1016/j.jvolgeores.2019.106691 English en eng Elsevier BV Saubin E, Kennedy B, Tuffen H, Villeneuve M, Davidson J, Burchardt S (2019). Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks. Journal of Volcanology and Geothermal Research. 106691-106691. 0377-0273 http://hdl.handle.net/10092/17788 https://doi.org/10.1016/j.jvolgeores.2019.106691 Rhyolite Intrusion Iceland Damage Emplacement Permeability Fields of Research::37 - Earth sciences::3705 - Geology::370503 - Igneous and metamorphic petrology Field of Research::04 - Earth Sciences::0403 - Geology::040312 - Structural Geology Fields of Research::37 - Earth sciences::3705 - Geology::370512 - Volcanology Journal Article 2019 ftunivcanter https://doi.org/10.1016/j.jvolgeores.2019.106691 2022-09-08T13:28:43Z Shallow silicic intrusions are known to exist in many active volcanoes and can fuel both eruptions and hydrothermal fields. However, our knowledge of magma intrusions remains far from complete, and processes occurring at intrusion margins are poorly understood. In this field-based study, we characterise four shallows, dissected rhyolitic intrusions at three sites in Iceland (Njarðvík-Dyrfjöll, Krafla and Húsafell central volcanoes). We focus on the relationship between intrusion emplacement mechanisms and country rock response, employing scanline mapping of fractures and in-situ rock property measurements (hardness and permeability) along transects from the intrusion margins to damaged and undamaged country rocks. We identify various scenarios of shallow intrusion emplacement style, based upon their diverse geometry and lithofacies architecture. Additional information from rock properties and characteristics of fractures and vesicles, indicates that initial country rock properties strongly influence the emplacement style. We identify two discrete types of country rock response to magma injection. The matrix permeability of weak, porous and permeable lithologies (conglomerate and hyaloclastite) is reduced by >1 order of magnitude adjacent to intrusions due to pore occlusion. Stronger and denser, low-permeability lithologies (basalt and welded ignimbrite) undergo a decrease in hardness by a factor >2 related to an up to fivefold increase in fracture density, with no significant change in matrix permeability. Our observations highlight the importance of robust characterisation of the mechanical properties of caldera-filling or geothermal reservoir formations, for appropriate forecasting of magma mobility, geophysical data interpretation, and geothermal resources characterisation. Article in Journal/Newspaper Iceland University of Canterbury, Christchurch: UC Research Repository Dyrfjöll ENVELOPE(-13.958,-13.958,65.521,65.521) Krafla ENVELOPE(-16.747,-16.747,65.713,65.713) Journal of Volcanology and Geothermal Research 388 106691 |
institution |
Open Polar |
collection |
University of Canterbury, Christchurch: UC Research Repository |
op_collection_id |
ftunivcanter |
language |
English |
topic |
Rhyolite Intrusion Iceland Damage Emplacement Permeability Fields of Research::37 - Earth sciences::3705 - Geology::370503 - Igneous and metamorphic petrology Field of Research::04 - Earth Sciences::0403 - Geology::040312 - Structural Geology Fields of Research::37 - Earth sciences::3705 - Geology::370512 - Volcanology |
spellingShingle |
Rhyolite Intrusion Iceland Damage Emplacement Permeability Fields of Research::37 - Earth sciences::3705 - Geology::370503 - Igneous and metamorphic petrology Field of Research::04 - Earth Sciences::0403 - Geology::040312 - Structural Geology Fields of Research::37 - Earth sciences::3705 - Geology::370512 - Volcanology Saubin E Kennedy B Tuffen H Villeneuve M Davidson J Burchardt S Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks |
topic_facet |
Rhyolite Intrusion Iceland Damage Emplacement Permeability Fields of Research::37 - Earth sciences::3705 - Geology::370503 - Igneous and metamorphic petrology Field of Research::04 - Earth Sciences::0403 - Geology::040312 - Structural Geology Fields of Research::37 - Earth sciences::3705 - Geology::370512 - Volcanology |
description |
Shallow silicic intrusions are known to exist in many active volcanoes and can fuel both eruptions and hydrothermal fields. However, our knowledge of magma intrusions remains far from complete, and processes occurring at intrusion margins are poorly understood. In this field-based study, we characterise four shallows, dissected rhyolitic intrusions at three sites in Iceland (Njarðvík-Dyrfjöll, Krafla and Húsafell central volcanoes). We focus on the relationship between intrusion emplacement mechanisms and country rock response, employing scanline mapping of fractures and in-situ rock property measurements (hardness and permeability) along transects from the intrusion margins to damaged and undamaged country rocks. We identify various scenarios of shallow intrusion emplacement style, based upon their diverse geometry and lithofacies architecture. Additional information from rock properties and characteristics of fractures and vesicles, indicates that initial country rock properties strongly influence the emplacement style. We identify two discrete types of country rock response to magma injection. The matrix permeability of weak, porous and permeable lithologies (conglomerate and hyaloclastite) is reduced by >1 order of magnitude adjacent to intrusions due to pore occlusion. Stronger and denser, low-permeability lithologies (basalt and welded ignimbrite) undergo a decrease in hardness by a factor >2 related to an up to fivefold increase in fracture density, with no significant change in matrix permeability. Our observations highlight the importance of robust characterisation of the mechanical properties of caldera-filling or geothermal reservoir formations, for appropriate forecasting of magma mobility, geophysical data interpretation, and geothermal resources characterisation. |
format |
Article in Journal/Newspaper |
author |
Saubin E Kennedy B Tuffen H Villeneuve M Davidson J Burchardt S |
author_facet |
Saubin E Kennedy B Tuffen H Villeneuve M Davidson J Burchardt S |
author_sort |
Saubin E |
title |
Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks |
title_short |
Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks |
title_full |
Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks |
title_fullStr |
Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks |
title_full_unstemmed |
Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks |
title_sort |
comparative field study of shallow rhyolite intrusions in iceland: emplacement mechanisms and impact on country rocks |
publisher |
Elsevier BV |
publishDate |
2019 |
url |
http://hdl.handle.net/10092/17788 https://doi.org/10.1016/j.jvolgeores.2019.106691 |
long_lat |
ENVELOPE(-13.958,-13.958,65.521,65.521) ENVELOPE(-16.747,-16.747,65.713,65.713) |
geographic |
Dyrfjöll Krafla |
geographic_facet |
Dyrfjöll Krafla |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
Saubin E, Kennedy B, Tuffen H, Villeneuve M, Davidson J, Burchardt S (2019). Comparative field study of shallow rhyolite intrusions in Iceland: emplacement mechanisms and impact on country rocks. Journal of Volcanology and Geothermal Research. 106691-106691. 0377-0273 http://hdl.handle.net/10092/17788 https://doi.org/10.1016/j.jvolgeores.2019.106691 |
op_doi |
https://doi.org/10.1016/j.jvolgeores.2019.106691 |
container_title |
Journal of Volcanology and Geothermal Research |
container_volume |
388 |
container_start_page |
106691 |
_version_ |
1766037614186463232 |