An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions
International audience The brittle to ductile transition (BDT) in rocks may strongly influence their transport properties (i.e., permeability, porosity topology .) and the maximum depth and temperature where hydrothermal fluids may circulate. To examine this transition in the context of Icelandic cr...
Published in: | Journal of Geophysical Research: Solid Earth |
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Format: | Article in Journal/Newspaper |
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Online Access: | https://hal.science/hal-00760905 https://hal.science/hal-00760905/document https://hal.science/hal-00760905/file/2011JB008884.pdf https://doi.org/10.1029/2011JB008884 |
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ftinsu:oai:HAL:hal-00760905v1 2023-06-18T03:41:26+02:00 An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions Violay, Marie Gibert, Benoit Mainprice, David Evans, Brian Dautria, Jean-Marie Azais, Pierre Pezard, Philippe Géosciences Montpellier Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Massachusetts Institute of Technology (MIT) 2012 https://hal.science/hal-00760905 https://hal.science/hal-00760905/document https://hal.science/hal-00760905/file/2011JB008884.pdf https://doi.org/10.1029/2011JB008884 en eng HAL CCSD American Geophysical Union info:eu-repo/semantics/altIdentifier/doi/10.1029/2011JB008884 hal-00760905 https://hal.science/hal-00760905 https://hal.science/hal-00760905/document https://hal.science/hal-00760905/file/2011JB008884.pdf doi:10.1029/2011JB008884 info:eu-repo/semantics/OpenAccess ISSN: 0148-0227 EISSN: 2156-2202 Journal of Geophysical Research https://hal.science/hal-00760905 Journal of Geophysical Research, 2012, 117, pp.B03213. ⟨10.1029/2011JB008884⟩ basalt brittle to ductile transition experimental deformation hydrothermal circulation [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes info:eu-repo/semantics/article Journal articles 2012 ftinsu https://doi.org/10.1029/2011JB008884 2023-06-05T21:38:33Z International audience The brittle to ductile transition (BDT) in rocks may strongly influence their transport properties (i.e., permeability, porosity topology .) and the maximum depth and temperature where hydrothermal fluids may circulate. To examine this transition in the context of Icelandic crust, we conducted deformation experiments on a glassy basalt (GB) and a glass-free basalt (GFB) under oceanic crust conditions. Mechanical and micro-structural observations at a constant strain rate of 10(-5) s(-1) and at confining pressure of 100-300 MPa indicate that the rocks are brittle and dilatant up to 700-800 degrees C. At higher temperatures and effective pressures the deformation mode becomes macroscopically ductile, i.e., deformation is distributed throughout the sample and no localized shear rupture plane develops. The presence of glass is a key component reducing the sample strength and lowering the pressure of the BDT. In the brittle field, strength is consistent with a Mohr-Coulomb failure criterion with an internal coefficient of friction of 0.42 for both samples. In the ductile field, strength is strain rate-and temperature-dependent and both samples were characterized by the same stress exponent in the range 3 < n < 4.2 but by very different activation energy Q(GB) = 59 +/- 15 KJ/mol and Q(GFB) = 456 +/- 4 KJ/mol. Extrapolation of these results to the Iceland oceanic crust conditions predicts a BDT at similar to 100 degrees C for a glassy basalt, whereas the BDT might occur in non-glassy basalts at deeper conditions, i.e., temperatures higher than 550 +/- 100 degrees C, in agreement with the Icelandic seismogenic zone. Article in Journal/Newspaper Iceland Institut national des sciences de l'Univers: HAL-INSU Journal of Geophysical Research: Solid Earth 117 B3 |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
basalt brittle to ductile transition experimental deformation hydrothermal circulation [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes |
spellingShingle |
basalt brittle to ductile transition experimental deformation hydrothermal circulation [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes Violay, Marie Gibert, Benoit Mainprice, David Evans, Brian Dautria, Jean-Marie Azais, Pierre Pezard, Philippe An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions |
topic_facet |
basalt brittle to ductile transition experimental deformation hydrothermal circulation [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes |
description |
International audience The brittle to ductile transition (BDT) in rocks may strongly influence their transport properties (i.e., permeability, porosity topology .) and the maximum depth and temperature where hydrothermal fluids may circulate. To examine this transition in the context of Icelandic crust, we conducted deformation experiments on a glassy basalt (GB) and a glass-free basalt (GFB) under oceanic crust conditions. Mechanical and micro-structural observations at a constant strain rate of 10(-5) s(-1) and at confining pressure of 100-300 MPa indicate that the rocks are brittle and dilatant up to 700-800 degrees C. At higher temperatures and effective pressures the deformation mode becomes macroscopically ductile, i.e., deformation is distributed throughout the sample and no localized shear rupture plane develops. The presence of glass is a key component reducing the sample strength and lowering the pressure of the BDT. In the brittle field, strength is consistent with a Mohr-Coulomb failure criterion with an internal coefficient of friction of 0.42 for both samples. In the ductile field, strength is strain rate-and temperature-dependent and both samples were characterized by the same stress exponent in the range 3 < n < 4.2 but by very different activation energy Q(GB) = 59 +/- 15 KJ/mol and Q(GFB) = 456 +/- 4 KJ/mol. Extrapolation of these results to the Iceland oceanic crust conditions predicts a BDT at similar to 100 degrees C for a glassy basalt, whereas the BDT might occur in non-glassy basalts at deeper conditions, i.e., temperatures higher than 550 +/- 100 degrees C, in agreement with the Icelandic seismogenic zone. |
author2 |
Géosciences Montpellier Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Massachusetts Institute of Technology (MIT) |
format |
Article in Journal/Newspaper |
author |
Violay, Marie Gibert, Benoit Mainprice, David Evans, Brian Dautria, Jean-Marie Azais, Pierre Pezard, Philippe |
author_facet |
Violay, Marie Gibert, Benoit Mainprice, David Evans, Brian Dautria, Jean-Marie Azais, Pierre Pezard, Philippe |
author_sort |
Violay, Marie |
title |
An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions |
title_short |
An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions |
title_full |
An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions |
title_fullStr |
An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions |
title_full_unstemmed |
An experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions |
title_sort |
experimental study of the brittle-ductile transition of basalt at oceanic crust pressure and temperature conditions |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://hal.science/hal-00760905 https://hal.science/hal-00760905/document https://hal.science/hal-00760905/file/2011JB008884.pdf https://doi.org/10.1029/2011JB008884 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
ISSN: 0148-0227 EISSN: 2156-2202 Journal of Geophysical Research https://hal.science/hal-00760905 Journal of Geophysical Research, 2012, 117, pp.B03213. ⟨10.1029/2011JB008884⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2011JB008884 hal-00760905 https://hal.science/hal-00760905 https://hal.science/hal-00760905/document https://hal.science/hal-00760905/file/2011JB008884.pdf doi:10.1029/2011JB008884 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2011JB008884 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
117 |
container_issue |
B3 |
_version_ |
1769007007111577600 |