Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature
International audience Grain size sensitive creep (GSSC) mechanisms are widely recognized to be the most efficient deformation mechanisms in shear zones. With or without initial fracturing and fluid infiltration, the onset of heterogeneous nucleation leading to strong grain size reduction is a frequ...
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HAL CCSD
2017
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Online Access: | https://hal.science/hal-03552762 https://hal.science/hal-03552762/document https://hal.science/hal-03552762/file/EGU2017-3203.pdf |
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Institut national des sciences de l'Univers: HAL-INSU |
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English |
topic |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
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[SDU.STU]Sciences of the Universe [physics]/Earth Sciences Marti, Sina Heilbronner, Renée Stünitz, Holger Plümper, Oliver Drury, Martyn Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature |
topic_facet |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience Grain size sensitive creep (GSSC) mechanisms are widely recognized to be the most efficient deformation mechanisms in shear zones. With or without initial fracturing and fluid infiltration, the onset of heterogeneous nucleation leading to strong grain size reduction is a frequently described process for the initiation of GSSC. Phase mixing due to reaction and heterogeneous nucleation during GSSC impedes grain growth, sustaining small grain sizes as a prerequisite for GSSC. Here we present rock deformation experiments on 'wet' plagioclase - pyroxene mixtures at T=800°C, P=1.0 and 1.5GPa and strain rates of 2e-5 - 2e-6 1/s, performed with a Griggs-type solid medium deformation apparatus. Microstructural criteria are used to show that both, grain boundary sliding (GBS) and solution-mass transfer processes are active and are interpreted to be the dominant strain accommodating processes. Displacement is localized within shear bands formed by fine-grained ( 300 - 500nm) plagioclase (Pl) and the syn-kinematic reaction products amphibole (Amph), quartz (Qz) and zoisite (Zo). We compare our experiments with a natural case - a sheared mafic pegmatite (P-T during deformation 0.7 - 0.9 GPa, 610 - 710 °C; Getsinger et al., 2013) from Northern Norway. Except for the difference in grain size of the experimental and natural samples, microstructures are strikingly alike. The experimental and natural P- and especially T-conditions are very similar. Consequently, extrapolation from experiments to nature must be made without a significant 'temperature-time' trade-off, which is normally taken advantage of when relating experimental to natural strain rates. We will discuss under which assumptions extrapolation to nature in our case is likely feasible. Syn-kinematic reactions during GBS and solution-mass transport are commonly interpreted to result in an ordered (anticlustered) phase mixture. However, phase mixing in our case is restricted: Mixing is extensive between Pl + Zo + Qz and Amph + Qz, but clustering ... |
author2 |
Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO) Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS) Géodynamique - UMR7327 Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS) |
format |
Conference Object |
author |
Marti, Sina Heilbronner, Renée Stünitz, Holger Plümper, Oliver Drury, Martyn |
author_facet |
Marti, Sina Heilbronner, Renée Stünitz, Holger Plümper, Oliver Drury, Martyn |
author_sort |
Marti, Sina |
title |
Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature |
title_short |
Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature |
title_full |
Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature |
title_fullStr |
Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature |
title_full_unstemmed |
Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature |
title_sort |
solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://hal.science/hal-03552762 https://hal.science/hal-03552762/document https://hal.science/hal-03552762/file/EGU2017-3203.pdf |
op_coverage |
Vienne, Austria |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Northern Norway |
genre_facet |
Northern Norway |
op_source |
19th EGU General Assembly https://hal.science/hal-03552762 19th EGU General Assembly, 2017, Vienne, Austria. pp.3203 |
op_relation |
hal-03552762 https://hal.science/hal-03552762 https://hal.science/hal-03552762/document https://hal.science/hal-03552762/file/EGU2017-3203.pdf BIBCODE: 2017EGUGA.19.3203M |
op_rights |
http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess |
_version_ |
1788063921358241792 |
spelling |
ftinsu:oai:HAL:hal-03552762v1 2024-01-14T10:09:24+01:00 Solution-mass transfer and grain boundary sliding in mafic shear zones - comparison between experiments and nature Marti, Sina Heilbronner, Renée Stünitz, Holger Plümper, Oliver Drury, Martyn Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO) Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS) Géodynamique - UMR7327 Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS) Vienne, Austria 2017 https://hal.science/hal-03552762 https://hal.science/hal-03552762/document https://hal.science/hal-03552762/file/EGU2017-3203.pdf en eng HAL CCSD hal-03552762 https://hal.science/hal-03552762 https://hal.science/hal-03552762/document https://hal.science/hal-03552762/file/EGU2017-3203.pdf BIBCODE: 2017EGUGA.19.3203M http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess 19th EGU General Assembly https://hal.science/hal-03552762 19th EGU General Assembly, 2017, Vienne, Austria. pp.3203 [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/conferenceObject Conference papers 2017 ftinsu 2023-12-20T17:24:35Z International audience Grain size sensitive creep (GSSC) mechanisms are widely recognized to be the most efficient deformation mechanisms in shear zones. With or without initial fracturing and fluid infiltration, the onset of heterogeneous nucleation leading to strong grain size reduction is a frequently described process for the initiation of GSSC. Phase mixing due to reaction and heterogeneous nucleation during GSSC impedes grain growth, sustaining small grain sizes as a prerequisite for GSSC. Here we present rock deformation experiments on 'wet' plagioclase - pyroxene mixtures at T=800°C, P=1.0 and 1.5GPa and strain rates of 2e-5 - 2e-6 1/s, performed with a Griggs-type solid medium deformation apparatus. Microstructural criteria are used to show that both, grain boundary sliding (GBS) and solution-mass transfer processes are active and are interpreted to be the dominant strain accommodating processes. Displacement is localized within shear bands formed by fine-grained ( 300 - 500nm) plagioclase (Pl) and the syn-kinematic reaction products amphibole (Amph), quartz (Qz) and zoisite (Zo). We compare our experiments with a natural case - a sheared mafic pegmatite (P-T during deformation 0.7 - 0.9 GPa, 610 - 710 °C; Getsinger et al., 2013) from Northern Norway. Except for the difference in grain size of the experimental and natural samples, microstructures are strikingly alike. The experimental and natural P- and especially T-conditions are very similar. Consequently, extrapolation from experiments to nature must be made without a significant 'temperature-time' trade-off, which is normally taken advantage of when relating experimental to natural strain rates. We will discuss under which assumptions extrapolation to nature in our case is likely feasible. Syn-kinematic reactions during GBS and solution-mass transport are commonly interpreted to result in an ordered (anticlustered) phase mixture. However, phase mixing in our case is restricted: Mixing is extensive between Pl + Zo + Qz and Amph + Qz, but clustering ... Conference Object Northern Norway Institut national des sciences de l'Univers: HAL-INSU Norway |