Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations
Abstract Plagioclase‐rich granulites exposed on the Lofoten archipelago, Northern Norway, display strain localization in pseudotachylytes as well as ductile shear zones that formed under similar high‐pressure and high‐temperature conditions. Pseudotachylytes or pseudotachylyte networks reveal no or...
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ftdoajarticles:oai:doaj.org/article:60034f088d8f4d838bc6f91855de2612 2023-12-03T10:25:36+01:00 Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations Sarah Incel Jörg Renner Bjørn Jamtveit 2020-08-01T00:00:00Z https://doi.org/10.1029/2020GC009028 https://doaj.org/article/60034f088d8f4d838bc6f91855de2612 EN eng Wiley https://doi.org/10.1029/2020GC009028 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2020GC009028 https://doaj.org/article/60034f088d8f4d838bc6f91855de2612 Geochemistry, Geophysics, Geosystems, Vol 21, Iss 8, Pp n/a-n/a (2020) semibrittle deformation of plagioclase Griggs‐deformation experiments microstructures pseudotachylytes ductile shear zones Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.1029/2020GC009028 2023-11-05T01:36:02Z Abstract Plagioclase‐rich granulites exposed on the Lofoten archipelago, Northern Norway, display strain localization in pseudotachylytes as well as ductile shear zones that formed under similar high‐pressure and high‐temperature conditions. Pseudotachylytes or pseudotachylyte networks reveal no or very little hydration, whereas ductile shear zones reveal significant hydration. We combine these observations from the field with experimental results to characterize the structural evolution of brittle faults in plagioclase‐rich rocks at conditions of the lower continental crust. We performed a series of deformation experiments on intact granulite samples prepared from a natural granulite sample at 2.5 GPa confining pressure, a strain rate of 5 × 10−5 s−1, and temperatures of 700°C and 900°C to total strains of ~7–8% and ~33–36%. Samples were either deformed “as‐is” or with ~1 wt.% H2O added. Striking similarities between the experimental and natural microstructures suggest that the transformation of precursory brittle structures into ductile shear zones at eclogite‐facies conditions is most effective in samples deformed with added water triggering reaction and subsequent plastic deformation of the products along the faults and in the adjacent wall‐rock. Article in Journal/Newspaper Lofoten Northern Norway Directory of Open Access Journals: DOAJ Articles Lofoten Norway Geochemistry, Geophysics, Geosystems 21 8 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
semibrittle deformation of plagioclase Griggs‐deformation experiments microstructures pseudotachylytes ductile shear zones Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
spellingShingle |
semibrittle deformation of plagioclase Griggs‐deformation experiments microstructures pseudotachylytes ductile shear zones Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 Sarah Incel Jörg Renner Bjørn Jamtveit Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations |
topic_facet |
semibrittle deformation of plagioclase Griggs‐deformation experiments microstructures pseudotachylytes ductile shear zones Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
description |
Abstract Plagioclase‐rich granulites exposed on the Lofoten archipelago, Northern Norway, display strain localization in pseudotachylytes as well as ductile shear zones that formed under similar high‐pressure and high‐temperature conditions. Pseudotachylytes or pseudotachylyte networks reveal no or very little hydration, whereas ductile shear zones reveal significant hydration. We combine these observations from the field with experimental results to characterize the structural evolution of brittle faults in plagioclase‐rich rocks at conditions of the lower continental crust. We performed a series of deformation experiments on intact granulite samples prepared from a natural granulite sample at 2.5 GPa confining pressure, a strain rate of 5 × 10−5 s−1, and temperatures of 700°C and 900°C to total strains of ~7–8% and ~33–36%. Samples were either deformed “as‐is” or with ~1 wt.% H2O added. Striking similarities between the experimental and natural microstructures suggest that the transformation of precursory brittle structures into ductile shear zones at eclogite‐facies conditions is most effective in samples deformed with added water triggering reaction and subsequent plastic deformation of the products along the faults and in the adjacent wall‐rock. |
format |
Article in Journal/Newspaper |
author |
Sarah Incel Jörg Renner Bjørn Jamtveit |
author_facet |
Sarah Incel Jörg Renner Bjørn Jamtveit |
author_sort |
Sarah Incel |
title |
Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations |
title_short |
Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations |
title_full |
Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations |
title_fullStr |
Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations |
title_full_unstemmed |
Evolution of Brittle Structures in Plagioclase‐Rich Rocks at High‐Pressure and High‐Temperature Conditions—Linking Laboratory Results to Field Observations |
title_sort |
evolution of brittle structures in plagioclase‐rich rocks at high‐pressure and high‐temperature conditions—linking laboratory results to field observations |
publisher |
Wiley |
publishDate |
2020 |
url |
https://doi.org/10.1029/2020GC009028 https://doaj.org/article/60034f088d8f4d838bc6f91855de2612 |
geographic |
Lofoten Norway |
geographic_facet |
Lofoten Norway |
genre |
Lofoten Northern Norway |
genre_facet |
Lofoten Northern Norway |
op_source |
Geochemistry, Geophysics, Geosystems, Vol 21, Iss 8, Pp n/a-n/a (2020) |
op_relation |
https://doi.org/10.1029/2020GC009028 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2020GC009028 https://doaj.org/article/60034f088d8f4d838bc6f91855de2612 |
op_doi |
https://doi.org/10.1029/2020GC009028 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
21 |
container_issue |
8 |
_version_ |
1784274561597964288 |