Metamorphic evolution of the Great Slave Lake shear zone
<jats:title>Abstract</jats:title><jats:p>The Palaeoproterozoic Great Slave Lake shear zone (GSLsz) is a crustal‐scale strike‐slip structure, with a total length of >1,000 km and a width of ~25 km, that separates the Archean Rae and Slave cratons. The range of metamorphic rocks n...
Published in: | Sensors |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2021
|
Subjects: | |
Online Access: | https://www.repository.cam.ac.uk/handle/1810/311735 https://doi.org/10.17863/CAM.58825 |
id |
ftunivcam:oai:www.repository.cam.ac.uk:1810/311735 |
---|---|
record_format |
openpolar |
spelling |
ftunivcam:oai:www.repository.cam.ac.uk:1810/311735 2024-01-14T10:07:07+01:00 Metamorphic evolution of the Great Slave Lake shear zone Dyck, B Goddard, RM Wallis, D Hansen, LN Martel, E 2021 application/pdf https://www.repository.cam.ac.uk/handle/1810/311735 https://doi.org/10.17863/CAM.58825 eng eng Wiley http://dx.doi.org/10.1111/jmg.12576 Journal of Metamorphic Geology https://www.repository.cam.ac.uk/handle/1810/311735 doi:10.17863/CAM.58825 All rights reserved mylonite phase equilibria modelling shear zone thermometry Article 2021 ftunivcam https://doi.org/10.17863/CAM.58825 2023-12-21T23:27:39Z <jats:title>Abstract</jats:title><jats:p>The Palaeoproterozoic Great Slave Lake shear zone (GSLsz) is a crustal‐scale strike‐slip structure, with a total length of >1,000 km and a width of ~25 km, that separates the Archean Rae and Slave cratons. The range of metamorphic rocks now exposed at the surface encompasses granulite facies mylonite through to lower‐greenschist facies ultramylonite and cataclasite, providing a potential type example of fault‐zone structure in the middle and lower crust. However, the metamorphic evolution of the units remains poorly quantified, hindering detailed structural and tectonic interpretations. Here, we use phase equilibria modelling and thermobarometry to determine the metamorphic conditions recorded by pelitic, mafic and felsic GSLsz mylonites. Samples from the entire range of granulite–greenschist facies units preserve evidence for nested clockwise pressure–temperature paths that are consistent with a single orogenic cycle. Our findings indicate that the northern Rae margin underwent pervasive crustal thickening with peak pressures in metasedimentary rocks reaching ~1.1 GPa. The crustal thermal gradient at the onset of thickening was ~650°C/GPa, whereas the final stages of equilibrium recorded by fine‐grained matrix minerals in all samples collectively define a metamorphic field gradient of ~1,000°C/GPa. Deformation microstructures are consistent with the main phase of dextral shear having been synchronous with or following peak metamorphism. The history of metamorphism and exhumation of the GSLsz is consistent with the Sibson–Scholz model for shear zones, with a narrowing of the deforming zone and the progressive overprinting of higher‐grade assemblages during exhumation through shallower crustal levels.</jats:p> Article in Journal/Newspaper Great Slave Lake Apollo - University of Cambridge Repository Great Slave Lake ENVELOPE(-114.001,-114.001,61.500,61.500) Sensors 23 24 9724 |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
mylonite phase equilibria modelling shear zone thermometry |
spellingShingle |
mylonite phase equilibria modelling shear zone thermometry Dyck, B Goddard, RM Wallis, D Hansen, LN Martel, E Metamorphic evolution of the Great Slave Lake shear zone |
topic_facet |
mylonite phase equilibria modelling shear zone thermometry |
description |
<jats:title>Abstract</jats:title><jats:p>The Palaeoproterozoic Great Slave Lake shear zone (GSLsz) is a crustal‐scale strike‐slip structure, with a total length of >1,000 km and a width of ~25 km, that separates the Archean Rae and Slave cratons. The range of metamorphic rocks now exposed at the surface encompasses granulite facies mylonite through to lower‐greenschist facies ultramylonite and cataclasite, providing a potential type example of fault‐zone structure in the middle and lower crust. However, the metamorphic evolution of the units remains poorly quantified, hindering detailed structural and tectonic interpretations. Here, we use phase equilibria modelling and thermobarometry to determine the metamorphic conditions recorded by pelitic, mafic and felsic GSLsz mylonites. Samples from the entire range of granulite–greenschist facies units preserve evidence for nested clockwise pressure–temperature paths that are consistent with a single orogenic cycle. Our findings indicate that the northern Rae margin underwent pervasive crustal thickening with peak pressures in metasedimentary rocks reaching ~1.1 GPa. The crustal thermal gradient at the onset of thickening was ~650°C/GPa, whereas the final stages of equilibrium recorded by fine‐grained matrix minerals in all samples collectively define a metamorphic field gradient of ~1,000°C/GPa. Deformation microstructures are consistent with the main phase of dextral shear having been synchronous with or following peak metamorphism. The history of metamorphism and exhumation of the GSLsz is consistent with the Sibson–Scholz model for shear zones, with a narrowing of the deforming zone and the progressive overprinting of higher‐grade assemblages during exhumation through shallower crustal levels.</jats:p> |
format |
Article in Journal/Newspaper |
author |
Dyck, B Goddard, RM Wallis, D Hansen, LN Martel, E |
author_facet |
Dyck, B Goddard, RM Wallis, D Hansen, LN Martel, E |
author_sort |
Dyck, B |
title |
Metamorphic evolution of the Great Slave Lake shear zone |
title_short |
Metamorphic evolution of the Great Slave Lake shear zone |
title_full |
Metamorphic evolution of the Great Slave Lake shear zone |
title_fullStr |
Metamorphic evolution of the Great Slave Lake shear zone |
title_full_unstemmed |
Metamorphic evolution of the Great Slave Lake shear zone |
title_sort |
metamorphic evolution of the great slave lake shear zone |
publisher |
Wiley |
publishDate |
2021 |
url |
https://www.repository.cam.ac.uk/handle/1810/311735 https://doi.org/10.17863/CAM.58825 |
long_lat |
ENVELOPE(-114.001,-114.001,61.500,61.500) |
geographic |
Great Slave Lake |
geographic_facet |
Great Slave Lake |
genre |
Great Slave Lake |
genre_facet |
Great Slave Lake |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/311735 doi:10.17863/CAM.58825 |
op_rights |
All rights reserved |
op_doi |
https://doi.org/10.17863/CAM.58825 |
container_title |
Sensors |
container_volume |
23 |
container_issue |
24 |
container_start_page |
9724 |
_version_ |
1788061522718621696 |