Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides
The thrust-related Imbricate Zone and thesinistral strike-slip Storstrømmen Shear Zone (SSZ)are two major orogen-parallel ductile shear zones thatmark the western limit of intense Caledoniandeformation in northeast Greenland and transect theorogenic hinterland, respectively. Detailed micro-structura...
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ftunivportsmpubl:oai:researchportal.port.ac.uk:publications/3b0e36a3-ab13-49a0-901d-434491444297 2023-05-15T16:02:38+02:00 Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides Smith, S. Strachan, Rob Holdsworth, R. 2007 https://doi.org/10.1029/2006TC001952 https://researchportal.port.ac.uk/portal/en/publications/microstructural-evolution-within-a-partitioned-midcrustaltranspression-zone-northeast-greenland-caledonides(3b0e36a3-ab13-49a0-901d-434491444297).html eng eng info:eu-repo/semantics/restrictedAccess Smith , S , Strachan , R & Holdsworth , R 2007 , ' Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides ' Tectonics , vol 26 , no. TC4003 , pp. 1-20 . DOI:10.1029/2006TC001952 /dk/atira/pure/core/subjects/earthsci Earth Sciences article 2007 ftunivportsmpubl https://doi.org/10.1029/2006TC001952 2017-09-28T19:30:48Z The thrust-related Imbricate Zone and thesinistral strike-slip Storstrømmen Shear Zone (SSZ)are two major orogen-parallel ductile shear zones thatmark the western limit of intense Caledoniandeformation in northeast Greenland and transect theorogenic hinterland, respectively. Detailed micro-structural analysis of associated mylonitic faultrocks from Dronning Louise Land and Hertugen afOrléans Land has been carried out to provide insightsinto the evolution of these structures and to constrainthe relative timing of movement. Amphibolite-faciesmylonites were developed across the entire ca. 8-km-wide SSZ and are currently exposed across an area ca.3–4 km wide within the center of the shear zone.In contrast, retrograde greenschist-facies mylonites areconcentrated within a ca. 2- to 4-km-wide belt alongthe western margin of the shear zone. This meta-morphic pattern is interpreted to reflect progressivelocalization of strain associated with exhumation andsyntectonic cooling. The ca. 15-km-wide ImbricateZone consists of numerous east-dipping ductile thrustsheets. At low structural levels, mylonitic fabricsindicate that thrust-related deformation occurred atmiddle-greenschist facies. Toward higher levels, how-ever, microstructures suggest that the metamorphicgrade progressively increases. We propose that ductilethrusting across the Imbricate Zone was synchronouswith uplift and exhumation of the orogenic hinterlandand SSZ, accounting for the observed metamorphicvariations. This implies that both structures wereactive broadly contemporaneously during regionalpartitioned transpression, an inference supported byscattered 40Ar/39Ar and recent U-Pb zircon ages. Themicrostructural observations therefore support modelsthat involve sinistrally oblique Silurian-Devonian col-lision between Laurentia and Baltica. Article in Journal/Newspaper Dronning Louise land Greenland University of Portsmouth: Portsmouth Research Portal Greenland Dronning Louise Land ENVELOPE(-24.250,-24.250,76.500,76.500) Tectonics 26 4 n/a n/a |
institution |
Open Polar |
collection |
University of Portsmouth: Portsmouth Research Portal |
op_collection_id |
ftunivportsmpubl |
language |
English |
topic |
/dk/atira/pure/core/subjects/earthsci Earth Sciences |
spellingShingle |
/dk/atira/pure/core/subjects/earthsci Earth Sciences Smith, S. Strachan, Rob Holdsworth, R. Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides |
topic_facet |
/dk/atira/pure/core/subjects/earthsci Earth Sciences |
description |
The thrust-related Imbricate Zone and thesinistral strike-slip Storstrømmen Shear Zone (SSZ)are two major orogen-parallel ductile shear zones thatmark the western limit of intense Caledoniandeformation in northeast Greenland and transect theorogenic hinterland, respectively. Detailed micro-structural analysis of associated mylonitic faultrocks from Dronning Louise Land and Hertugen afOrléans Land has been carried out to provide insightsinto the evolution of these structures and to constrainthe relative timing of movement. Amphibolite-faciesmylonites were developed across the entire ca. 8-km-wide SSZ and are currently exposed across an area ca.3–4 km wide within the center of the shear zone.In contrast, retrograde greenschist-facies mylonites areconcentrated within a ca. 2- to 4-km-wide belt alongthe western margin of the shear zone. This meta-morphic pattern is interpreted to reflect progressivelocalization of strain associated with exhumation andsyntectonic cooling. The ca. 15-km-wide ImbricateZone consists of numerous east-dipping ductile thrustsheets. At low structural levels, mylonitic fabricsindicate that thrust-related deformation occurred atmiddle-greenschist facies. Toward higher levels, how-ever, microstructures suggest that the metamorphicgrade progressively increases. We propose that ductilethrusting across the Imbricate Zone was synchronouswith uplift and exhumation of the orogenic hinterlandand SSZ, accounting for the observed metamorphicvariations. This implies that both structures wereactive broadly contemporaneously during regionalpartitioned transpression, an inference supported byscattered 40Ar/39Ar and recent U-Pb zircon ages. Themicrostructural observations therefore support modelsthat involve sinistrally oblique Silurian-Devonian col-lision between Laurentia and Baltica. |
format |
Article in Journal/Newspaper |
author |
Smith, S. Strachan, Rob Holdsworth, R. |
author_facet |
Smith, S. Strachan, Rob Holdsworth, R. |
author_sort |
Smith, S. |
title |
Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides |
title_short |
Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides |
title_full |
Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides |
title_fullStr |
Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides |
title_full_unstemmed |
Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides |
title_sort |
microstructural evolution within a partitioned midcrustaltranspression zone, northeast greenland caledonides |
publishDate |
2007 |
url |
https://doi.org/10.1029/2006TC001952 https://researchportal.port.ac.uk/portal/en/publications/microstructural-evolution-within-a-partitioned-midcrustaltranspression-zone-northeast-greenland-caledonides(3b0e36a3-ab13-49a0-901d-434491444297).html |
long_lat |
ENVELOPE(-24.250,-24.250,76.500,76.500) |
geographic |
Greenland Dronning Louise Land |
geographic_facet |
Greenland Dronning Louise Land |
genre |
Dronning Louise land Greenland |
genre_facet |
Dronning Louise land Greenland |
op_source |
Smith , S , Strachan , R & Holdsworth , R 2007 , ' Microstructural evolution within a partitioned midcrustaltranspression zone, northeast Greenland Caledonides ' Tectonics , vol 26 , no. TC4003 , pp. 1-20 . DOI:10.1029/2006TC001952 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1029/2006TC001952 |
container_title |
Tectonics |
container_volume |
26 |
container_issue |
4 |
container_start_page |
n/a |
op_container_end_page |
n/a |
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1766398290047270912 |