Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska
Abstract Documentation of pressure–temperature ( P–T ) histories across an epidote‐amphibolite facies culmination provides new insight into the tectono‐thermal evolution of the Brooks Range collisional orogen. Thermobarometry reveals that the highest grade rocks formed at peak temperatures of 560–60...
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Online Access: | http://dx.doi.org/10.1046/j.1525-1314.2003.00440.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1525-1314.2003.00440.x https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1525-1314.2003.00440.x |
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crwiley:10.1046/j.1525-1314.2003.00440.x 2024-09-15T18:00:28+00:00 Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska Vogl, J. J. 2003 http://dx.doi.org/10.1046/j.1525-1314.2003.00440.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1525-1314.2003.00440.x https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1525-1314.2003.00440.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Metamorphic Geology volume 21, issue 3, page 269-284 ISSN 0263-4929 1525-1314 journal-article 2003 crwiley https://doi.org/10.1046/j.1525-1314.2003.00440.x 2024-07-25T04:18:49Z Abstract Documentation of pressure–temperature ( P–T ) histories across an epidote‐amphibolite facies culmination provides new insight into the tectono‐thermal evolution of the Brooks Range collisional orogen. Thermobarometry reveals that the highest grade rocks formed at peak temperatures of 560–600 °C and at pressures of 8–9.5 kbar. The thermal culmination coincides with the apex of a structural dome defined by oppositely dipping S2 crenulation cleavages suggesting post‐metamorphic doming. South of the thermal culmination, greenschist facies and lowermost epidote‐amphibolite facies rocks preserve widespread evidence for an early blueschist facies metamorphism. In contrast, no evidence for an early blueschist facies metamorphism was found in similar grade rocks of the northern flank, indicating that the southern flank underwent initial deeper burial during southward underthrusting of the continental margin. Thus, while the dome shows a symmetric distribution of peak temperatures, the P–T paths followed by the two flanks must have varied. This variation suggests that final thermal re‐equilibration to greenschist and epidote–amphibolite facies conditions did not result from a simple process of southward underthrusting followed by thermal re‐equilibration from the bottom upward. The new data are inconsistent with a previous model that invokes such re‐equilibration, along with northward thrusting of epidote–amphibolite facies rocks over lower grade rocks presently on the southern flank of the culmination, to produce an inverted metamorphic field gradient. Instead, it is suggested that following blueschist facies metamorphism, rocks of the southern and northern flanks were juxtaposed, during which time the more deeply buried south flank was partially emplaced above rocks to the north, where they escaped Albian epidote–amphibolite facies overprinting. Porphyroblast growth, which post‐dates the main fabric on the north flank of the culmination may be the result of Albian thermal re‐equilibration following this ... Article in Journal/Newspaper Brooks Range Alaska Wiley Online Library Journal of Metamorphic Geology 21 3 269 284 |
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Wiley Online Library |
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English |
description |
Abstract Documentation of pressure–temperature ( P–T ) histories across an epidote‐amphibolite facies culmination provides new insight into the tectono‐thermal evolution of the Brooks Range collisional orogen. Thermobarometry reveals that the highest grade rocks formed at peak temperatures of 560–600 °C and at pressures of 8–9.5 kbar. The thermal culmination coincides with the apex of a structural dome defined by oppositely dipping S2 crenulation cleavages suggesting post‐metamorphic doming. South of the thermal culmination, greenschist facies and lowermost epidote‐amphibolite facies rocks preserve widespread evidence for an early blueschist facies metamorphism. In contrast, no evidence for an early blueschist facies metamorphism was found in similar grade rocks of the northern flank, indicating that the southern flank underwent initial deeper burial during southward underthrusting of the continental margin. Thus, while the dome shows a symmetric distribution of peak temperatures, the P–T paths followed by the two flanks must have varied. This variation suggests that final thermal re‐equilibration to greenschist and epidote–amphibolite facies conditions did not result from a simple process of southward underthrusting followed by thermal re‐equilibration from the bottom upward. The new data are inconsistent with a previous model that invokes such re‐equilibration, along with northward thrusting of epidote–amphibolite facies rocks over lower grade rocks presently on the southern flank of the culmination, to produce an inverted metamorphic field gradient. Instead, it is suggested that following blueschist facies metamorphism, rocks of the southern and northern flanks were juxtaposed, during which time the more deeply buried south flank was partially emplaced above rocks to the north, where they escaped Albian epidote–amphibolite facies overprinting. Porphyroblast growth, which post‐dates the main fabric on the north flank of the culmination may be the result of Albian thermal re‐equilibration following this ... |
format |
Article in Journal/Newspaper |
author |
Vogl, J. J. |
spellingShingle |
Vogl, J. J. Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska |
author_facet |
Vogl, J. J. |
author_sort |
Vogl, J. J. |
title |
Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska |
title_short |
Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska |
title_full |
Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska |
title_fullStr |
Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska |
title_full_unstemmed |
Thermal‐baric structure and P–T history of the Brooks Range metamorphic core, Alaska |
title_sort |
thermal‐baric structure and p–t history of the brooks range metamorphic core, alaska |
publisher |
Wiley |
publishDate |
2003 |
url |
http://dx.doi.org/10.1046/j.1525-1314.2003.00440.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1525-1314.2003.00440.x https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1525-1314.2003.00440.x |
genre |
Brooks Range Alaska |
genre_facet |
Brooks Range Alaska |
op_source |
Journal of Metamorphic Geology volume 21, issue 3, page 269-284 ISSN 0263-4929 1525-1314 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1046/j.1525-1314.2003.00440.x |
container_title |
Journal of Metamorphic Geology |
container_volume |
21 |
container_issue |
3 |
container_start_page |
269 |
op_container_end_page |
284 |
_version_ |
1810437624605704192 |