Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence
A regional system of S-dipping faults is exposed in the Florence and Fall Creeks area of the south-central Brooks Range. This fault system has previously been mapped as the ‘root zone’ of a N-vergent fold-and-thrust belt of Jurassic-Cretaceous age, although individual faults juxtapose lower grade on...
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1994
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ftcaltechauth:oai:authors.library.caltech.edu:85350 2023-05-15T15:46:57+02:00 Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence Law, Richard D. Miller, Elizabeth L. Little, Timothy A. Lee, Jeffrey 1994-07 https://authors.library.caltech.edu/85350/ https://resolver.caltech.edu/CaltechAUTHORS:20180316-154525787 unknown Elsevier Law, Richard D. and Miller, Elizabeth L. and Little, Timothy A. and Lee, Jeffrey (1994) Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence. Journal of Structural Geology, 16 (7). pp. 919-940. ISSN 0191-8141. doi:10.1016/0191-8141(94)90076-0. https://resolver.caltech.edu/CaltechAUTHORS:20180316-154525787 <https://resolver.caltech.edu/CaltechAUTHORS:20180316-154525787> Article PeerReviewed 1994 ftcaltechauth https://doi.org/10.1016/0191-8141(94)90076-0 2021-11-18T18:45:18Z A regional system of S-dipping faults is exposed in the Florence and Fall Creeks area of the south-central Brooks Range. This fault system has previously been mapped as the ‘root zone’ of a N-vergent fold-and-thrust belt of Jurassic-Cretaceous age, although individual faults juxtapose lower grade on higher grade metamorphic rocks suggesting apparent extensional geometries. The structurally highest of these faults places rocks of the oceanic Paleozoic-Mesozoic Angayucham terrane, together with unconformably overlying Cretaceous clastic rocks, on Devonian metagreywacke and phyllite. This metagreywacke-phyllite (MP) unit in turn structurally overlies Devonian (?) and older basement rocks of the Brooks Range Schist Belt along a S-dipping structural contact previously mapped as the Florence Creek fault. The Schist Belt and MP units are both characterized by a regionally developed, S-dipping greenschist facies foliation that displays a pronounced N-S-trending, down-dip elongation lineation which earlier workers regarded as being associated with N-vergent thrusting. While only one foliation (S_d) is recognized in the MP unit, in the underlying Schist Belt this foliation (S_2) overprints an earlier blueschist facies mineral assemblage and associated foliation (S_1). Article in Journal/Newspaper Brooks Range Alaska Caltech Authors (California Institute of Technology) Journal of Structural Geology 16 7 919 940 |
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Caltech Authors (California Institute of Technology) |
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description |
A regional system of S-dipping faults is exposed in the Florence and Fall Creeks area of the south-central Brooks Range. This fault system has previously been mapped as the ‘root zone’ of a N-vergent fold-and-thrust belt of Jurassic-Cretaceous age, although individual faults juxtapose lower grade on higher grade metamorphic rocks suggesting apparent extensional geometries. The structurally highest of these faults places rocks of the oceanic Paleozoic-Mesozoic Angayucham terrane, together with unconformably overlying Cretaceous clastic rocks, on Devonian metagreywacke and phyllite. This metagreywacke-phyllite (MP) unit in turn structurally overlies Devonian (?) and older basement rocks of the Brooks Range Schist Belt along a S-dipping structural contact previously mapped as the Florence Creek fault. The Schist Belt and MP units are both characterized by a regionally developed, S-dipping greenschist facies foliation that displays a pronounced N-S-trending, down-dip elongation lineation which earlier workers regarded as being associated with N-vergent thrusting. While only one foliation (S_d) is recognized in the MP unit, in the underlying Schist Belt this foliation (S_2) overprints an earlier blueschist facies mineral assemblage and associated foliation (S_1). |
format |
Article in Journal/Newspaper |
author |
Law, Richard D. Miller, Elizabeth L. Little, Timothy A. Lee, Jeffrey |
spellingShingle |
Law, Richard D. Miller, Elizabeth L. Little, Timothy A. Lee, Jeffrey Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence |
author_facet |
Law, Richard D. Miller, Elizabeth L. Little, Timothy A. Lee, Jeffrey |
author_sort |
Law, Richard D. |
title |
Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence |
title_short |
Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence |
title_full |
Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence |
title_fullStr |
Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence |
title_full_unstemmed |
Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence |
title_sort |
extensional origin of ductile fabrics in the schist belt, central brooks range, alaska—ii. microstructural and petrofabric evidence |
publisher |
Elsevier |
publishDate |
1994 |
url |
https://authors.library.caltech.edu/85350/ https://resolver.caltech.edu/CaltechAUTHORS:20180316-154525787 |
genre |
Brooks Range Alaska |
genre_facet |
Brooks Range Alaska |
op_relation |
Law, Richard D. and Miller, Elizabeth L. and Little, Timothy A. and Lee, Jeffrey (1994) Extensional origin of ductile fabrics in the Schist Belt, Central Brooks Range, Alaska—II. Microstructural and petrofabric evidence. Journal of Structural Geology, 16 (7). pp. 919-940. ISSN 0191-8141. doi:10.1016/0191-8141(94)90076-0. https://resolver.caltech.edu/CaltechAUTHORS:20180316-154525787 <https://resolver.caltech.edu/CaltechAUTHORS:20180316-154525787> |
op_doi |
https://doi.org/10.1016/0191-8141(94)90076-0 |
container_title |
Journal of Structural Geology |
container_volume |
16 |
container_issue |
7 |
container_start_page |
919 |
op_container_end_page |
940 |
_version_ |
1766381755925790720 |