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Strain partitioning in accretionary orogens, and its effects on orogenic collapse: Insights from western North America

2013; Geological Society of America; Volume: 125; Issue: 7-8 Linguagem: Inglês

10.1130/b30777.1

1943-2674

Steve Israel, L. A. Kennedy, Richard M. Friedman,

High-pressure geophysics and materials

Research Article| July 01, 2013 Strain partitioning in accretionary orogens, and its effects on orogenic collapse: Insights from western North America Steve A. Israel; Steve A. Israel † 1Yukon Geological Survey, 2099 2nd Avenue, Whitehorse, Yukon Y1A 1B5, Canada †E-mail: Steve.Israel@gov.yk.ca. Search for other works by this author on: GSW Google Scholar Lori A. Kennedy; Lori A. Kennedy 2Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada Search for other works by this author on: GSW Google Scholar Richard M. Friedman Richard M. Friedman 2Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Steve A. Israel † 1Yukon Geological Survey, 2099 2nd Avenue, Whitehorse, Yukon Y1A 1B5, Canada Lori A. Kennedy 2Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada Richard M. Friedman 2Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada †E-mail: Steve.Israel@gov.yk.ca. Publisher: Geological Society of America Received: 14 Aug 2012 Revision Received: 23 Apr 2013 Accepted: 24 Apr 2013 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2013 Geological Society of America GSA Bulletin (2013) 125 (7-8): 1260–1281. https://doi.org/10.1130/B30777.1 Article history Received: 14 Aug 2012 Revision Received: 23 Apr 2013 Accepted: 24 Apr 2013 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Steve A. Israel, Lori A. Kennedy, Richard M. Friedman; Strain partitioning in accretionary orogens, and its effects on orogenic collapse: Insights from western North America. GSA Bulletin 2013;; 125 (7-8): 1260–1281. doi: https://doi.org/10.1130/B30777.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Changes in relative plate motions during the construction of accretionary orogens generally result in varying structural styles along the length of the orogen. These disparate structural styles can be interpreted as having been formed by different tectonic regimes along the orogenic axis that formed at the same time. If the orogen is considered at the large scale, the differences in the way in which the crust responds during accretion can be explained by large-scale strain partitioning within the same overall tectonic environment.The westernmost Canadian Cordillera records the transition from Late Cretaceous dextral strike-slip faulting to near-orthogonal compression along the orogenic axis. We postulate that the transition between strike-slip–dominated to compression-dominated tectonics represents a Late Cretaceous partitioning of strain that resulted in a significant difference in crustal rheology along strike of the orogeny. This had a dramatic effect on subsequent Tertiary orogen-scale extension. We propose that plate readjustments in the Tertiary led to orogen-perpendicular collapse in portions of the orogen, facilitated by decoupling between the middle and lower crusts along thermally weakened layers. In contrast, localized, orogen-parallel extension occurred in other portions of the orogen, along kinematically linked, large dextral strike-slip faults where the upper crust remained coupled to the middle and lower crust.New data indicate that partitioning of strain occurs across very large regions within any orogenic system, and that the way in which strain is partitioned can lead to dramatic differences in future orogenic processes. It becomes apparent from these data that orogens must be examined as a whole and that differing structural styles of similar ages are likely responses to the same overall tectonic regime. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.