Journal article
Late Jurassic flare‐up of the Coast Mountains arc system, NW Canada, and dynamic linkages across the northern Cordilleran orogen
Tectonics, Vol.36(5), pp.877-901
2017
DOI: 10.1002/2016TC004254
Abstract
Short-lived, high-volume magmatic events or flare-ups in Cordilleran-style accretionary systems are presumably triggered by the rapid underthrusting of melt-fertile lithosphere beneath a continental arc during extreme retroarc shortening. New zircon U-Pb age and trace element geochemical studies of the Coast Mountains batholith were conducted to test this hypothesis and investigate cross-orogen linkages between the Coast Mountains arc system and adjacent retroarc elements of the Canadian Cordillera. Late Jurassic (155–147 Ma) granitoids of the Saint Elias plutonic suite in southwestern Yukon were emplaced during a widespread magmatic event and correspond to an intrusive rate of ~350 km2/Myr, analogous to the scale of 160–150 Ma flare-up activity in the Sierra Nevada batholith. The timing of Late Jurassic high-volume magmatism was coincident with forearc and intraarc deformation events along the length of the Coast Mountains arc from Alaska to British Columbia. Whole-rock and zircon rare earth element geochemical results from the Saint Elias plutonic suite confirm that continental lithosphere was a key source component for Late Jurassic granitoids, which strengthens the implied relationship between high-volume arc magmatism and crustal recycling. Well-documented episodes of late Middle to early Late Jurassic hinterland thrusting and metamorphism in the Intermontane and Omineca belts of the Canadian Cordillera preceded this high-volume event and therefore support the hypothesis that retroarc shortening was dynamically linked to flare-up activity. Late Jurassic magmatism was followed by a 140–125 Ma lull in most of the Coast Mountains batholith, which may be linked to ridge subduction, lithospheric delamination, mantle cooling, or plate reorganization.
Details
- Title: Subtitle
- Late Jurassic flare‐up of the Coast Mountains arc system, NW Canada, and dynamic linkages across the northern Cordilleran orogen
- Creators
- Luke P. Beranek - Memorial University of NewfoundlandWilliam C. McClelland - University of IowaCees R. StaalSteve Israel - Yukon Geological Survey Whitehorse Yukon CanadaSarah M. Gordee - Natural Resources Research Institute
- Resource Type
- Journal article
- Publication Details
- Tectonics, Vol.36(5), pp.877-901
- DOI
- 10.1002/2016TC004254
- ISSN
- 0278-7407
- eISSN
- 1944-9194
- Grant note
- DOI: 10.13039/100000001, name: National Science Foundation, award: EAR‐0948359, EAR‐1049368
- Language
- English
- Date published
- 2017
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229968102771
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