The Wernecke igneous clasts in Yukon, Canada: evidence for a Paleoproterozoic volcanic arc terrane at 1.7 Ga and its obduction onto ancestral North America

Date created: 
2011-12-15
Identifier: 
etd6981
Keywords: 
Geochemistry
Metasomatism
Tectonic environments
Samarium neodymium isotopes
Proterozoic
Yukon
Abstract: 

All observed Wernecke igneous clasts (WIC) occur within the 1.60 Ga Wernecke Breccias of Yukon, Canada. The clasts range up to 5.4 million m3 in volume, and comprise the 1.71 Ga Bonnet Plume River Intrusions (BPRI), the Slab volcanics, the Devil volcanics, and the Blackstone River megaclast. The WIC were not emplaced through the <1.64 Ga Wernecke Supergroup (WSG). The BPRI and Devil volcanics have a geochemical affinity with volcanic arcs. The Slab volcanics are more alkaline, like mantle plume or slab-window derived volcanoes. Sm-Nd isotopes indicate that magmas of the BPRI and Devil volcanics assimilated older basement rock. The WIC originated in a terrane that was obducted onto the WSG. Hydrothermal fluids brecciated these units, forming the Wernecke Breccias. WICs derived from the terrane foundered into these breccias to the level of the WSG and were metasomatized. The obducted terrane eroded entirely prior to deposition of the Pinguicula Group.

Document type: 
Thesis
Rights: 
Copyright remains with the author. The author granted permission for the file to be printed and for the text to be copied and pasted.
File(s): 
Supervisor(s): 
Derek Thorkelson
Department: 
Science: Department of Earth Sciences
Thesis type: 
(Thesis) M.Sc.
Statistics: