A coming together: The juxtaposition of the Rae and Hearne cratons along the Virgin River shear zone (Snowbird tectonic zone), Saskatchewan, Canada, and the implications for proto-Laurentia
type: CreativeWork
description: The Snowbird tectonic zone of western Laurentia remains an enigmatic feature; some researchers have suggested that it represents a Paleoproterozoic suture, whereas others have proposed that it represents a reactivated Archean intracratonic fault zone. The Virgin River shear zone is the most southwesterly exposure of the Snowbird tectonic zone, along which rocks of the southern Rae and southern Hearne provinces meet. The Rae craton is the hanging wall to the northwest-dipping structure. Rocks of the southwest Rae are an extension of the Taltson basement complex and the intrusive Taltson magmatic zone. The Taltson basement complex contains ca. 2460 Ma diorites and granites, and granulite-facies metasedimentary rocks, the Careen Lake group. The ca. 2110 Ma Clearwater anorthosite complex and a swarm of mafic dykes intruded the Taltson basement complex near the Virgin River shear zone. These rocks were intruded by continental volcanic arc plutons between 1.99 and 1.97 Ga, indicating a convergent tectonic setting along the southwestern margin of the Rae. The metamorphic culmination of the Taltson orogeny developed at 1.94-1.93 Ga, independently of the Thelon orogeny, which culminated some 10-20 million years earlier. The footwall of the Virgin River shear zone comprises rocks of the southern Hearne Province, which is dominated by a felsic orthogneiss complex that contains ca. 2809 Ma tonalites, ca. 2664 Ma leucotonalites, ca. 2554 Ma granodiorites and quartz diorites, and ca. 2.63-2.60 Ga porphyritic granites. These rocks are unconformably overlain by the <2600 Ma Black Birch Lake assemblage, a quartzite- and amphibolitebearing supracrustal succession that may be correlative with the lower part of the Wollaston Supergroup. Although all of these rocks contain a fabric that predates the Virgin River shear zone, the bulk of the deformation and the metamorphic assemblages derive from the Trans-Hudson orogeny. The rocks of the felsic orthogneiss complex, which have dominantly …
abstract: The Snowbird tectonic zone of western Laurentia remains an enigmatic feature; some researchers have suggested that it represents a Paleoproterozoic suture, whereas others have proposed that it represents a reactivated Archean intracratonic fault zone. The Virgin River shear zone is the most southwesterly exposure of the Snowbird tectonic zone, along which rocks of the southern Rae and southern Hearne provinces meet. The Rae craton is the hanging wall to the northwest-dipping structure. Rocks of the southwest Rae are an extension of the Taltson basement complex and the intrusive Taltson magmatic zone. The Taltson basement complex contains ca. 2460 Ma diorites and granites, and granulite-facies metasedimentary rocks, the Careen Lake group. The ca. 2110 Ma Clearwater anorthosite complex and a swarm of mafic dykes intruded the Taltson basement complex near the Virgin River shear zone. These rocks were intruded by continental volcanic arc plutons between 1.99 and 1.97 Ga, indicating a convergent tectonic setting along the southwestern margin of the Rae. The metamorphic culmination of the Taltson orogeny developed at 1.94-1.93 Ga, independently of the Thelon orogeny, which culminated some 10-20 million years earlier. The footwall of the Virgin River shear zone comprises rocks of the southern Hearne Province, which is dominated by a felsic orthogneiss complex that contains ca. 2809 Ma tonalites, ca. 2664 Ma leucotonalites, ca. 2554 Ma granodiorites and quartz diorites, and ca. 2.63-2.60 Ga porphyritic granites. These rocks are unconformably overlain by the <2600 Ma Black Birch Lake assemblage, a quartzite- and amphibolitebearing supracrustal succession that may be correlative with the lower part of the Wollaston Supergroup. Although all of these rocks contain a fabric that predates the Virgin River shear zone, the bulk of the deformation and the metamorphic assemblages derive from the Trans-Hudson orogeny. The rocks of the felsic orthogneiss complex, which have dominantly …
author: Card, Colin Dale
language: en
date published: 2016-07
date modified: 2026-07-24T04:03:32Z
provider: University of Regina
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Faculty of Graduate Studies and Research, University of Regina

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10294/7616

PropertyValue
property ID: DOI
value: 10.82465/4137