| Titre | Preliminary observations on the style and timing of deformation along the Bathurst Fault, western Nunavut |
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| Auteur | Ma, S; Godin, L; Kellett, D A |
| Source | Program with abstracts: Muskoka 2016, 36th Canadian Tectonics Group Workshop; 2016 p. 31  Accès ouvert |
| Liens | Online - En ligne (complete volume - volume complet, PDF, 1.17 MB)
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| Année | 2016 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190447 |
| Réunion | 36th Canadian Tectonics Group Workshop; Bracebridge, ON; CA; Octobre 21-23, 2016 |
| Document | livre |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Nunavut |
| Sujets | Faille de Bathurst ; géochronologie; tectonique; Sciences et technologie; Nature et environnement |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Chantrey-Thelon de la province de Rae |
| Diffusé | 2016 10 31 |
| Résumé | (disponible en anglais seulement)
The Bathurst Fault is a NNW-trending crustal-scale structure that transects through the eastern Slave craton and left-laterally displaces the Thelon tectonic
zone by up to 140 km. Though there is no geochronological constraint on the timing of fault motion, early studies suggest that the fault initiated in response to Slave-Rae convergence and then reactivated in the Paleo- to Meso-proterozoic. The
Bathurst Fault is a prospective structure associated with known uranium occurrences in the Proterozoic Kilohigok and Thelon basins. The close relationship between fault zones, which often behave as pathways and depositional sites for U-bearing
fluids, and Proterozoic basins are well recognized targets of exploration in Canada. This M.Sc. study aims to constrain the style and timing of deformation along the Bathurst Fault zone to construct a temperature-deformation history of fault
reactivation. The temporal relationship between the Bathurst Fault and the Slave-Rae collision, Thelon orogen, and nearby uranium mineralization in Proterozoic basins will be established with age-dating (40Ar/39Ar thermochronology and U-Th/Pb
geochronology) paired with microstructural observations and quartz petrofabrics. In July 2016, field observations and samples from two transects across the fault at detailed sites were collected. The Bathurst Fault is manifested as a zone of high
strain rocks in the central transect and as discrete brittle lineaments in the northern transect. Field observations in the central transect reveal a suite of high metamorphic-grade and variably strained granitoid rocks in the fault zone and east
within the Thelon tectonic zone. These are juxtaposed against less resistant metasedimentary and metavolcanic rocks of the Slave craton west of the fault. Deformation fabrics (e.g. mylonite and L-tectonite) are parallel to the Bathurst trend and
strain is localized within mica- and amphibole-rich horizons of quartz syenite to monzonite rocks. Mineral lineations, defined by oriented hornblende and flattened alkali-feldspar grains, in the fault zone are steeply plunging and where shear sense
indicators are present, show top-to-the NW shear. Preliminary petrographic observations indicate pervasive intracrystalline deformation textures in abundant feldspar and quartz grains. In feldspars, intracrystalline microstructures suggest a range of
deformation mechanisms active from low temperature (e.g. microfaulting, bent twins) to medium-high temperature (e.g. subgrain development). In the northern transect, quartz arenite samples from the base of the Kilohigok Basin will be utilized to test
for the presence of a strain gradient adjacent to this brittle section of the Bathurst Fault. Overall field relationships suggest that early ductile mylonitic fabrics, likely Thelon-related, are overprinted by Bathurst-related ductile shearing
evolving to late brittle fracturing. Upcoming work will include U-Th/Pb dating of monazite to constrain the early ductile phase of fault motion. 40Ar/39Ar dating of hornblende and muscovite will provide a cooling history that will be correlated with
deformation temperature as revealed by quartz petrofabrics and feldspar microtextures. |
| GEOSCAN ID | 321722 |
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