Lithostratigraphic and structural controls of uranium mineralization in the Kiggavik East Zone, Centre Zone, and Main Zone deposits, Thelon Basin, Nunavut

• Main Author: Johnstone, Dillon Daniel
• Other Authors: Bethune, Kathryn, Chi, Guoxiang, Raharimahefa, Tsilavo, Ansdell, Kevin
• Format: Thesis
• Language: English
• Published: Faculty of Graduate Studies and Research, University of Regina 2017
• Subjects: Nunavut; Snow Island; Ketyet River
• Online Access: http://hdl.handle.net/10294/8419; https://ourspace.uregina.ca/bitstream/handle/10294/8419/Johnstone_Dillon_MSC_GEOL_Spring2018.pdf

A Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Geology, University of Regina. x, 182 p. The Kiggavik uranium deposits are located in the north-central Rae Subprovince of the Western Churchill Province and are hosted in highly deformed Archean and Paleoproterozoic basement rocks proximal to, and underlying the Thelon Basin. This field-based study documents the lithostratigraphic and structural character of Kiggavik’s basement rocks and their controls on the uranium deposits. Field investigation, coupled with structural analysis, geochemistry and geochronology indicates that the basement rocks comprise two main tectonostratigraphic packages: a structurally ‘lower-package’ comprising ~2.71 Ga Pipedream assemblage metagreywacke and a structurally ‘upper-package’ consisting of multiple intervals of ~2.6 Ga Snow Island Suite felsic epiclastic and metarhyolite intercalated with less than 2.3 Ga quartzite of the Ketyet River group. Of particular significance are the epiclastic rocks, which, based on their textural variability, felsic composition, negative europium anomaly and association with metarhyolite, are correlated with previously identified epiclastic volcanic rocks in the western part of the area, rendering this the most spatially extensive rock unit at Kiggavik. Further, field investigation, coupled with structural analysis, confirms that all units form a homoclinal sequence that dips gently NNW in the eastern map area (Domain 1) and ENE in the western map area (Domain 2). Based on regional stratigraphic relationships, down-section profiles in both domains contain multiple younging direction reversals. This, coupled with strongly transposed bedding, ubiquitous foliation and highly strained contacts, plus the direct observation of isoclinal, recumbent folds in both outcrop and drill core, indicates that these repetitions are tectonic. In addition, across both domains, all units carry a well-developed ...