Structural Style and Regional Comparison of the Paleoproterozoic Ketyet River Group in the Region North-Northwest of Baker Lake, Nunavut

• Main Author: McEwan, Brian John
• Other Authors: Bethune, Kathryn M., Chi, Guoxiang, Ashton, Kenneth E., Lafrance, Bruno
• Format: Thesis
• Language: English
• Published: Faculty of Graduate Studies and Research, University of Regina 2012
• Subjects: Geology; Stratigraphic > Proterozoic; Geology > Nunavut > Ketyet River Region; Geology > Nunavut > Baker Lake Region; Nunavut; Ketyet River; Bar Lake; Five Mile Lake; Baker Lake
• Online Access: http://hdl.handle.net/10294/3815; http://ourspace.uregina.ca/bitstream/handle/10294/3815/McEwan_Brian_200254478_MSC_GEOL_Spring2013l.pdf

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. ix, 160 l. Archean to Paleoproterozoic rocks of the Rae Craton, Western Churchill Province, have been affected by polyphase deformation and metamorphism causing structural complexity and confusion regarding the age and affiliation of rock units. This study improves the stratigraphic and structural understanding of the Paleoproterozoic Ketyet River group and immediately subjacent Neoarchean rocks through detailed mapping of four areas north and west of Baker Lake: “Nipterk Lake”, “Ukalik Lake”, “Bar Lake” and Kiggavik, north of the uranium deposits. This improves knowledge of the basement rocks marginal to the late Paleoproterozoic Thelon Basin for unconformity-related uranium exploration. In 2010 and 2011, detailed mapping in the first three areas revealed that the Ketyet River group comprises thin metaconglomerate gradationally overlain by orthoquartzite and grey pelitic schist. At Bar Lake, sills of metagabbro within the latter may be equivalent to the Five Mile Lake basalts, substantiating correlation with the Amer Group. The metaconglomerate and orthoquartzite unconformably overlie 2.6 Ga quartz-K-feldspar porphyritic schist (QFP schist) and parts of the Woodburn Lake group ranging from feldspathic metagreywacke to komatiite. Where the metaconglomerate is absent, the base of the orthoquartzite contains “quartz eyes” resembling those of the QFP schist. Cross-beds at the base and top of the orthoquartzite respectively face away from the QFP schist and toward the pelitic schist, providing control on the younging direction. The quartzite-pelitic schist contact is gradational; approaching the contact, decimetre-scale granule- to pebble-metaconglomerate and centimetre-scale pelitic schist interbeds are common, whereas above the contact, the pelitic schist contains graded granule metaconglomerate interbeds. Five ductile deformational ...