The Contact uranium prospect, Kiggavik project, Nunavut (Canada): Tectonic history, structural constraints and timing of mineralization

• Published in: Ore Geology Reviews
• Main Authors: Grare, Alexis, Benedicto, Antonio, Lacombe, Olivier, Trave, Anna, Ledru, Patrick, Blain, Mario, Robbins, John
• Other Authors: Déformations, sismotectonique, imagerie, relief (DéSIR), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Uranium deposit; alteration; structural control; fracture; Thelon Basin; Kiggavik; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Alf; Canada; Nunavut; The Baker; Wharton; Baker Lake
• Online Access: https://hal.sorbonne-universite.fr/hal-01675254; https://hal.sorbonne-universite.fr/hal-01675254/document; https://hal.sorbonne-universite.fr/hal-01675254/file/Grare%20et%20al.%20%282017%29%20The%20Contact%20prospect%20-%20Vers%20comb%20manuscr3.pdf; https://doi.org/10.1016/j.oregeorev.2017.12.015

International audience Uranium mineralization in the Kiggavik area, on the eastern border of the Thelon basin (Nunavut, Canada), hosts significant uranium resources within the basement and its understanding is critical to comprehending the genesis of unconformity-related deposits' structural controls and therefore exploration of these types of deposits in this prospective district. This article deciphers the complex multiphase fracture network associated with uranium mineralization of the most recently discovered, basement-hosted prospect in the Kiggavik area, named Contact. The Contact prospect is located along the Andrew Lake Fault (ALF), a major NE-SW fault corridor in the area. This study combines field work, drillcore logging, sampling, and macro-to micro-petro-structural analyses. Key results from this study highlight that the NE-trending ALF, along with the ENE-trending Thelon (TF) and Judge Sissons (JSF) faults, formed early during intracratonic rifting and deposition of the Baker Lake and Wharton groups (ca. 1850–1750 Ma) in response to the Thelon and Trans-Hudsonian orogeny. The ALF was affected by a strong silicification-brecciation event that likely developed at ca. 1750 Ma, and partitioned later deformation and fluid circulation. In the Contact prospect, the ALF was reactivated multiple times and mineralized in three stages with distinctive secondary fracture patterns, alteration, and mineralization types. Ten fracture stages have been identified at the Contact prospect, f1 to f10. The first stage of mineralization, coeval with f5, is related to fluids of unconstrained origin that circulated through E-W faults in the area that locally reactivated quartz veins of the brecciation event at the intersection with the ALF. Mineralization at this stage is polymetallic and associated with weak clay alteration. The second stage of uranium mineralization occurred coeval with transtensional reactivation of the NE-SW trending ALF (f6c) and in relation to circulation of oxidizing basinal brines within the ...