Grant: Alliance Grants

The Precambrian shield of Canada consists of several large Archean (> 2.5 billion year) blocks that collided during a major period of mountain building, ca. 2.0-1.8 billion years ago to form earth's first supercontinent, Nuna. While progress has been made on understanding how these blocks came together, significant uncertainty remains, especially in the western shield where the relative effects of superposed tectonism related to older (2.5-2.3 billion year) Arrowsmith orogenesis (mountain building) and younger (2.01-1.91 billion year) Thelon-Taltson orogenesis are difficult to distinguish. Within this context, faults have a profound influence on the development of mountain belts. While they typically play a role, early on (i.e., collisional stages) they are commonly also re-activated during the later stages. Faults are also major conduits for hot, deep crustal fluids that carry critical elements, including gold. The proposed research deals with the Tazin River shear zone, a major fault zone in the southern Taltson orogen, Northwest Territories. While this fault/shear zone appears to have a long-lived history, the nature and timing of fault movement remains uncertain. It is also unclear if this fault zone represents an early boundary between colliding blocks, or merely a locus of younger differential movement and uplift. Through mapping and cutting-edge techniques in geochronology this research will help to determine the history of this fault zone; and in particular, figure out if it was active (i.e., a fundamental boundary) during early stages of orogenesis, and if and how it was reactivated during later stages. It will also study the timing/controls of fault-related mineral occurrences, including gold. This knowledge of fault history within a regional geologic framework, coupled with mineralogical controls, will provide up-dated knowledge on mineral prospectivity within a poorly known region of the shield. This research thus promises to help a variety of stakeholders, including federal, territorial and Indigenous governments/organizations, to make informed decisions on mineral resource potential in this region, which could impact future prosperity.