Structural Controls on the Mary River Iron Ore Deposit, North Baffin Island, Nunavut

Saumur, B.M. et Johnston, S. T. (2024). « Structural Controls on the Mary River Iron Ore Deposit, North Baffin Island, Nunavut », dans GAC-MAC-PEG 2024 Brandon Meeting: Abstracts, Volume 47 (GAC-MAC-PEG, Brandon, 19-24 mai 2024), sous la dir. de Alexander, P.. p. 115.

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Résumé

The Mary River Fe-ore deposits of northern Baffin Island are hosted in the ArcheanMary River Group; Deposit 1 is the site of Canada’s northernmost active mine.Greenstone belts of the Mary River Group form discontinuous, 1–10 km scale, vari-ably deformed and metamorphosed panels within orthogneiss and granitoid rocksof the Rae Craton. Despite evidence for Archean deformation, two main tectonicevents, including the Paleoproterozoic collisional Trans-Hudson orogeny and theMesoproterozoic extensional events forming the Bylot basins were responsible forthe distribution of Fe-ore. North–south shortening during the Trans-Hudsonorogeny resulted in structural thickening of the primary Mary River banded iron for-mation (BIF), local metasomatic removal of chert layers, the development of foliat-ed and lineated, specularitic hematite ore, and finally crenulation of the speculariticore. Lineations and crenulations plunge regionally to the southeast across a series ofsynforms. The Mary River Group is structurally repeated along a series of steeplywest- to southwest-dipping listric normal faults, best observed at Glacier Lake ~20km east of the Deposit 1 Mary River mine. An appropriately oriented set of topo-graphic lineaments evident in digital topographic images is likely the surface mani-festation of the extensional faults. At Glacier Lake, development of normal faultswas accompanied by local brecciation and facilitated fluid flow responsible for themetasomatic removal of chert and the formation of blocky ore, which locally over-prints specular ore. The normal faults explain the consistent metamorphic gradeacross the region despite the consistent southeast structural plunge, the repetition ofthe Mary River Group stratigraphy, and the exposure of a series of synclines withoutintervening anticlines. The normal faults may be products of the Mesoproterozoicextensional event that gave rise to the more northerly Bylot basins.

Type:	Communication, article de congrès ou colloque
Mots-clés ou Sujets:	gîtes de fer, géologie de l'arctique, géologie structurale
Unité d'appartenance:	Faculté des sciences > Département des sciences de la Terre et de l'atmosphère
Déposé par:	Benoit Saumur
Date de dépôt:	10 mars 2025 08:15
Dernière modification:	10 mars 2025 08:15
Adresse URL :	http://archipel.uqam.ca/id/eprint/18550

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