Colloque

Geology of the Minto block, northeastern Superior Province

Ken D. Card

John A. Percival

Richard A. Stern

Thomas Skulski

Membre a labase

Ken D. Card

Résumé du colloque

Recent mapping and geochronology (1989-1993) of a transect across the Ungava Peninsula in the 250,000 km² high-grade Minto block of the northeastern Superior Province reveal four domains of dominantly plutonic origin (west to east: Tikkerutuk, La Minto, Gouldia, Utsalik), forming northerly structural and aeromagnetic trends. The voluminous Leaf River granodiorite suite of 2.725 Ga age occurs in all domains and isotopically reflects derivation from sources 2.8-3.1 Ga that occur locally as tonalitic enclaves. The Gouldia domain, forming a central spine, contains significant 3.1-2.9 Ga tonalite and the Vizien greenstone belt, consisting of volcanic-sedimentary panels of 2.94, 2.80, 2.724 and c.2.718 Ga age, assembled from continental and oceanic deposits. Younger regional magmatism of isotopically evolved composition and inferred crustal derivation includes a 2.712 Ga diatexite suite in Lake Minto domain, and widespread leucogranite of 2.69 Ga age. Significant previously unrecognized mineral potential (base metals, gold) exists in island-arc type volcanic rocks of the Gouldia domain, which appears aeromagnetically to extend hundreds of kilometers north and south of the transect.