Tectonic evolution of the northern Pickle Lake greenstone belt, northwestern Superior Province, Ontario

The northern part of the Pickle Lake greenstone belt was previously thought to comprise two volcanic assemblages termed the Northern Pickle (inferred to be ca. 2990 Ma) and the Pickle Crow (ca. 2892 Ma) assemblages. Structural evidence and aeromagnetic patterns suggest that the inferred tectonic boundary between these two assemblages may not be significant and that this part of the belt may belong to a single composite Northern Pickle–Pickle Crow assemblage. Evidence for at least three deformation events is recognized: 1) an early, local planar fabric predating 2860 Ma; 2) the main regional foliation (S1), bracketed between 2860 Ma and 2742 Ma; and 3) F2 folds and overprints of the regional foliation associated with the emplacement of plutonic bodies at ca. 2741 Ma. A regional ‘Kenoran’ fabric of post-Confederation age has not yet been recognized in the northern part of the Pickle Lake belt. 2001-C20 M. Young and H. Helmstaedt 1 CURRENT RESEARCH RECHERCHES EN COURS 2001 Article Article Titles Titres Purchase Information Information pour acheter 1 Contribution to Western Superior NATMAP Project 2 Department of Geological Sciences, Queen’s University, Kingston, Ontario K7L 3N6