New structural, geochronological, and geochemical constraints on the tectonic assembly of the Archean Pickle Lake greenstone belt, Uchi subprovince, western Superior Province

New field work, U-Pb zircon ages, and geochemical data, including Sm-Nd isotopic analyses, have refined the timing and nature of volcanism, deformation, and tectonic assembly of the Pickle Lake greenstone belt in the Uchi subprovince of the western Superior Province of the Canadian Shield. Based on continuous stratigraphic marker units and geochemistry across a previously inferred fault contact, as well as pillow tops indicating consistent northwest-younging, the ca. 2890 Ma Pickle Crow assemblage has been redefined to include the former Northern Pickle assemblage. The Pickle Crow assemblage consists of tholeiitic basalt with thin, but laterally extensive, oxide-facies iron formation overlain by juvenile OIB-like basalts (i.e., niobium-enriched basalts) and minor calc-alkaline andesites to dacites (initial epsilonNd = +1.8--+2.2) suggestive of deposition in a sediment-starved oceanic basin. (Abstract shortened by UMI.)...