Structural setting of the Cornwallis lead-zinc district, Arctic Islands, Nunavut

Abstract

Zinc-lead mineralization of Devonian to Carboniferous age in the Cornwallis district is spatially related to faults and folds of the Boothia Uplift. The north-south elongate Boothia Uplift, formed during Caledonian (Late Silurian - Early Devonian) compression, is characterized by west-verging, basementrooted thrusts and related folds in cover strata. Southward compression during the Ellesmerian Orogeny (Late Devonian - Early Carboniferous), perpendicular to these older faults, reactivated them as strike-slip structures. One effect of this reactivation was the creation of transverse fracture zones where stress was transferred between basement blocks. Mineralizing fluids driven by the Ellesmerian Orogen migrated through these fracture zones and into permeable lower Paleozoic units. This style of mineralization is one of several present in the Cornwallis lead-zinc district.

Timing and metal sources for carbonate-hosted Zn-Pb mineralization in the Franklinian Basin (North Greenland): Constraints from Rb-Sr and Pb isotopes

“…Within errors, our Rb-Sr age for KCL is concordant with the Upper Devonian age of the carbonate-hosted Polaris Zn-Pb deposit in the western, Canadian part of the Franklinian Basin, as been established through paleomagnetism (367 ± 7 Ma; Symons and Sangster, 1992), Rb-Sr dating of sphalerite (366 ± 15 Ma; Christensen et al, 1995b) and Re -Os dating of bitumen (374 ± 9 Ma; Selby et al, 2005). There is consensus among these studies that migration of ore-forming fluids and hydrocarbons were initiated by the approaching compressive Ellesmerian orogenic front (Turner and Dewing, 2002;Dewing and Turner, 2003). The older age established for the three Peary Land occurrences (i.e., 388 Ma), can possibly be accounted for by their more proximal location to the orogeny, which would have implied a shorter pathway for the mineralizing brines.…”