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Carbonate-hosted; base metals; Mackenzie Mountains; stable isotopes
Abstract:
The carbonate strata of the Mackenzie Mountains of Northwestern Canada are host to a large number of mineralized base-metal occurrences. Here, we present S, C, O and Pb isotopic data on carbonates, sulfides and sulphates from 22 showings hosted by Neoproterozoic, Lower Cambrian and Silurian-Ordovican and Devonian carbonate units. The S isotope data suggest that the source of S in all the deposits is variable and some may be derived locally. The Pb isotope data have consistent values for most of the showings and suggest a single Pb source for the mineralization, similar to the Pb found in the SEDEX deposits of the Selwyn Basin. Carbon isotopic data suggest that the fluids that formed the deposits have C which is derived from the host carbonates with some input from an organic source. The oxygen data suggest that the mineralizing fluids have compositions that are strongly rock buffered. In total, these data allow a model of a regional hydrothermal fluid flow event in the Mackenzie Mountains that deposited base metals in units of varying ages.
