Geological Survey Activity Tracker

Flin Flon Belt and Kisseynew


Snow Lake VMS: an investigation of the precious metal occurrences, metamorphism and alteration of selected VMS deposits from the Snow Lake area

Project Status: Completed (2019)


Click to enlarge imageProject Information

Principal investigators:
Simon Gagné

Partnered with:
Targeted Geoscience Initiative 3 (TGI-3), McGill University

Snow Lake, 63K/12: focus on Lalor and Chisel North deposit


Project Description

Main objectives:

The Snow Lake VMS deposits have experienced peak metamorphic conditions varying from lower to mid-amphibolite facies. The main objective of this project is to study the effects of metamorphism on massive sulphide deposits and their associated alteration envelope with a focus on oxidation-sulfidation-desulfidation reactions and precious metals remobilization.


  • Re-logging and sampling of selected drill holes that provides a representative section through a typical massive sulfide deposit and its alteration envelope.
  • Careful petrographic examination of the variation in mineral assemblages will be documented.
  • Electron-microprobe analysis will provide mineral chemistry data. Schreinemakers analysis, pseudo-section modeling and mineral phase equilibria will be used to investigate the factors controlling the formation of characteristic mineral assemblages.
  • Particular attention will be paid to gahnite, a zinc-bearing spinel commonly found as an accessory phase in the alteration envelope of some amphibolite-grade VMS deposits.
  • Another focus of the study will be evaluation of the zones with elevated precious metal content found within and around some massive sulphide lenses of the Snow Lake area. The project will attempt to determine what parameters control the precious metals distribution and how metamorphic processes may have influenced it.



The project will provide a better understanding of the various factors controlling the formation of indicators minerals, and the composition and chemistry of alteration haloes around metamorphosed VMS deposits. The investigation will also provide new insights on the behavior of precious metal during metamorphism with a special attention given to the parameters controlling remobilization and the scale of the processes involved.


Completed outputs:


Gagne, S., Williams-Jones, A.E. and Hynes, A. 2011: Multiple origins for gahnite at the Lalor Zn-Cu-Au deposit, Snow Lake (Manitoba), and implications for mineral stabilities during metamorphism; oral presentation at Geological Association of Canada – Mineralogical Association of Canada Joint Annual Meeting 2011, Ottawa, Ontario, May 25-27.

Gagné, S., Williams-Jones, A.E., Hynes, A. 2011: Multiple origins for gahnite at the Lalor Zn-Cu-Au deposit, Snow Lake (Manitoba), and implications for mineral stabilities during metamorphism (abstract); Mineralogical Association of Canada; Geological Association of Canada, Joint Meeting 2011, Ottawa, ON, May 25-27, 2011, Abstracts volume, v. 34, p. 70.


Gagné, S., Beaumont-Smith, C.J., Williams-Jones, A.E. and Hynes, A. 2007: Investigation of a Pb-Ag-Au–rich hangingwall in lens 4 of the Chisel North mine, Snow Lake, Manitoba (NTS 63K16): preliminary results; in Report of Activities 2007, Manitoba Science, Technology, Energy and Mines, Manitoba Geological Survey, p. 43–50.

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