With over a dozen years experience wouldn't you realise that...

With over a dozen years experience wouldn't you realise that assumptions and unjustified conclusions are what get us into trouble in geology? Two photos absolutely aren't enough for you or I to assign a deposit model to an area that still hasn't even been fully assessed.

Yes, there is the possibility that the veins and late stage ore-mineral shoots are a result of 'epigenetic mineralisation' - hence epigenetic. If we are going to be assigning deposit models at this early stage, I suggest that we may be seeing a combination of VMS and epithermal characteristics, or a 'high-sulfidation deposit in the VMS environment' - cue the academic literature (Sillitoe et al., 1996). I'd also like to point out Gold-rich VMS deposits of Dubé et al. (2007). In this subtype we see characteristic VMS sulphide textures and morphology, with 'complex assemblages of minor phases including bornite, tennantite, sulphosalts, arsenopyrite, mawsonite, and tellurides' in metamorphosed greenstone terranes - which is the predominant metamorphism we see in the Bryah Basin. What is apparent now is that to say anything for certain about Wodger we need more information. I hope you consult these papers as they provide much to think on and consider.

For context, it could even be argued that Monty is one of these gold-rich 'epithermal-esque' deposits - where the local variations in host-rock lithology, mixing-cooling histories of hydrothermal fluids (+/- magmatic fluids), and seawater chemistry affect the presence of these minor sulphide phases.

Regardless of what exact deposit model we choose for the area, there is no denying that there is something exciting here - how often do we find minor bornite and chalcopyrite outside of a larger mineralising system? VMS is an end member, epithermal deposits are an end memeber - but there are a myriad of possibilities in between.



The full references should you wish to consult them:

Dubé, B., Gosselin, P., Mercier-Langevin, P., Hannington, M., and  Galley, A., 2007, Gold-Rich Volcanogenic Massive Sulphide Deposits: in Goodfellow, W.D., ed., Mineral Deposits of Canada: A Synthesis of Major Deposit-Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication No. 5, p. 75-94.
Sillitoe, R. H., Hannington, M. D., and  Thompson, J. F. H., 1996, High Sulfidation Deposits in the Volcanogenic Massive Sulfide Environment: Economic Geology, v. 91, p. 204-212.