The Rusty Springs prospect is a carbonate-hosted Pb-Zn-Ag deposit in the northern Ogilvie Mountains. It is hosted in medium to coarsely crystalline grey dolostone and dolostone breccia of the Devonian Ogilvie Formation.
The Rusty Springs prospect has the basic characteristics of a Mississippi Valley-type deposit. It is hosted in dolostone, which is locally brecciated. The ore occurs at shallow depths and there are no associated igneous rocks. Also, hydrocarbon, which is a common feature in these deposits, is present at Rusty Springs in the form of pyrobitumen. However, several features are at variance with the Mississippi Valley-type classification. The abundant, exceptionally coarse, crystalline quartz and high silver values are evidence for a hydrothermal origin.
