Altered Jowett Formation

Photograph of the Jowett Formation exposed in Broadview Creek. These rocks commonly include magnetite which makes them readily identifiable on geophysical surveys.

Altered Jowett Formation

The Jowett Formation is exposed in Broadview Creek, and is very difficult to access because it forms a number of cliffs in the area. The volcanic rocks are prone to alteration that makes a dark green color, and is due to the presence of epidote, chlorite and amphibole in the rock.

Until fairly recently, these rocks were poorly understood, but a detailed petrological study of them conducted in 2022/23 has shed considerable insight into the importance of the Jowett Formation at Thor.

Being volcanic rocks, these rocks are much more amenable to the classic porphyry copper-style of alteration that is found in British Columbia, unlike the Broadview and Sharon Creek Formations that are sedimentary rocks and contain an entirely different type of alteration pattern found around the epithermal deposit, and the prospective porphyry deposit at depth.

Where this formation is exposed along the Thor access road, it contains extensive albite which is an indicator of pottasic alteration around a porphyry deposit. Taranis believes that the extensive alteration seen in this rock unit is due to a much larger intrusive body that is concealed under the Thor epithermal deposit.

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