The Gastineau occurrence is located on a high ridge, east of the Quatam River.

Locally, a chalcopyrite showing occurs in an area underlain by rocks of the Lower Cretaceous Gambier Group. These consist of greenstone, volcanic breccia, argillite, minor conglomerate, limestone and schist. Quartz monzonite of the Jurassic-Cretaceous Coast Plutonic Complex occurs within a few hundred metres to the south.

In 2007, Archangel Resources took rock samples from the area. In 2010, AZ Copper completed a program of rock and soil sampling.