The Cindy occurrence consists of copper mineralization immediately north of Franklyn Arm of Chilko Lake.
The occurrence is in Lower Cretaceous volcanic and sedimentary rocks of the Gambier overlap assemblage (Geological Survey of Canada Map 1713A). It is about 2 kilometres southwest of an important northwest-striking fault, the Stikelan fault, and about 9 kilometres north of the Early Tertiary Tiedemann pluton of the Jurassic to Tertiary Coast Plutonic Complex (Geological Survey of Canada Open File 1163).
The Lower Cretaceous unit hosting the occurrence comprises bedded andesitic and basaltic volcanic tuffs and breccias, and rhyolitic tuffs and flows with spherulitic textures (Bulletin 81; Geological Survey of Canada Open File 1163). Interbedded with the volcanics are epiclastic sedimentary rocks including quartz-rich greywacke, cherty conglomerate, minor limestone and argillite (Assessment Report 3319). Bedding strikes north-northwest and dips moderately steeply east; some rocks are foliated.
The rocks are intruded by bodies of quartz-feldspar porphyry of possible subvolcanic origin, and reportedly by quartz diorite and granodiorite probably related to the Coast Plutonic Complex (Bulletin 81; Assessment Report 3319).
The main mineral showings occur in volcanic or limy sedimentary rocks (Bulletin 81; Assessment Reports 3319, 3949). They are gossanous due to the oxidation of pyrite and pyrrhotite which are disseminated or localized along fractures or in massive pods. Minor chalcopyrite and malachite are also present locally. The mineralization is generally associated with variably-oriented quartz or epidote-calcite veinlets.
Rock samples from the mineralized zones contain anomalous silver, copper, lead, zinc and iron (Bulletin 81). One sample was analysed to contain 0.3 per cent copper and 5 grams per tonne silver. Two other samples contained 0.29 and 0.17 per cent copper, respectively (Bulletin 81).
This occurrence has been interpreted as an example of volcanogenic massive sulphide mineralization (Bulletin 81).