The Cow 10 occurrence is located on the ridge separating Chipman Creek to the north and the Chemainus River to the south. The community of Lake Cowichan is located approximately 8 kilometres to the southwest.
Regionally, the area is underlain by chert, siliceous argillite and siliciclastic rocks of the Mississippian to Pennsylvanian Fourth Lake Formation (Buttle Lake Group) and volcaniclastic rocks of the Middle to Upper Devonian Mclaughlin Ridge Formation (Sicker Group). These rocks are intruded by granodiorite and quartz diorite of the Early to Middle Jurassic Island Plutonic Suite and gabbroic to dioritic rocks of the Triassic Mount Hall Gabbro. Undivided sedimentary rocks of the Upper Cretaceous Nanaimo Group locally overlay the previous units.
The occurrence area is underlain by the Mississippian to Pennsylvanian Fourth Lake Formation (Buttle Lake Group). These sediments form a northwest-trending succession of interbedded argillite, cherty sediment, siltstone and sandstone, with minor conglomerate, crystal tuff and marble. A northwest-trending, 30-metre wide gabbroic dike (Triassic Mount Hall Gabbro) intrudes the strata northwest of the occurrence, and a stock of quartz diorite and diorite of the Early to Middle Jurassic Island Plutonic Suite is present to the southwest.
Locally, an approximately 10-metre thick ferruginous chert (iron formation) horizon has been traced for 700 metres. This bed is generally composed of blue-grey cryptocrystalline quartz (sporadically jasperoidal) with up to 5 per cent each of pyrite and specular hematite and a few per cent magnetite.
In 1986, a sample (1620) of the chert material assayed 0.300 grams per tonne gold, and a nearby sample (1684) of chert fragmental hosting disseminated pyrite and trace chalcopyrite yielded 0.054 per cent copper and 0.053 per cent tungsten (Assessment Report 15013, 16053).
In 1987, drillhole CH87-1 intercepted 22.53 metres (75.70 to 98.24 metres down hole) of ferruginous, magnetic chert with disseminated and fracture-filling pyrite hosting anomalous gold values yielding from 0.02 to 1.13 grams per tonne gold (re-samples yielded from 0.11 to 0.13 gram per tonne gold), and drillhole CH87-2 yielded 0.40 gram per tonne gold over 0.56 metre of argillite hosting a silicified zone with pyrite and pyrrhotite (Assessment Report 16053).
A siliceous, magnetite and pyrite-rich boulder was found a few hundred metres to the northeast of the ferruginous chert. Sulphides and magnetite occur in bands up to 5 centimetres thick. In 1986, a rock sample (No. 356) of this material contained up to 4.80 grams per tonne gold, and a nearby float sample (1696) of massive-sulphide (pyrite - chalcopyrite ± sphalerite) layers in a fine-grained siliceous (quartz-chlorite) host yielded 1.84 per cent zinc, 0.10 per cent copper and 2.6 grams per tonne silver (Assessment Reports 15013, 16053).
Another siliceous boulder from the same area as the previous sample contained up to 40 per cent sulphide-rich bands, consisting of pyrite, chalcopyrite and sphalerite. In 1986, a sample (14843) of brecciated, hematitic, cherty sediment float found a few hundred metres to the northwest of the iron-rich chert exposure assayed 1.44 grams per tonne gold (Assessment Report 16053).
An exposure of rhodonite is reported near the peak of the hill to the southeast of the occurrence. In 1987, a sample (1962) yielded 0.05 gram per tonne gold and greater than 0.99 per cent manganese (Assessment Report 16053).
Approximately 1200 metres to the northwest of the occurrence an area of angular float comprising fine-grained gabbroic material hosting disseminated pyrite, magnetite and possible pyrrhotite contain anomalous gold, copper and vanadium values. In 1986 and 1987, float samples (1625 and 811) yielded values of up to 0.190 gram per tonne gold, 0.152 per cent copper and 0.231 per cent vanadium (Assessment Report 15013, 16053).
Work History
In 1986 and 1987, International Cherokee Development completed programs of geochemical sampling, geological mapping, ground geophysical surveys and two diamond drill holes, totalling 213.0 metres, on the area as the Cow 10 claim of the Chem property.
In 1992, GLS Global Listing Service Limited completed a program of rock and soil sampling on the area as the Cow 7, 9-11 claims of the Chem property.
