The area around the headwaters of Azure River has claimed attention for several years on account of the discovery of large bodies of auriferous quartz in metasedimentary rocks of the Shuswap Metamorphic Complex. The Summit mineral showing is located on a ridge between the Azure River and Hobson Creek, approximately 7.6 kilometres south of the headwaters of the Azure River.
The Summit mineral showing lies near the contact between the Hadrynian Upper Kaza Group and the stratigraphically overlying Isaac Formation of the Hadrynian Cariboo Group. The ground covering the Summit mineralization is on the crest and northeast limb of a major anticline which plunges at a low angle to the northwest. The country rock is predominantly rusty weathering, quartz-sericite schist, striking west and dipping 70 degrees north. Lesser amounts of impure quartzite, pebble conglomerate and interbedded limestone of the Isaac Formation also occur. Lithologies of the Hadrynian upper Kaza Group consist of quartzo-feldspathic psammite, phyllite, slate and minor grit.
All the mineralization on the property is quartz-filled fissures containing pyrite, locally accompanied by galena, chalcopyrite, sphalerite, and rare amounts of tetrahedrite and arsenopyrite. Quartz veins all dip steeply and tend to strike one of four principal directions. The general structure strikes an average of 300 degrees. Other sets strike 330 to 340 degrees and 20 to 30 degrees. Those which strike 20 to 30 degrees are the most prominent as to size and most frequently contain sulphides. Those veins which are in quartzite, tend to have many branches that leave the parent in one or more sets and pinch out at 5 centimetres to 15 metres. All wide quartz veins terminate abruptly.
The quartz within veins is white and crystalline and sulphides are erratically distributed as scattered grains, as veins and as pockets and smears. Pyrite tend to be either intercrystalline with quartz or shattered and veined by quartz. Galena, sphalerite and chalcopyrite with associated gold are distinctly later than, and found as veinlets in, the pyrite. Siderite, light when fresh, weathers deep brown to reddish and occurs in many veins as a common constituent. Sericite is locally present and likely represents digested remnants of schist inclusions.
At the main showing, the Horne tunnel (adit) is driven back about 7.5 metres into the base of a ridge. Near massive sulphides, consisting of a fine assemblage of pyrite, sphalerite, chalcopyrite and galena, occur along segments of the adit walls. Other portions are lightly mineralized with pyrite. Disseminated mineralization occurs up to 30 centimetres into host schists. Three samples were taken from the adit area and assayed as follows (Minister of Mines Annual Report 1938).
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SAMPLE LOCATION Au(g/t) Ag(g/t)
1 east wall of adit 2.13 to 3.66 metres 4.80 10.29
back from portal.
2 11 metres from portal; 60 centimetre 41.14 54.86
chip sample.
3 3 metres above portal; 132 centimetre 10.29 10.29
chip sample on surface.
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Approximately 677 metres northwest along regional strike (100/70NE) of a major fold, three quartz masses crop out within 60 metres of each other. One of these, an open cut measuring 2.44 metres wide by 6.0 metres long, exposes considerable siderite and locally a little pyrite in quartz veins. Small outcrops of quartz extend for 61 metres to the northwest and 76 to 122 metres to the southeast. These outcrops of quartz stringers and veins host disseminated pyrite, galena and arsenopyrite. A sample from this open cut assayed 30.17 grams per tonne gold and 17.14 grams per tonne silver (Minister of Mines Annual Report 1938).
