Some two billion years ago the Askot deposit was formed when a long episode of volcanic eruptions took place on a primordial ocean floor. Askot is a volcanogenic massive sulfide (VMS) deposit. These deposits are well studied. More than 1,000 occur around the world and they supply much of our global needs for metals.
To download a geologic map of the Mining Lease area (900k) click here. The map was made at 1:10,000 scale and is best printed on large paper. It also shows the surface projection of the Askot deposit (in red) and the electromagnetic anomalies (in black).
The deposit occurs in an assemblage of amphibolites, cherty breccias, various schists derived from volcanic tuffs and sediments, and diorite and granitic intrusive rocks, all Proterozoic in age. The rocks are tightly folded into an overturned syncline.
Geologist examining the mineralised back (roof) in the 985-level drift. The black colour is an assemblage of sphalerite (zinc), chalcopyrite (copper), galena (lead), silver and gold; the orange is iron oxide stain; the white is quartz-bearing breccia. A channel sample across this zone reported 2.42% copper, 8.40% lead, 11.45% zinc, 187gpt silver and 2.3gpt gold.
The mineralised zones are stratiform. Several drill holes cut two to five parallel beds or lenses. The principal zone dips 65 to 80 degrees northeast. It extends at least 600 metres along strike, from northwest to southeast. Previous agencies drilled to an average depth of 180 m, the limit of the equipment used at the time. Its average true thickness is about 2.5 metres, up to a maximum of 15 m. It is open (untested) along strike to the northwest, to the southeast, and down-dip through the keel of the syncline.
Four generations of ore controls are superimposed: stratigraphic stacked lenses; isoclinal folds on north-south axes; open folds that plunge 15 degrees northwest, parallel to the axis of the main syncline; and post-folding, cross-cutting faults that displace the deposit from a few to some tens of metres in various places.
(June 27, 2011)