RE:RE:Synopsis of the Polaris Zn-pb District, Canadian Arctic IslaTraps7. Thank you for all the info, especially the link to the synopsis. It makes me feel a lot more comfortable investing in a company when I understand the geology.
If I undertand correctly, the two main criteria for target selection seem to be:
1) Gravity anomaly. However, “the gravity anomaly is influenced more by the large body of dolomite within limestone rather than sulphide within dolomite.”
2) The position in the stratigraphic sequence. The depositional model at Polaris: "Metals are then carried in sulphate-rich brines through deep aquifers. Driven by an orogenic process, circulating fluids rose along faults until they encountered organic-rich, permeable limestone) overlain by impermeable shale". i.e. the deposit was formed by fluids trapped under an overlying impermeable layer. The target areas therefore need to be east/downdip of the surface contact between a relatively permeable layer and an impermeable layer. In Polaris’ case, this meant east of the surface contact of Thumb Mountain (permeable layer) and Irene Bay Formations (impermeable layer). This is illustrated in Figures 8 and 14. In the Aston Bay case, it appears they are looking not only looking at Thumb Mountain as the host formation, but are also targeting permeable layers below the Bay Fiord Formation. Possibly the required depositional environment is a bioturbated carbonate as at Polaris. That model would fit the deposit at Seal, if the host formation is an extension of the Eleanor River Formation shown in figure 3 of the synopsis.
Unfortunately, after all that, I still haven’t been able to determine the answer to my question regarding the unmarked anomalies at Seal South, because Thumb Mountain could still be a host in an area of relatively high permeability ("Soil samples returned anomalous results of up to 10,600 ppm zinc within the Thumb Mountain Formation host to Polaris, which is underlain by several gravity anomalies including S4, S7, and S8."). There are obviously a few more factors that the geologists know about that they aren’t sharing, but in their defence, 99% of investors don’t care to know anyway.
The good news is that there is a lot of study on the Polaris mine and depositional environment which provides valuable info about marker beds etc which will greatly increase the efficiency of the drill program.
PS: If you look at the placement of the previous Seal South boreholes on the gravity map, you can see they were placed in about the worst areas possible, with respect to both the gravity survey and the depositional model. That is another example of why you want your explorers to spend a lot more money on research and geophysics. Blind drilling is just a waste of money.