Soil Geochemistry

Mouse Mountain has been extensively soil sampled; the overburden is thin and the geochemistry is thought to reflect the bedrock chemistry better than in areas with thick glaciofluvial cover. The main soil geochemistry was done by Placer Dome Inc and by Teck
Exploration Ltd. Earlier work was done by First Nuclear Corp and is reported by Stewart 1982 and 1984 and by Climie, 1985. Figure 16 is a summary map of the copper soil geochemistry over Mouse Mountain defined by the surveys reported by Sanguinetti (1989), Fox (1989) and replotted for this report.

The map shows that the anomalies follow north-northwest trending zones. One zone, about 1.5 km long, includes the known showings. The other zones, to the northeast and southwest parallel the main zone, but lack known showings. This general north-northwest trend of the geochemically responsive zones conforms to the trend of the geology and ground and airborne total field magnetics.

Mouse Mountain soil geochemical results for copper. Here the copper soil geochemical anomalies from 1989 Placer Dome Inc (PDI) are shown as the coloured surface and individual sample localities are coloured to reflect the copper results. Anomalous copper threshold is about 100 ppm. These data are reported by Fox (1989) Sanguinetti (1989). Note that the geochemical soil response is good at Valentine and Rainbow but less so at the High Grade.

The figure above shows that the copper results from the Placer Dome survey define an anomalous zone at the southeast of the grid. This zone was explored by Richfield during the summer of 2006 when the grid was extended southeastward. The copper results of the combined survey, given in the figure below, show that the anomalous zone does not extend southeast. The new data do outline a fresh high copper response zone east of the PDI grid.

Map of the combined results of the historic PDI soil geochemistry and 2006 resultsrom the Richfield extension to the grid. Note the different sample density. The anomalous zone at the SE of the PDI grid does not extend southeastward but the new data define a new zone of copper response east of Mouse Mountain.

The figure below is a map of the combined results of gold in soils from the historic PDI survey and the new RVC survey.

This map shows the gold soil geochemistry from the combined PDI and RVC surveys over Mouse Mountain. Note that the known showings are not reflected in the gold soil geochemistry, but that the high gold responses follow the same mineralized corridor defined by the showings and the copper geochemistry.

As noted iron carbonate alteration, consisting of ankerite and/or ferrodolomite with associated minor quartz stringers that resembles listwanite alteration of ultramafic rocks, is seen commonly at Mouse Mountain. This alteration is later than the youngest rocks, namely the syeno-monzonite and may represent a late or post diagenetic event. In places it is spatially associated with minor faults that cut the rocks. It forms irregular zones overprinted on the country rocks. The zones are roughly equant, do not follow Lithology as far as that can be determined and have gradational nebulous boundaries. The alteration is not strictly confined to the mineralized showings but it is common there. At least locally the iron carbonate alteration is later than copper mineralization. To determine if the altered zones are reflected in the soil geochemistry plots of Ca times Fe were made from the historic and new geochemical results. A map of these plots, given in the figure below, shows that the geochemistry does indeed reflect the altered zones and that the zones so defined coincide with the known showings. The map shows several high Ca by Fe zones where no showings are known. These areas need to be followed up.

Map of the geochemical results for iron and calcium multiplied for the PDI and RVC soil surveys. The aim is to outline iron carbonate altered zones. Known showings are at Ca by Fe highs and note that several such highs lack known showings. Also note the northwest trending zones defined by the geochemically responsive zones. These correspond closely with the mineralized corridor and also with the high copper and high gold response zones.