Geochemical Analysis Results of Rock Samples of Economic Interest
The table of lithogeochemical analyses of samples of economic interest presents the analytical results of mineralized rock samples collected during the Ministère‘s yearly geological mapping campaigns across Quebec for elements of economic interest. Mineralized sites with values exceeding “showing” thresholds (table below) are subject to a “Mineralization record” in the metallic deposit module of the Quebec Geomining Information System (SIGÉOM). “Anomalous” and “significant” thresholds (table below) highlight samples below showing threshold, but sufficiently high to be of interest for mineral exploration.
The sequential number in the first column links to the corresponding analysis in the SIGÉOM database. A hyperlink is also provided to the interactive map to locate the analytical result in question.
The “complete” display, under “Display Format” in the left-hand panel, lists all the analyses and elements available in the area of interest.
SHOWING, ANOMALOUS AND SIGNIFICANT THRESHOLDS FOR GEOCHEMICAL ANALYSES
An analysis yielding a value above or equal to showing threshold for a given element. A mineralization record is created in the SIGÉOM database (metallic deposit section in SIGÉOM à la carte).
Anomalous and Significant Thresholds
Anomalous and significant thresholds were determined using statistical processing on a SIGÉOM database of 338 089 analyses dated June 2017. No distinction was made as to the source of the data or the analytical method.
Elements analyzed are: Ag, Au, Be, Co, Cr, Cu, EGP, Fe, Li, Mn, Mo, Nb, Ni, Pb, Pd, Pt, REE, Rh, Sb, Sc, Sn, Ta, Th, Ti, U, V, W, Zn and Zr.
These thresholds allow extracting the “near showing” analyses. Example: 0.4 g/t of gold in a sample may be of interest to exploration companies. The 95th percentile was calculated for each element. 95% of contents are below this value and 5% above. Results were retained and found to be statistically reliable for Ag, Au, Cr, Cu, Fe, PGE and REE. For other elements, adjustments were required to obtain cut-off values expressed as percent of the showing thresholds:
– 30% of showing treshold: Be, Co, Li, Mn, Mo, Nb, Pb, Pd, Pt, Sb, Sn, Ta, Y, Zn and Zr;
– 50% of showing treshold: Th, V and W;
– 75% of showing treshold: Ti.
An analysis yielding a content that differs statistically from the entire geochemical database (mineralized and non-mineralized rocks), but that is still below the anomalous threshold. The 1-sigma of the normal distribution, namely the 84th percentile, was calculated. The rounded results are considered appropriate for all elements, with the exception of Be, for which a cut-off value at 10 times the detection limit was preferred, and U, for which a cut-off value at 10% of its anomalous threshold was found to be more consistent.
North (green) and south (orange)
|Element||Significant Treshold||Anomalous Treshold||Showing Treshold||Unit|
|Fe||110 000||200 000||300 000||ppm|
|Mn||1700||30 000||100 000||ppm|
|Rare earth elements (REE)||250||1500||1700||ppm|
|Ti||8000||75 000||100 000||ppm|