Nepheline syenite gneiss occurs as a concordant lenticular mass at Trident Mountain, approximately 85 kilometres northeast of Revelstoke.

The area surrounding Trident Peak consists of a light coloured banded nepheline syenite body. The syenites were emplaced circa 380 Ma (uranium-lead isotope date from zircons, Open File 1991-10) and intrude psammatic and kyanite-bearing pelitic schists of the Hadrynian Horsethief Creek Group.

The nepheline syenite-gneiss occurs in the core of an undulating, recumbent nappe forming a lenticular body, diminishing in thickness to the northwest and southeast. The syenite gneisses are concordant with the host rocks. The rock is white to grey, medium (1 to 5 millimetres) to coarse-grained (greater than 5 millimetres) and consists of microcline, albite and nepheline with minor biotite, ilmenite, sodalite, cancrinite, calcite, apatite, sphene, pyrochlore and zircon (Open File 1987-17). The composition of three samples collected is:

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           Major oxides            Weight (per cent)
           SiO2                    55.59 - 63.70
           Al2O3                   20.73 - 24.69
           Fe2O3                    0.17 -  0.59
           CaO                      0.56 -  1.20
           Na2O                     8.16 -  8.39
           K2O                      3.12 -  8.22
           -----------------------------------------

A 20-kilogram sample, sent to CANMET, was crushed and passed through a magnetic separator with the following results:

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     Mesh       Magnetic concentrate      Nonmagnetic concentrate
                              (Weight in per cent)
     -10 + 35           4.1                         67.7
     -35 + 100          1.3                         19.8
     -100               0.5                          6.6
     ------------------------------------------------------------

Analyses of the nonmagnetic concentrate are:

----------------------------------------------------------------
   Major oxides     -10 + 35 mesh     -35 + 100 mesh      -100 mesh
                                   (Weight in per cent)
   SiO2                 56.6               58.0              62.0
   Al2O3                16.8               17.3              18.5
   Fe2O3                 0.07               0.03              0.10
   CaO                   0.75               0.76              0.95
   Na2O                  6.11               5.79              5.63
   K2O                   7.59               8.05              8.31
   ----------------------------------------------------------------

Processing results indicate that the nepheline syenite is low in magnetic impurities, has a high recovery rate of nonmagnetic materials and has, therefore, a very good potential to produce commercial grade nepheline syenite. Processing indicates a product brightness of 85 per cent can be obtained.

Samples tested are comparable to nepheline syenite currently imported into western Canada from Ontario. Geological mapping by Pell (Open File 1987-17) has documented large lenticular bodies of nepheline syenite over a distance of 7 kilometres at Trident Mountain. This large body has excellent potential to contain nepheline syenite similar to the samples tested. The samples tested were from float located approximately two kilometres north of Trident Mountain peak. Preliminary processing data indicates that a product of 85 per cent brightness can be obtained (McVey. H, 1988, Mineral Development Agreement, Report 4).

At the mouth of Trident Creek, which drains the area, placer uranium, thorium and niobium has been recorded (082M 077).