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File Created: 24-Jul-1985 by BC Geological Survey (BCGS)
Last Edit:  01-Apr-2010 by Sarah Meredith-Jones (SMJ)

Summary Help Help

Name TRIDENT MOUNTAIN Mining Division Golden
BCGS Map 082M100
Status Developed Prospect NTS Map 082M16E
Latitude 051º 54' 20'' UTM 11 (NAD 83)
Longitude 118º 09' 04'' Northing 5751160
Easting 420811
Commodities Nepheline Syenite, Feldspar, Rare Earths Deposit Types R13 : Nepheline syenite
Tectonic Belt Omineca Terrane Kootenay
Capsule Geology

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:


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:


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).

EMPR FIELDWORK 1985, p. 255; *1988, p. 486
EMPR OF *1987-17, pp. 48-50; 1991-10
EMPR PF (*Russel, F.T. (1956): Report on #223 Prospecting
GSC BULL *239, pp. 179-180
GSC MAP 12-1964
GSC OF 637
GSC P 64-32, p. 14
McVey, H. (1988): A Study of Markets for British Columbia's Nepheline
Syenite and Feldspathic Minerals, MDA Report 4, B.C. Ministry of
Energy, Mines and Petroleum Resources p.46
Perkins, M.J. (1983): Structural Geology and Stratigraphy of the
Northern Big Bend of the Columbia River, Selkirk Mountains,
unpublished Ph.D. Thesis, Carleton University