Tsitsutl Mountain rhodonite occurrence, Tsitsutl Mountain, Omineca Mining Division, British Columbia, Canadai

Regional Level Types
Tsitsutl Mountain rhodonite occurrence	Occurrence
Tsitsutl Mountain	Mountain
Omineca Mining Division	Mining Division
British Columbia	Province
Canada	Country

Latitude 054º 58' 35'' North; Longitude: 125º 37' 56'' West. A rhodonite-bearing vein occurs at about the 1,675 metre elevation on the north side of Tsitsutl Mountain, about 20 kilometres east of Tochcha Lake and 102 kilometres east-northeast of Smithers, British Columbia.
Giles Peatfield comments:
There is a brief description of the occurrence, listed as a showing, on the British Columbia “Minfile” site, current to 2021. This description is quoted below:
“The Tsitsutl Mountain tin occurrence is plotted as being located at an elevation of approximately 1750 metres on the north side a ridge extending southeast of Tsitsutl Mountain. [Note that this precise location is questionable.]
Regionally, mudstone, siltstone, shale, fine clastic sedimentary rocks, and greenstone to ultramafic rocks of the Lower Permian to Upper Jurassic Cache Creek Complex have been intruded by Lower Cretaceous granodioritic rocks.
The showing comprises a northwest-striking rhodonite vein cutting the rocks of the Cache Creek Group. This vein consists of about 70 per cent rhodonite; 2 to 3 per cent arsenopyrite and variable amounts of calcite, spessartine garnet and ilmenite. The vein has been exposed over widths of 46 and 61 centimetres in two places. Analyses have shown the presence of minor amounts of tin (0.09 per cent), zinc (0.37 per cent), vanadium oxide (0.65 per cent) and cobalt as well as manganese (GSC Memoir 252 p.194 [Armstrong, 1949]).”
The Canadian Geochronology Knowledgebase does not show any radiometric ages for rocks in the immediate area of interest. MacIntyre et al. (1998) wrote that “The age of the Pyramid Peak pluton is not known at this time but it resembles other plutons in the area which have been mapped as the latest Jurassic (c.a. 145-147 Ma) Francois Lake Suite. Samples were collected from the pluton for U-Pb, and Ar-Ar radiometric dating.” I can find no record of the analysis of these samples. Armstrong (1949) originally included what is now known as the Pyramid Peak pluton in his Upper Jurassic or Lower Cretaceous Omineca Intrusions.
Giles Peatfield Comments on the Minerals Reported:
This list, while probably incomplete, includes those minerals specifically reported as occurring in the rhodonite-bearing vein and rocks in the immediate area.
Amphibole group: Goodall (1996) reported that the granodiorite contains “. . . dark green to black hornblende phenocrysts . . . .” This is a field identification only.
Arsenopyrite: Armstrong (1949) reported that the rhodonite-bearing vein contained “. . . 2 or 3 percent arsenopyrite . . . .”
Calcite: Armstrong (1949) reported that the rhodonite-bearing vein contained a variable amount of calcite.
Chromite: Chromite was observed by Goodall (1996) in one sample of granodiorite.
Feldspar group: Goodall (1996) reported that “The granodiorite contains large (3mm to 8mm) phenocrysts of plagioclase and orthoclase . . . .”, but provided no specific data for the plagioclase.
Garnet group: Armstrong (1949) reported that the rhodonite-bearing vein contained “garnet (spessartite [sic])” Note that this currently incorrect spelling of the garnet species name – spessartine – is repeated by Sabina (1964) and by Traill (1970, 1983). There is no more detailed information regarding this mineral.
Ilmenite: This putative mineral is of some interest here. Armstrong (1949, p. 134) reported ilmenite in the rhodonite-bearing vein, stating that “The ilmenite is probably the source of the vanadium, cobalt, and nickel.” However, subsequently in his report, Armstrong (1949, p. 194) wrote that “H. V. Ellsworth of the Geological Survey examined specimens submitted to him and reported on them as follows: ‘Chemical tests showed the presence of appreciable amounts of manganese, cobalt, and vanadium, with a very little copper and hardly more than a trace of nickel. Further investigation showed that the source of the manganese, cobalt, and copper is the black material sparingly present in the rock. As the vanadium test was by fusion, I cannot say without further tests whether the vanadium is also in this material. The amount of cobalt is small, I should think no more than 0·5 per cent. However, as the cobalt, manganese, and copper can be readily extracted from the powdered rock by treatment with acid, it would perhaps be worth while to investigate the occurrence on the chance that it might be a very large deposit or that richer material might be found.’” Armstrong (1949, p. 194) then went on to say “The ‘black material’ referred to by Ellsworth is probably [my emphasis] ilmenite, and there can be little doubt that it is the source of some of the vanadium, cobalt, and nickel found in the assays.” See further comment below for rhodonite.
Limonite: Goodall (1996) reported that the contact between intrusive and metasedimentary rocks “. . . is evidenced by strong limonitic staining and gossan.”
Mica group: Goodall (1996) reported that the granodiorite contains biotite phenocrysts, but again this is a field identification.
Pyrite: Goodall (1996) noted that “Coarse grained pyrite to 2% occurs throughout the quartzite and causes a strong limonitic stain on weathered surfaces.”
Quartz: Goodall (1996) noted “. . . rounded to[sic] clear to opaque quartz eyes . . . .” in the granodiorite intrusive rock.
Rhodonite group: This mineral was reported by Armstrong (1949, p. 134) and this identification has simply been copied in all subsequent reports. There is no evidence that any detailed analytical work or x-ray determination has ever been done on the material. Armstrong (1949, p. 194) wrote that “The Provincial Department of Mines assay office in Victoria reported on a sample of the rhodonite ·as follows: ‘Sample No. 1 contains manganese, tin, and zinc in amounts which suggest that the deposit may have commercial possibilities, particularly if samples can be obtained which contain a higher percentage of tin. No. 1 sample contained two- or three-tenths of one per cent tin.’ An assay on a specimen of rhodonite submitted to the Bureau of Mines, Ottawa, yielded 0·37 per cent zinc and 0·09 per cent tin. It was not assayed for manganese.” The presence of zinc and tin is interesting. Armstrong (1949, p. 134) commented that “The tin mineral was not identified.” There would appear to be a potential research project here to more clearly identify the details of the various minerals. However, the area is relatively remote, and as Leaming (1973, p. 58) commented “The vein is probably hard to find as it is only exposed along a length of 24 feet and is less than two feet wide.”
Note: There is the question of tin, and why this was called a tin-vanadium deposit [my emphasis] in Armstrong (1949). Minfile more correctly refers to it as a tin occurrence. Armstrong (1949) included a section (p. 194) headed “Tin-Vanadium Deposits, Tsitsutl Mountain Tin” with a footnote “Examined by H. W. Little, Geological Survey, 1942.” I can find no published reference to Little’s work, but this explains the reason for Minfile calling this a tin occurrence. The extended quote from Armstrong (1949, p. 194) is “During the field season of 1942, J. Pataji, a prospector in the employ of the Geological Survey, discovered a vein of rhodonite on the north slope of Tsitsutl Mountain in the Middle River Range. Spectroscopic analyses indicated manganese, tin, vanadium, and cobalt, and as a result a group of claims was staked in the autumn of 1942.” – by whom not stated, and there is no record in the Annual Reports of the Minister of Mines. As noted above for rhodonite, analyses by the British Columbia Department of Mines suggested that a sample of the rhodonite contained interesting levels of zinc and tin, but it is not clear whether this was a new analysis or simply relied on the original spectroscopic work. The work by the Bureau of Mines in Ottawa was described as an assay, but the precise process was not given. To add to the confusion, the work by Ellsworth of the Geological Survey of Canada (see note above for ilmenite) did not mention either tin or zinc. This demonstrates clearly the frustration of using published information, in this case more than 80 years old, to report on unusual mineral occurrences.
Giles Peatfield Comments on the Rock Types Reported:
These rock names were reported for the occurrence area by numerous workers. The names have been somewhat simplified – there are many varieties of most of the types.
Giles Peatfield
BASc. (Geological Engineering) University of British Columbia 1966.
PhD Queen's University at Kingston 1978.
Worked for Texas Gulf Sulphur / Texasgulf Inc. / Kidd Creek Mines - 1966 to 1985.
Consultant 1985 to 2016

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Link to British Columbia Minfile:	093K 042

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References