Rock Canyon Creek (Deep Purple) Fluorite-REE deposit, Canal Flats, Golden Mining Division, British Columbia, Canadai

Regional Level Types
Rock Canyon Creek (Deep Purple) Fluorite-REE deposit	Group of Claims
Canal Flats	Village
Golden Mining Division	Division
British Columbia	Province
Canada	Country

Latitude 050º 12' 25'' North; Longitude: 115º 08' 13'' West. The Rock Canyon Creek (Deep Purple) Fluorite-REE deposit lies in the valley of “Candy Creek”, a tributary of Rock Canyon Creek, about 48 kilometres east of the Village of Canal Flats, 176 kilometres south-east of Golden and 90 kilometres north-northeast of Cranbrook, British Columbia.
Note that the co-ordinates given above differ slightly from those given by British Columbia Minfile. These revised values are derived by reference to details given by Graf (1986). Rock Canyon Creek is an official gazetted geographic name; the tributary Candy Creek is an unofficial local name. It is important to note that this deposit is in no way related to the well-known Rock Candy fluorite mine near Grand Forks, British Columbia, some 250 kilometres to the west.
Giles Peatfield comments:
There is a brief description of the occurrence on the British Columbia “Minfile” site, current to 2018. Relevant portions of this description are quoted below:
“The area is underlain by a Cambro-Ordovician to Middle Devonian carbonate-dominated sequence. A west- dipping thrust fault places Cambrian and Ordovician strata over younger rocks. An overturned to upright homoclinal sequence, younging to the east, comprises coral-rich limestones of the Middle Ordovician-Silurian Beaverfoot Formation, unconformably overlain by dolomites, mudstone and solution breccias of the "basal Devonian unit", which are themselves conformably overlain by limestone of the Upper Devonian Fairholme Group.
Fluorspar and rare-earth mineralization is stratabound, hosted mainly by the "basal Devonian unit", and occurs in a northwest trend over 3.5 kilometres. The main type of fluorite mineralization identified consists of disseminations and veinlets of dark purple fluorite in a dolomite matrix. Associated minerals and elements include bastnaesite, pyrite, gorceixite, calcite, limonite, illite, barite, parisite, apatite, niobium, strontium and yttrium. Fluorite content generally varies from 2 per cent to greater than 10 per cent of the rock. Other types of occurring fluorite include: 1) higher grade, massive, fine-grained purple and white fluorite; 2) disseminated purple fluorite in white calcite, locally interbedded with dolomite and forming the matrix of solution breccias; and 3) massive purple fluorite in the matrix of an intraformational conglomerate.
A carbonatite-related origin is suggested for the fluorite and rare-earth mineralization, resulting from metasomatically altered (fenitized) Devonian carbonate rocks, possibly related to a deep-seated alkaline intrusion (Fieldwork 1988).”
There is much additional information in the published record, and several minerals present that are not listed in the quoted summary. Interested readers are referred to papers by, inter alia: Akam et al. (2019); Araoka et al. (2022); Paradis and Simandl (2019); Pell (1992); Pell and Hora (1987); and Simandl et al. (2022). Minerals are treated in much more detail in the next section of this summary.
Giles Peatfield Comments on the Minerals Reported:
Note: This deposit contains a number of less common minerals and some complex relationships. It is considered appropriate to add detailed comments for several of these species.
Allanite: Graf (1986) mentioned “allanite” in an “XRD spectrographic analysis” of two heavy mineral concentrates from Candy and Canyon [Rock Canyon?] creeks.
Anatase: McLeod (1986) described a fluorite-bearing rock in which “In reflected light disseminated, euhedral pyrite in grains from 0.02 to 0.2mm is abundant. Also prevalent is a grey reflective phase that turns out to be anatase. The titanium mineral rarely exceeds 0.2mm but is often abundant in grains of very fine size.”
Aragonite: Pighin (2010) described a dolomitic siltstone with “Scattered, thin veinlets (2 mm to 4 mm thick) of aragonite (very strong yellow fluorescence).”
Baryte: Several workers reported “barite”; Hoshino et al. (2017) confirmed the mineral by X-ray diffraction analysis. The mineral seems to be ubiquitous here, generally associated with pyrite and fluorite.
Bastnäsite-(Ce): “Bastnäsite” has been reported by numerous workers. Graf (1986) stated that it was confirmed by X-ray diffraction analysis (powder diffractometry – see Hora and Kwong (1986)). Hoshino et al. (2017) identified it by powder-XRD and SEM-EDS analyses, and designated it as bastnäsite-(Ce), noting that specimens had variable REE contents; for details refer to Table 3 in their paper.
Calcite: Reported by several workers. Hoshino et al. (2017) describe multiple examples of late-stage calcite veins.
Canfieldite, var. tellurium-bearing: Mueller (1986) wrote that “The heavy liquid concentrate [from a crushed rock with fluorite and prosopite] was examined with the microprobe to determine the silver mineralization. The initial qualitative microprobe examination indicated a unique chemical composition which warranted further quantitative microprobe examination.”
“The quantitative microprobe examination showed a major silver phase containing silver, tin, tellurium and sulfur.”
The microprobe results suggested a composition of Ag8Sn(TeS2)2. The thought at that time was that this was a new mineral, but there is no evidence that this was in fact followed up in any detail. Samson et al. (2001) mentioned this work but gave no further data.
There is a long history of publication regarding this phase. In this note, I shall be focusing on the relative contents of sulfur and tellurium.
Harris and Owens (1971) described a “tellurium-bearing canfieldite” from near Revelstoke, British Columbia, which they analyzed by electron microprobe and quoted 8.69 wt.% Te and 13.95 wt.% S. This was the Snowflake deposit – see Mindat occurrence “Snowflake Mine, Mount Cotterell, Revelstoke Mining Division, British Columbia, Canada.” This was in the form of a fine-grained intergrowth with argyrodite, and the authors made the point that the “. . . the accuracy of the analysis is questionable.” This analysis has been quoted by subsequent writers, but without the caveat. In the same year, Onteyev et al. (1971) reported “First find of tellurium canfieldite” from Belukhinskoye, USSR.
Subsequent workers (see, e.g., Kikutchi et al. 1980; Mariko 1981; Soeda et al. 1984; Brodtkorb 2002; and Bindi et al. 2012) listed analyses for this phase, ranging from 17.90 to 20.23 wt.% Te and 8.04 to 9.50 wt.% S. Mindat lists a mineral designated as ‘Tellurium-bearing canfieldite’. The Rock Canyon Creek analysis (Mueller, 1986) is close, although the S content is very slightly higher than the average. The other interesting feature is the provenance – none of the papers cited suggests that the other examples of this phase are found in a REE-F environment.
Cerussite: This was reported by Samson et al. (2001), who wrote that “Rare sphalerite and galena occur in patches with quartz, fluorite, cerussite and smithsonite, as a replacement of dolostone, and overprint calcite-fluorite-quartz veins.”
Crandallite group: Samson et al. (2001) described “crandallite-group” minerals as follows: “The crandallite group minerals belong to the crandallite-goyazite-florencite solid solution . . . . At Rock Canyon Creek, these minerals occur in veinlets. The porous texture and variable chemical composition suggest that the crandallite group minerals probably formed by relatively low-temperature hydrothermal, possibly retrograde, processes.”
Cryolite: Reported, in float boulders, by Samson et al. (2001), and by Green et al. (2017), who noted that “Cryolite, prosopite, and elpasolite have been observed in rounded and sub-rounded float boulders near the deposit . . . . However, these minerals have not been found in samples collected from outcrops and drill core. These boulders may either indicate undiscovered mineralization on the property, or they may have been derived from as far as the Ice River complex and transported by glaciation. The second explanation is less likely because Spectrum Mining Corporation failed to locate boulders with similar characteristics in drainages north of Rock Canyon Creek and south of the Ice River complex.” Paradis and Simandl (2019) added to the uncertainty, writing that “The source of boulders of massive fluorite-REE mineralization containing aluminofluoride minerals at Rock Canyon Creek (Zhu, 2000; Samson et al., 2001) remains enigmatic, but points to an affiliation with alkaline rocks. Geographically, the source of these boulders should be up ice (i.e. north-northwest).” The jury is out, but I would personally not agree with the concept of bringing this material from the Ice River Complex, almost 150 kilometres to the north-west.
Dolomite: This is major constituent of the host rocks of the occurrence. Hoshino et al. (2017) confirmed dolomite by both powder-XRD and SEM-EDS analyses. Zhu (2000) recognized several varieties of dolomite, including one that was described as “ferroan”.
Elpasolite: See note above for cryolite.
Feldspar group: “K-feldspar” was reported by, inter alia, Graf (1986), Hora and Kwong (1986), Samson et al. (2001) and Paradis et al. (2022). Hoshino et al. (2017) reported that the species was microcline.
Fluorapatite: Reported (as apatite) by Graf (1986) in heavy mineral concentrates; as traces by McLeod (1986); by Samson et al. (2001); and by Hoshino et al. (2017), who identified it by X-ray means and called it fluorapatite.
Fluorite: This is one of the main minerals of interest at this occurrence, reported by all workers. Most material is purple, but white fluorite was reported by Graf (1986). Hoshino et al. (2017) confirmed fluorite by both powder-XRD and SEM-EDS analyses.
Galena: This was reported by Samson et al. (2001) – see comment above for cerussite.
Gorceixite: Graf (1986) wrote that “An XRD study was done on 7 rock samples and 2 heavy mineral stream sediment samples collected in 1985. This work identified the REE-bearing minerals, bastnaesite and gorceixite, . . . .” This comment was probably based on the report of Hora and Kwong (1986), who noted that the mineral was, amongst others, confirmed by the powder diffraction method.
Goyazite: McLeod (1986) tentatively identified goyazite rather than gorceixite, based on petrographic examination of polished thin sections. Samson et al. (2001) identified goyazite in the float boulders (see note above for cryolite) – it is not clear from their paper what method was used to positively identify the mineral.
Graphite: Pighin (2010) mentioned a few cases of small amounts of graphite in drill core. In one case, he described “one dime-sized patch graphite**”, with the footnote “**1089 Mo ppm, 54 ppm W.” There are no mentions of molybdenite in the drill logs, and listed geochemical analyses of drill core for Mo are all low – the maximum value listed being 322 ppm, with W values all negligible. The high numbers shown above for this one sample are not given in the attached analytical sheets. There is a conundrum here that cannot be easily solved – the reader must make a personal judgement as to whether or not molybdenite is present.
Gypsum: Pighin (2010) described “. . . scattered, small crystals of selenite . . . in the silty limestone beds.”
Hematite: Hoshino et al. (2017) wrote that “Most of the pyrite in weathered surface samples is replaced by hematite.”
Illite: Green et al. (2017) listed illite as occurring in float material, citing the XRD work by Hora and Kwong (1986).
Jasper: Pighin (2010) described jasper as a minor alteration product in drill core of dolomitic limestone..
Kaolinite: Trace amounts of kaolinite were observed in XRD analyses, by Hora and Kwong (1986).
Limonite: This is common, generally as an alteration product of pyrite. McLeod (1986) described it in thin and polished thin sections.
Magnetite: This was listed by Green et al. (2017), citing the work of Pell (1992), who noted that “Massive purple fluorite, which constitutes greater than 20 per cent of the rock, forms the matrix of an intraformational breccia and locally replaces the fragments . . . . Minor barite, pyrite and magnetite are also associated with this type of mineralization.”
Monazite-(Ce): Listed by Green et al. (2017) as occurring in in-situ ‘ore’, citing the work of Hoshino et al. (2017), who identified it by SEM-EDS analysis, and determined that it was the Ce variety.
Muscovite: Samson et al. (2001) reported muscovite in float boulders with abundant fluorite and several other minerals (e.g. quartz, baryte, cryolite, prosopite, elpasolite and goyazite), in the southern portion of the property.
Parisite-(Ce): Pell and Fontaine (1989) noted that “Parisite [CaCe2(C03)3F2] has also been identified from fluorite veins with scanning electron microscopy, and may be associated with bastnaesite.” Hoshino et al. (2017) confirmed the identity by SEM-EDS analysis, and determined that it is the Ce variety.
Prosopite: Listed by Green et al. (2017) as occurring in the gangue of float material, citing the work of Hora and Kwong (1986) and Samson et al. (2001). See note above for cryolite.
Pyrite: This is ubiquitous and mentioned by all workers. It is one of the many minerals identified by Hoshino et al. (2017) by SEM-EDS analysis.
Pyrochlore: Listed by Green et al. (2017) as occurring in in-situ ‘ore’, citing the work of Samson et al. (2001).
Quartz: This has been identified in thin section (McLeod, 1986) and in drill core by Pighin (2010). It is one of the many minerals identified by Hoshino et al. (2017) by SEM-EDS analysis.
Rutile: Reported by Hora and Kwong (1986) as a minor constituent of a sample of “Fine-grained purplish grey massive fluorite with abundant pyrite.” Listed by Green et al. (2017) as occurring in in-situ gangue material, citing Samson et al. (2001).
Scapolite?: Pighin (2010) noted minor amounts of scapolite in drill core, but gave no analytical data. No other workers reported the mineral, and I would regard it as tentative.
Sericite: Pighin (2010) note small amounts of sericite in the matrix of quartzite.
Smithsonite: This was reported by Samson et al. (2001) – see comment above for cerussite.
Sphalerite: This was reported by Samson et al. (2001) – see comment above for cerussite.
Synchysite-(Ce): Listed by Green et al. (2017) as occurring in in-situ ‘ore’, citing the work of Samson et al. (2001). Hoshino et al. (2017) confirmed the identity by SEM-EDS analysis, and determined that it is the Ce variety.
Talc?: Hora and Kwong (1986) listed talc as a possible constituent of some dolomites.
Vivianite?: Pighin (2010) reported that “Widely scattered, paper thin fractures are lined by a powdery calcite and light blue vivianite . . . .”, but gave no analytical data. The mineral was not reported by any other worker.
Giles Peatfield Comments on the Rock Types Reported:
The rock types listed above (except gypsum) were reported by Pighin (2010), in drill core. Gypsum was described as calcareous (Green et al. 2017) or as silty calcareous (Paradis et al. 2022).

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:	082JSW018

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References