Upper Arrow Lake uvarovite occurrence, Nakusp Area, Slocan Mining Division, British Columbia, Canadai

Regional Level Types
Upper Arrow Lake uvarovite occurrence	Occurrence
Nakusp Area	- not defined -
Slocan Mining Division	Division
British Columbia	Province
Canada	Country

The location of this occurrence is not certain. The description in Hoffmann (1903) is as follows: “Uvarovite. This variety of garnet has been observed in a sample of material, which was sent to the Survey for examination, from near the southern end of Upper Arrow lake, on the west side, and between Despatch [sic – Dispatch] island and point opposite Nakusp, - on the east side of the lake, in the West Kootenay district of the province of British Columbia.” An approximate location has been estimated as:
Latitude 050º 12' North; Longitude: 117º 50' West.
The locality is in the Slocan Mining Division, British Columbia.
Further points of interest are that the Dispatch Island[s] were named for the river steamboat “Dispatch”, which plied the Columbia River as far north as Revelstoke (Wikipedia – Steamboats of the Arrow Lakes; also Turner, 1984). Also note that the water level of the lake was raised, at least at high water time, after the construction of the Keenleyside Dam near Castlegar in 1968 (Wikipedia – Keenleyside Dam), so the original locality, if it was in fact at lakeshore, may well now be submerged.
There is very little detailed geological information for this site, given its rather uncertain location. The legendary Canadian geologist G. M. Dawson of the Geological Survey of Canada passed down-river from Revelstoke, but unfortunately his attention was drawn to the eastern side of Upper Arrow Lake and he did not examine the western shore (Dawson, 1890, p. 37B). Hyndman (1968) mapped the region, including the area of interest here. He included all this area in his “Monashee Group Undivided: pelitic schist, paragneiss, pegmatite; . . . .” of “Paleozoic And (?) Earlier” age. In terms of metamorphic facies, he included most of the west shore of the lake south of Nakusp in his “Staurolite-almandine subfacies” of the “Almandine-Amphibolite Facies”. It is interesting to note that nowhere in this area did Hyndman describe any rocks that might have provided a source for the Cr in the uvarovite.
As an aside: George Mercer Dawson is a legend in Canadian geology. Explorer, geologist, anthropologist, writer, poet, artist, he had two cities (Dawson Creek, British Columbia and Dawson City, Yukon named for him. At the time of his death in 1901 he was Director of the Geological Survey of Canada. For more on Dawson, interested readers will find much information in Zaslow (1975) and in a “memoir” by Jenkins (2007), based on a compilation of Dawson’s correspondence, diaries, etc.

Giles Peatfield's comments on reported minerals:
Garnet group: This is the mineral of main interest at this site. It was originally reported by Hoffmann (1903) as uvarovite. Johnston (1915) listed “uvarovite (garnet)” from “Upper Arrow lake.” Traill (1970; 1983) demurred, noting that “The name has been loosely applied to chromian garnet, especially chromian grossular, and the Canadian minerals below are probably that species rather than uvarovite.” All the minerals listed by Traill were from Québec. Finally, Dunn (1978) analyzed several Canadian green garnets, using an ARL-SEMQ electron microprobe. Most of these turned out to be chromian grossular, but two, one from “South Ham, Wolfe County, Quebec” and a second from “Upper Arrow Lake, West Kootenay District, British Columbia [GSC # 14671]” are indeed uvarovite. According to Dunn, the Arrow Lake mineral contains 15.69 percent Cr2O3.
Graphite: Hoffmann (1903) described, in his specimen, “a few scales of graphite.”
Magnetite: Hoffmann (1903) mentioned “particles” of magnetite.
‘Pyroxene’: Hoffmann (1903) described small quantities of “gray, grayish-green, and grayish-brown pyroxene” but gave no specific data.
Pyrrhotite: Hoffmann (1903) mentioned “particles” of pyrrhotite.
Quartz: Hoffmann (1903) described “white, translucent quartz.”
Scapolite: Hoffmann (1903) described “white scapolite.”

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.
Vancouver based consultant 1982 to retirement in 2016.
Presently totally retired and happily living in Courtenay, B.C. (Vancouver Island) - preparing postings for Mindat, mostly on B.C. deposits / occurrences.

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References