Basque claims (Basque No. 1), Venables Valley, Ashcroft, Kamloops Mining Division, British Columbia, Canadai

Regional Level Types
Basque claims (Basque No. 1)	Group of Claims
Venables Valley	Valley
Ashcroft	Town
Kamloops Mining Division	Division
British Columbia	Province
Canada	Country

The Basque No. 1 evaporite occurrence is located in Venables Valley, 15 kilometres south-southwest of the village of Ashcroft, or about 72 kilometres west of Kamloops, British Columbia, in the Kamloops Mining Division. It is one of six evaporite ponds in a limited area of the Venables Valley, four of which (Basque No. 1 to No. 4) are British Columbia “Minfile” sites. A fifth (Basque No. 5) and sixth (Basque West) are nearby. A note of explanation is required. The present Mindat site is “Basque claims, Venables Valley, Ashcroft, Kamloops Mining Division, British Columbia, Canada. I (Giles Peatfield) have chosen to add “Basque No. 1” to the name, because the detailed position shown on the present Mindat site is for that occurrence, and there are three other Basque evaporite occurrences with separate British Columbia “Minfile” numbers, as well as two more without. I have prepared separate Mindat files for all of these occurrences, as they have slightly different characteristics. For more detail on the Basque area evaporites, refer to Goudge (1926), Cummings (1940) and Duffell and McTaggart (1952). Of some historical interest is the early paper on the deposits by Walker (1921).
There is a detailed description of the geological setting for this occurrence on the British Columbia “Minfile” site, current to 2007. A portion of this description is quoted below:
“The Basque salt deposits occur in four [see comment above] small basins or mud-filled ponds 2 kilometres west of Highway 1 and 15 kilometres south of the community of Ashcroft. . . . . The distance between the Basque No. 1 deposit in the north to the Basque No. 4 deposit in the south is about 1524 metres. The salts have accumulated in four small ponds that lie along a dry valley and are concentrated mainly in the two upper ponds (Basque Nos. 1, 2). Overburden is light or lacking, and in many places bare rock walls form part of the border of the ponds. These ponds are caused by dams of boulder clay and drift that cross the narrow valley.
A sequence of highly folded, metamorphosed, interbedded and nearly vertical dipping greenstone, argillite and argillaceous limestone of the Carboniferous to Jurassic Cache Creek Complex are exposed in the vicinity of the deposits. The Cache Creek rocks strike about 170 degrees.
The Basque deposits are hydrous salts of magnesium, sodium and calcium and consist primarily of mixed hydrous magnesium sulphate (epsomite or Epsom salt) and hydrous sodium magnesium sulphate [sic] (bloedite) [sic blödite], as well as hydrous sodium sulphate (mirabilite or Glauber's salt). The top one metre in all of the deposits is principally epsomite. Mirabilite generally occurs near the surface and the bloedite at depth. There are also small amounts of calcium sulphate, sodium bicarbonate and sodium chloride present [see comment below]. Potassium in small amounts has been determined in the brines.”
Giles Peatfield comments:
There is much additional information in the Minfile report, to which interested readers are referred. Much of this is derived from the work of Goudge (1926) and of Cummings (1940). There are no references that I can find of identification of “calcium sulphate, sodium bicarbonate and sodium chloride” present as recognized minerals. For example, Duffell and McTaggart (1952) referred to “. . . minor amounts of other soluble salts.” These salts were listed by Goudge (1926) in his ‘analyses of crystal’ from the Basque No. 1 deposit, but it is not clear whether he actually identified the minerals or simply assumed from the analyses that they should be present.
Official records of production from Basque No. 1 (see “Minfile”) show that between 1918 and 1942, a total of 7,634 tons (6,926 tonnes) of material was mined, with production of 5,352,000 kilograms of what was described as “Magnesium Sulphate”.
Comment on Minerals Reported:
Blödite: This was reported by Goudge (1926), by Cummings (1940), and by Duffell and McTaggart (1952). Renaut and Stead (1994) reported blödite but gave no analytical data; presumably they based their identification on earlier workers.
Dolomite: This was reported as “protodolomite” by Renaut and Stead (1994), presumably basing this on work by Nesbitt (1990) at the Basque No. 2 occurrence. Nesbitt described “protodolomite” as having a variable composition. He commented that in the X-ray analysis “Super-structure peaks have not been observed, suggesting that the protodolomite is essentially disordered and may best be assigned to the . . . space group (calcite structure) rather than the . . . space group of ordered dolomite.”
Epsomite: This was reported by Goudge (1926), by Cummings (1940) and by Duffell and McTaggart (1952). Peterson et al. (2007) identified epsomite by X-ray diffraction analysis.
Gypsum: Reported by Renaut and Stead (1994) but with no information regarding the method of identification.
Ice: Reported by Peterson et al. (2007), who were collecting in winter conditions.
Magnesite: Reported by Renaut and Stead (1994) but with no information regarding the method of identification.
Meridianiite: This is the mineral of specific interest, for which this is the type locality. Peterson et al. (2007) gave a detailed explanation of the formation and analysis of this extremely uncommon mineral; their paper can be accessed using the link provided in the comment on the second photograph.
Mirabilite: Reported by Renaut and Stead (1994) but with no information regarding the method of identification. Interestingly, Peterson et al. (2007) made the point that mirabilite was not present in their samples, but this may have to do with the time of collection (winter as opposed to summer).
Thénardite: Peterson et al. (2007) identified thénardite by X-ray diffraction analysis.
Comment on Rock types Reported:
The rocks listed here are for the immediately surrounding area, as reported by Goudge (1926), or in the case of volcanic ash by Nesbitt (1990), who described this as 6,000 year old Mazama ash. This is common in southern British Columbia. Nesbitt’s report of volcanic ash refers to the entire group of occurrences, not just to Basque No. 2.

Other Databases

Link to British Columbia Minfile:	092INW043

Other Regions, Features and Areas containing this locality

References