K showing, Lac Mistamisk, Nunavik, Nord-du-Québec, Québec, Canadai

Regional Level Types
K showing	Occurrence
Lac Mistamisk	- not defined -
Nunavik	- not defined -
Nord-du-Québec	Administrative Region
Québec	Province
Canada	Country

The K-showing uranium occurrence is located about 2 kilometres south-east of the south-east end of Lac Mistamisk and just south of the Romanet River. The showing is part of the Kish occurrence, one of two in the general area, the other being the Eagle, about 1.2 kilometres east of the lake and immediately south of the river. More generally, the area lies about 195 kilometres north-northwest of Schefferville, and 1,000 kilometres north of Québec City.

This Mindat posting will consider material from both the Kish and Eagle occurrences; the photos appended are of material from the K showing at the Kish occurrence. Note that there is an error in Kish and Cuney’s (1981) paper; on page 474 they reversed the locations of the ‘K’ and ‘B’ showings. ‘K’ is the Kish occurrence; ‘B’ the Eagle. Thanks to J. D. Scott for pointing this out and providing correspondence with Kish dated September and November 1982.

The following capsule description of the occurrences is quoted from the abstract of Kish and Cuney (1981):



Kish and Cuney (1981) discussed Uranium-lead ages for some material from the property, as follows:



Giles Peatfield comments on the minerals reported:

The mineralogy of the K-showing on the Kish property has several points of interest. I have chosen to comment on all minerals reported, a few in some detail. Almost all of the minerals listed were reported by Kish and Cuney (1981); a very few others and some varietal names were added by other workers.

Allanite: Kish and Cuney (1981) noted that “The argillite and silty rocks are schists or phyllites, composed of an assemblage of quartz, phengite, albite, minor chlorite, and accessory monazite and allanite characteristic of low-grade regional metamorphism.”

Altaite: Kish and Cuney (1981) noted that “Altaite (PbTe) occurs rimming melonite and rarely as independent grains.”

Ankerite: Béland (1976), describing vein material at the Eagle occurrence, reported that “The dominant mineral is a brownish ankeritic carbonate in large poikilitic crystals enclosing, with some corrosion, albite crystals, quartz grains, blades and sheaves of chlorite, some of it derived from biotite. It should be noted that biotite also occurs as unoriented crystalloblasts in the coarser laminae of the schists. The same minerals constitute the "matrix" between the large ankerite crystals.”

Apatite: Apatite (variety not stated) was not specifically reported from the K-showing. Clark and Wares (2005) reported it as an accessory at the Eagle occurrence about 2 kilometers to the south-east in similar geology. It may well occur at the K-showing as well.

Calcite: Kish and Cuney (1981), describing vein material, commented that “Calcite occurs as a late trace constituent.”

Chalcopyrite: Kish and Cuney (1981) commented that “Sulphides are rare and are usually associated with altaite - mostly small grains of chalcopyrite, pyrite, and galena.”

Chlorite group: Several workers reported “chlorite”. More particular information was provided by Kish and Cuney (1981), who wrote that “Chlorite makes up to 2-3 % of the vein material occurring as green to black crystals several millimetres long, generally coating albite combs before carbonate deposition... Locally chlorite occurs on the albitized wall rocks or enclosed in albite and carbonates. Analyses of chlorite ... indicate that the mineral is rich in magnesium ... The composition corresponds to sheridanite according to Hey (1954), ...” Sheridanite is now regarded as a synonym for clinochlore.

Clausthalite: Clausthalite was not specifically mentioned by Kish and Cuney (1981) except as a listing as a minor mineral in their “FIG. 3. Paragenesis of the Mistamisk veins.”

Covellite: Kish and Cuney (1981) commented that “Chalcopyrite is partly altered to covelline [sic - covellite].”

Dolomite: Kish and Cuney (1981) commented that “Dolomite constitutes about 10% of the vein material. It is coarsely crystalline, either filling voids between albite and uraninite crystals or fractures. The crystals are twinned, containing tiny crystals of hematite. Microprobe analyses of dolomite ... indicate that the iron content is positively correlated with manganese.” Query – is this possibly what Béland (1976) described as ankerite?

Feldspar group: Kish and Cuney (1981), describing the feldspar at the Kish occurrence, wrote that “Albite forms crystals up to 3 cm long, oriented randomly except at the margin of the veins where they are perpendicular to the contact ... The crystals show twin lamellae, displacement along microfractures and brecciation ... and are pink due to evenly distributed 1-5 µm hematite lamellae and to hematite coating cleavages and microfractures. Fine-grained white mica occurs in the albite, adjacent to the sericite schist wall rock. Carbonaceous inclusions with no birefringence or anisotropy and containing no uranium occur locally as rounded pods, several millimetres long ...”

Galena: See comment above for chalcopyrite.

Goethite: Kish and Cuney (1981), in their listing of minerals identified, wrote that “Goethite occurs as a fracture coating associated with hexavalent uranium minerals and is an alteration product.”

Gold: Kish and Cuney (1981) reported that “Native gold is present in tiny grains (300 to 400 µm) mostly in altaite and melonite...” Clark and Wares (2005) noted that gold occurs with tellurides at the Kish occurrence but did not report it at Eagle.

Hematite: All workers have reported hematite, usually reporting it as fine or dust, imparting a reddish colour to albite.

Melonite: Kish and Cuney (1981) reported that “Melonite (NiTe2) forms anhedral blebs or fills fractures in uraninite and albite or hairline cracks in the host rock ...” Refer to the polished section photo attached to this posting.

Mica group: There have been numerous mentions of minerals in the mica group on the property. Béland (1976) noted that at the Eagle occurrence “Both schists are composed of fine quartz grains, and some albite, held in a phylloblastic web of sericite mainly with some chlorite.” He also remarked that “It should be noted that biotite also occurs as unoriented crystalloblasts in the coarser laminae of the schists.” Kish and Cuney (1981) reported “white mica” and sericite, as well as phengite, a variety of muscovite – see note above for allanite. Clark and Wares (2005) mentioned phlogopite as an accessory mineral in the veins.

Molybdenite: Kish and Cuney (1981) listed molybdenite as a minor, late stage constituent of the vein material at Kish, but gave no further details.

Monazite: See comment above for allanite.

Pitchblende: In their description of the paragenesis of the minerals, Kish and Cuney (1981) wrote that “The third stage was a partial remobilization at a lower temperature, demonstrated by the double cell dimension in the uraninite crystal structure and the local occurrence of pitchblende veinlets.”

Pyrite: Bravoite, which is a Ni-bearing variety of pyrite, was not specifically mentioned by Kish and Cuney (1981) except as a listing as a minor mineral in their “FIG. 3. Paragenesis of the Mistamisk veins.” See comment above for chalcopyrite.

Quartz: Kish and Cuney (1981) reported that “Quartz occurs in the non-radioactive part of the K vein filling spaces between large albite laths: its relationship to uraninite is uncertain. Exceptionally it occurs in healed hair fractures in the radioactive part of the vein.” Clark and Wares (2005) reported light pink chert veins at the Eagle occurrence.

Tourmaline group: Béland (1976), describing schistose rocks at the Eagle occurrence, reported that “Tourmaline, pyrite, carbonate rhombohedra, and zircons have been observed in thin sections of both schists.” He gave no further data regarding specific mineralogy.

Uraninite: Kish and Cuney (1981) described the uraninite as follows: “Uranite is unevenly distributed, but is generally concentrated in the axial part of the vein forming masses of closely packed cm-size crystals, some with well-developed cubic faces ... The uraninite is fractured and recemented by albite and carbonate ..., so that it was among the first minerals to crystallize. Albite is sometimes included in uraninite. Yellow alteration products coat uraninite crystals and occur on fractures in uraninite, albite, and carbonate grains.” Note that several workers have mentioned yellow secondary uranium minerals, but no one has been more specific as regards to mineralogy. Kish and Cuney (1981), reporting on the paragenesis of the minerals, wrote that “Lastly a late-stage alteration produced yellow hexavalent uranium compounds, goethite and iron hydroxides.”

Zircon: Zircon was not specifically reported from the K-showing. Clark and Wares (2005) reported it as an accessory at the Eagle occurrence. It may well occur at the K-showing as well.

Giles Peatfield comments on the rock types reported:

The rock types listed, with one exception, were reported by Kish and Cuney (1981). Clark and Wares (2005) reported “mudrock” which I have interpreted as mudstone.

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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References