Great Gull Scheelite prospects, Great Gull Lake, Newfoundland, Newfoundland and Labrador, Canadai

Regional Level Types
Great Gull Scheelite prospects	Prospect
Great Gull Lake	Lake
Newfoundland	Region
Newfoundland and Labrador	Province
Canada	Country

The Great Gull Scheelite prospects (South Quarry and Camp Ten) are located on the Bay D’Espoir Highway (Highway 360) in central Newfoundland. More specifically, it lies about 12.5 kilometres south-west of Great Gull Lake, and 86 kilometres south of Bishop’s Falls.

The Great Gull tungsten property hosts two separate, distinctly different scheelite occurrences about four kilometres apart. At the South Quarry prospect, scheelite occurs as large (up to 2 centimetres) equant crystals, in pegmatitic quartz-feldspar veins, in what Robertson and McLean describe as metagraywacke and metalimestone with interbedded schists. To the south, the Camp Ten prospect has metagraywacke and phyllite with thin beds of calc-silicate rock with scheelite and clinozoisite amongst other minerals. For more details, refer to Robertson and McLean (1991). Note that for convenience the pegmatitic quartz-feldspar veins will be referred to herein as pegmatite veins.

Robertson (1984) wrote that the Middle Ridge Granite pluton, exposed immediately east of the claim block, yielded a Rb-Sr age (re-calculated using up-dated decay constant for 87Rb) of 383±15 Ma. Robertson and McClean (1991), quoting Olshefsky (1984), wrote that the scheelite-bearing veins were dated at 374±13 Ma.

Giles Peatfield comments on the minerals reported:
The mineralogy of the Great Gull property has several points of interest. I have chosen to comment on all minerals reported, a few in some detail.
Amphibole group: Olshefsky (1984) and Robertson and McLean (1991) refer to the amphibole as actinolite.
Arsenopyrite: Robertson (1984) mentions arsenopyrite as a minor constituent of the pegmatite veins at South Quarry.
Bavenite: Dr. J. D. Scott, in an email dated 27 February 2024, informed me that a specimen was sent to CANMET in Ottawa, analyst J.H.G. Laflamme. Scott’s “. . . post X-ray mineral notes were: GG83-15B: bavenite (bladed pearly crystal plates), roggianite (radial white fibrous), beryl in quartz pegmatite.  South Quarry, Great Gull Lake, Newfoundland.” Bavenite is not a commonly reported mineral in Canada; Mindat has only two localities presently listed for the country.
Bertrandite?: Dr. J. D. Scott, in an email dated 26 February 2024, informed me that “I also have two chips in a vial labelled Bertrandite? Great Gull Lake, Nfld.” This material has not been X-rayed at this time, but is slated for examination.
Beryl: Robertson (1984) mentions beryl as a minor constituent of the pegmatite veins at South Quarry. One crystal, in my collection, with grey quartz and coarse mica (muscovite?) measures 5 centimetres in maximum dimension (see attached photo). Dr. J. D. Scott, in an email dated 28 February 2024, provided the following interesting information: “Given the fact that somewhat weathered beryl (as shown by the weakly-corroded crystals in both of our specimens) also occurs at the South Quarry, it should perhaps be noted as being the probable source for the beryllium for the rare minerals observed. If you want to get more specific, both the bavenite and the roggianite seem to have grown in a late fracture in milky (not smoky) quartz that intersected a corroded beryl crystal; thus probably making them of hydrothermal origin.”
Calcite: This is minor mineral at South Quarry, and is ubiquitous at Camp Ten.
Chlorite group: Robertson and McLean (1991) reported chlorite from drill core at Camp Ten, but gave no more specific data. See note below for Mica group.
Clinozoisite: This was reported by Olshefsky (1984) in rare lenses of clinozoisite-actinotite in the host metasedimentary rocks.
Feldspar group: Robertson and McLean (1991) reported that the pegmatite veins at South Quarry contain both plagioclase and K-feldspar, but were not more specific. Dr. J. D. Scott, in an email dated 28 February 2024, informed me that “Also, I am quite sure that the large feldspar-crystal section noted in my scheelite specimen description is in fact albite, not just plagioclase and the large-flake mica is definitely muscovite and not phlogopite.”
Fluorite: Robertson and McLean (1991) reported that fluorite is a minor constituent of the pegmatite veins at South Quarry.
Garnet group: Robertson and McLean (1991) wrote that “Porphyroblasts of garnet are common in the greywacke . . . .” They gave no specific data regarding the garnets. Kohlsmith (1985) noted porphyroblasts of garnet in thin sections from drill core at Camp Ten, but again gave no specific information.
Ilmenite?: Kohlsmith (1985) noted an opaque mineral in thin sections from Camp Ten drill core that he suspected might be ilmenite.
Mica group: Robertson (1984) reported muscovite from the pegmatite veins. Olshefsky (1984) reported mica in schistose country rocks, but did not specify a species. See also note above for Feldspar group. Kohlsmith (1985) based on examination of thin sections of Camp Ten drill core, reported that “Chlorite and biotite are common constituents of calc-silicate horizons.”
Natrolite: Robertson and McLean (1991) reported that natrolite is a minor constituent of the pegmatite veins at South Quarry.
Pyrite: Robertson and McLean (1991) reported that pyrite is a minor constituent of the pegmatite veins at South Quarry.
Pyrrhotite: Robertson and McLean (1991) reported that pyrrhotite is a minor constituent of the pegmatite veins at South Quarry.
Roggianite: See the note above for bavenite. Roggianite is a rare mineral; Mindat at present lists a locality in Italy and a second in Russia; this is the first for Canada and the third world-wide.
Quartz: This is common, especially in the pegmatite veins at South Quarry. As noted above, my specimen of beryl has a pale grey quartz mass attached. Dr. J. D. Scott, in an email dated 27 February 2024, informed me that he has a specimen of quartz from South Quarry. He wrote that “The quartz is definitely smoky, some of it with rather odd lighter bands that look almost like gel-precipitated material.” These particular quartz specimens are both from pegmatite veins. Quartz from elsewhere on the property is clear or white. The subject would benefit from further examination.
Scheelite: This is the mineral of principal economic interest at the Great Gull property. Scheelite occurs in the pegmatite veins at South Quarry as large (up to 2 centimetres) equant crystals, often with associated muscovite (see attached photo). It also occurs finely disseminated in thin calc-silicate bands in metasedimentary rocks at the Camp Ten locality.
Titanite: Robertson and McLean (1991) reported that sphene is a significant constituent of the calc-silicate bands at the Camp Ten prospect.
Tourmaline group: Robertson and McLean (1991) reported tourmaline as a minor constituent of the pegmatite veins at South Quarry. Robertson (1984) noted that mapping in the South Quarry area also identified a quartz-feldspar-tourmaline schist, probably derived from siltstone.
Wolframite: Robertson (1984) reported trace amounts of “wolframite” in the pegmatite veins at South Quarry, but did not say where in the ferberite-hübnerite series its composition might lie.
Giles Peatfield comments on the rock types reported:
The rock types listed, with exception of limestone, were reported by Robertson (1984). Note that Robertson and McLean refer to “metagraywacke” and “metalimestone”. Pegmatite refers to the quartz-feldspar-scheelite-beryl veins at South Quarry.

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