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Laura REE prospect (Laura prospect), Mount Bisson, Omineca Mining Division, British Columbia, Canadai

Regional Level Types
Laura REE prospect (Laura prospect)	Property
Mount Bisson	Mountain
Omineca Mining Division	Mining Division
British Columbia	Province
Canada	Country

The Laura REE prospect is located on Mount Bisson, 55 kilometres north-west of Mackenzie, British Columbia, in the Omineca Mining Division.
There is a brief description of the property on the British Columbia “Minfile” site, current to 2018, to which interested readers are referred. Relevant portions pertaining to geology are quoted below:
“The area lies within the Omineca Belt, which consists of siliciclastic sediments with minor carbonates and mafic rocks. These rocks belong to the Upper Proterozoic Ingenika Group. Within the Wolverine Range, the sediments are highly metamorphosed and subsequently intruded by granodioritic bodies and associated pegmatites, which are possibly Early Cretaceous. These high-grade metamorphic rocks, known as the Halleran Alkaline Complex, part of the Wolverine complex, consist of amphibolite and calc-silicate gneiss, schists, micaceous quartzite, and crystalline limestone. Metasomatism of the Wolverine amphibolite gneisses resulted in a secondary alkalic overprinting, possibly related to a deep-seated intrusion. Four rare earth element (REE) minerals have been found on the property, including monazite, allanite, cerorthite [see comment below for “allanite group”] and an unidentified Ba-Fe-REE-silicate.
The Laura showing occurs within a 110 by 60 metre zone of alkalic alteration. Monzonite (Mount Bisson intrusions) outcrops to the south. Biotite amphibolite appears to be altered to banded aegirine augite-alkali feldspar syenite. Within the alteration zone are various pegmatites containing allanite, nepheline, monazite, quartz, magnetite, and feldspar. The allanite pegmatites are up to 30 metres long and 4 metres wide.”

Giles Peatfield comments:
Laura is one of several similar REE occurrences in the immediate Mount Bisson area, discussed by Halleran (1991). Refer also to Minfile occurrences: URSA, MOUNT BISSON (Minfile No. 093O 041); and to WILL, WILL No.2, WILL No.1 (Minfile No. 093N 201). Pell (1994) provided a detailed summary of the geology and petrology in the Mount Bisson – Monroe Creek area, which includes Laura as well as the two other occurrences noted above. These are all small occurrences, of probably little economic importance but with interesting mineralogy.
There have been two radiometric dates published for metamorphic rocks of the Wolverine complex, reported in Tipper et al. (1974), who reported K/Ar ages of 69 Ma and 43 Ma for biotite. The dating was performed by the Geological Survey of Canada. I can find no information regarding radiometric dating for the mineralizing events

Giles Peatfield comments on the minerals reported:
The following comments, derived from several reports, give some details of the various minerals reported from the Laura prospect. Note that in many cases, there are additional data; full descriptions are beyond the scope of this review.
Allanite group: Halleran (1988) reported cerorthite. This mineral was re-named by the IMA in 1987 as allanite-(Ce). Halleran (1991) reported detailed microprobe data for allanites from the Laura area. A total of five representative samples from Laura gave a range of 9.29% to 12.67% Ce2O3 and 5.74% to 8.30% La2O3. These percentages are close to those given for allanite-(Ce) in the Handbook of Mineralogy (Anthony et al., 2001). Further speculation is beyond the scope of this review – suffice it to say that there is allanite in the Laura rocks.
Amphibole group: Halleran (1988) reported “hornblende”. Halleran (1991) identified several distinct varieties, listing: magnesio-hornblende; edenitic hornblende; magnesio hastingsite; and tremolite (as inclusions in aegirine-augite). For more detailed information, refer to Halleran’s 1991 MSc Thesis (UBC).
Apatite: This is common at Laura. Halleran (1991) provided some detailed analytical data; of interest here is that one of his samples from Laura was analyzed by microprobe, and found to have 5.63% SrO and 4.50% total RE2O3. This led him to call the mineral “saamite”, which is now incorrect as this mineral is not in fact a phosphate but rather a complex Ba Ti REE silicate (as of 2013, Back, 2022). What Halleran (1991) was probably seeing was “Saamite (of Volkova & Melentiev)”, a strontium-rich variety of fluorapatite (see Mindat Minerals, and refer to Volkova and Melentiev (1939) and to Palache, Berman and Frondel (1951) for more details). Note that this name for a variety of fluorapatite does not denote an IMA approved mineral species.
Chalcopyrite?: Leighton (1997) listed chalcopyrite and malachite in the legend of his detailed map of the Laura occurrence area. Unfortunately, the reproduction is so poor that the localities cannot be made out on the map, and there is no mention of either mineral in the text of the report. I would class both as tentative at this stage. Halleran (1988, 1991) reported chalcopyrite and malachite in an alkali-feldspar aegirine-augite syenite from the nearby Will occurrence; it seems possible that chalcopyrite and malachite are also present at Laura.
Chlorite group: Halleran (1988) reported minor amounts of “chlorite” in “banded aegirine-augite alkali-feldspar syenite” at Laura.
Epidote: Halleran and Russell (1993) reported small amounts of epidote in the “Pegmatites” devoid of significant REE concentrations . . . .”
Feldspar group: Most of the reports cited listed both plagioclase and potassium feldspar, but provide few details.
Hematite: Halleran (1988) reported hematite in “banded aegirine-augite alkali-feldspar syenite” at Laura.
Ilmenite: Halleran (1988) hematite in “banded aegirine-augite alkali-feldspar syenite” and in “nepheline syenite pegmatite” at Laura.
Magnetite: Halleran (1988) identified magnetite in “banded aegirine-augite alkali-feldspar syenite” at Laura.
Malachite?: See note above for chalcopyrite.
Mica group: Biotite is common, found in several rock types. It is the only mica specifically mentioned at Laura.
Monazite: Halleran (1988) reported several occurrences of monazite, although it is not clear that these were actually from the Laura area or all from the nearby Ursa occurrence. Unfortunately the maps are not included in the online version of this report. Halleran (1991) found a trace amount of monazite in a sample from the Laura area. Halleran and Russell (1993) reported monazite in the sample from the Laura area.
Nepheline: Halleran (1988, 1991) and Halleran and Russell (1993) reported small amounts of nepheline in REE-bearing pegmatites at Laura.
Pyroxene group: The most common member of the group at Laura is aegirine-augite; Halleran (1988, 1991) reported this in several rock types. Halleran (1991), describing the Laura and Will fenites, wrote that “Fenites are characterized by subhedral to anhedral, altered, light-blue-green to green aegirine-augite and augite containing small patchy zones of magnesio-hornblende (Laura #1) and subcalcic tremolite (Laura #2).” Halleran (1991) reported hedenbergite in syenite pegmatite from the nearby Will occurrence; it seems possible that the mineral also occurs at Laura.
Quartz: This is common here; mentioned in several reports.
Thorite: Traces of thorite were reported by Halleran (1991) and by Halleran and Russell (1993) in REE-bearing pegmatite.
Titanite: This is common at Laura. Halleran (1988) referred to the mineral as sphene. Halleran (1991) employed the name titanite, and provided some detailed analytical data.
Zircon: Halleran (1988) reported zircon in syenite and amphibolite. Halleran (1991) reported traces of zircon in REE-bearing pegmatites and in fenites at Laura.

Giles Peatfield comments on the rock types reported:
These rock names are derived from the several reports used in this review. Some may be alternate names for the same rock type, but I have chosen to list them all. Be aware that in most cases these are field names.

Other Databases

Link to British Columbia Minfile:	093O 021

Other Regions, Features and Areas containing this locality

References

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