Alkaline Rocks and Carbonatites of the World

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Argor (James Bay Pyrochlore Deposit; Alpha-B Deposit; Southbluff Creek; James Bay Lowlands-North)

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Occurrence number: 
031-00-059
Country: 
Canada
Region: 
Ontario
Location: 
Longitude: -81, Latitude: 50.07

The Argor body is an elongate intrusion of pyroxenite and carbonatite about 2.5 km long, although the ends were not reached in drilling, with a maximum width of 300 m. It is emplaced into garnet-hornblende-plagioclase gneisses and augen gneisses but is overlain by 13-35 m of Lower Devonian sedimentary rocks of the Sextant Formation. The carbonatite is a complex body of several phases, the principal type comprising 60-68% dolomite, 5-10% riebeckite, 5-15% apatite, 5-10% phlogopite and 2-15% titaniferous magnetite, together with pyrochlore and zircon. Another carbonatite phase forms bands up to 6 m thick consisting of calcite with some apatite and phlogopite; olivine-bearing carbonatite is also present. Pyroxenite appears to have been intruded before the carbonatite and is principally found to the west of it. The pyroxenite consists of augite, salite, with amphibole, sometimes after pyroxene, biotite, and accessory sphene, apatite, titaniferous magnetite and sulphides, including pyrite, pyrrhotine and chalcopyrite.

Economic: 
Large quantities of pyrochlore have been proved by extensive drilling with 62.5 million tons averaging 0.52% Nb2O5.
Age: 
1635 Ma by K-Ar on biotite (Gittins et al., 1967 - 'James Bay Lowlands (North)').
References: 
FERGUSON, S.A. 1971. Columbium (niobium) deposits of Ontario. Mineral Resources Circular, Ontario Department of Mines and Northern Affairs, 14: 1-58. J.Gittins, personal communication, 1984; GITTINS, J., MACINTYRE, R.M. and YORK, D. 1967. The ages of carbonatite complexes in eastern Canada. Canadian Journal of Earth Sciences, 4: 651-5. STOCKFORD, H.R. 1972. The James Bay pyrochlore deposit. Canadian Mining and Metallurgical Bulletin, 65(722): 61-9
Fig. 31 Argor (after Stockford, 1972, p. 64).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith