Alkaline Rocks and Carbonatites of the World

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Cariboo-Bell

stripes

Occurrence number: 
031-00-021
Country: 
Canada
Region: 
British Columbia
Location: 
Longitude: -121.58, Latitude: 52.58

Situated in the Quesnel Trough and emplaced in volcanics of Upper Triassic to Lower Jurassic age, Cariboo-Bell is a multiple laccolith covering some 25 km2. The volcanics include flows of either trachybasalt with abundant phenocrysts of augite and fewer of serpentinized olivine in a groundmass of augite, aegirine- augite, calcic andesine and orthoclase, or analcime trachybasalt in which some of the analcime occurs as phenocrysts up to 3 cm in diameter. The laccolith comprises six phases, five of which are concordant to each other and the country rocks, while the sixth is a partly discordant breccia. The upper northeastern part of the laccolith consists in order of emplacement of syenodiorite, monzonite porphyry, intrusion breccia and pyroxenite/gabbro. The lowermost unit of the laccolith is a mafic pseudoleucite syenite with 20% pseudoleucites up to 2 cm across, in a matrix of K- feldspar, albite, nepheline, aegirine-augite, amphibole and magnetite. This rock is in sharp contact with pseudoleucite syenite containing 30-90 % pseudoleucites which may attain diameters of 4 cm. Pseudoleucite is most abundant in the lowermost third and its variation defines a gross layering.

Economic: 
Six copper-rich zones have been defined, all adjacent to syenodiorite in the northeast of the complex. Reserves for two zones are 25 million tons grading 0.59% Cu and about 0.56% p.p.m. Au and 1.12 p.p.m. Ag.
Age: 
A K-Ar age on hydrothermal biotite gave 184+-7 Ma (J.Harakal, quoted in Hodgson et al., 1976, p. 393).
References: 
HODGSON, C.J., BAILES, R.J. and VERZOSA, R.S. 1976. Cariboo-Bell. In Porphyry copper deposaits of the Canadian Cordillera. Special Volume, Canadian Institute of Mining and Metallurgy, 15: 388-96
Fig. 15 Cariboo-Bell (after Hodgson et al., 1976, Fig. 2).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith