Mount Edziza
This is the largest (65x24 km) and most complex of a group of late Tertiary and Quaternary volcanoes that lie along a north- south zone of normal faults on the eastern side of the coast geanticline in northwest British Columbia.
Canadian occurrences of alkaline rocks have previously been listed and described in some detail in the monograph by Currie (1976a), although a significant number that have come to light since that publication will be found here. These new localities notably include extensive areas of peralkaline granites in Newfoundland, and of alkaline volcanics and intrusives in British Columbia, and it seems likely that many future discoveries will be concentrated in the latter area.
Many of the more northerly carbonatite occurrences are only poorly known and have not been dated. Although generally badly exposed, many have been drilled but rarely have findings been published. Many Canadian occurrences have been investigated for their economic potential (see, for instance, Ferguson, 1971) and important mining operations for nepheline syenite at Blue Mountain and Nb at St-Honore are taking place, with active exploration and appraisal for phosphate and vermiculite elsewhere. A number of occurrences in Ontario is described by Parsons (1961) and nearly 30 Ontario carbonatites have recently been re-investigated by R.P. Sage, although his internal reports were not available when the present accounts were compiled. K-Ar ages on numerous carbonatites in eastern Canada are given by Gittins et al.(1967) and of a broader range of alkaline rocks by Doig and Barton (1968). Rb-Sr ages and Sr isotopic ratios for many Ontario occurrences have been published by Bell et al. (1982).
This is the largest (65x24 km) and most complex of a group of late Tertiary and Quaternary volcanoes that lie along a north- south zone of normal faults on the eastern side of the coast geanticline in northwest British Columbia.
Situated at the headwaters of Galore Creek, a tributary of the Scud River, the area consists of a sequence of moderately to intensely altered volcanic rocks which have been intruded by a number of syenites.
A long, narrow complex 6-700 m in length with a maximum width of about 50 m, lies conformably amongst schists and gneisses of the Wolverine complex, which are fenitized close to the complex. Carbonatite occurs as sodic pyroxene and biotite-rich types; in both the carbonate is calcite.
Goosly Lake is an approximately square-shaped stock of about 3x3 km which cuts early Mesozoic lavas and pyroclastic rocks. The rocks of the stock vary from gabbro to syenomonzonitic varieties. The former consist essentially of plagioclase, augite, pseudomorphs after olivine and accessories.
The Rainbow Range is a late Miocene shield volcano 30 km in diameter and covering 370 km2. The flanks are gently dipping and composed of hawaiite, mugearite, trachyte and comenditic flows, the lowest of which are apparently continuous with adjacent plateau lavas.
Lying between the Rainbow Range and Itcha Mountains in the central Anahim Belt, the Ilgachuz Range is a moderately dissected shield volcano.
The Itcha Mountains (or Range) are one of the centres of the Anahim Volcanic Belt and consist of a central shield volcano amidst Miocene and Quaternary plateau lavas. The mountains do not appear to have been studied in great detail petrologically.
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.
Boulders of basalt with white, trapezohedral phenocrysts up to 2.5 cm in diamter, which were thought to be leucite, were reported to occur where Horsefly Creek meets Quesnel Lake (Hoffman, 1896), but they were later recognized to be analcime (A.M. Soregaroli, 1973 - quoted in Currie, 1976a. p.
Takomkane Mountain is an isolated volcanic cone with a single lava flow of nephelinite containing abundant xenoliths of spinel lherzolite.