The Marron Formation is a sequence of early Tertiary lavas associated with which are a number of intrusions, referred to as the Coryell Intrusions, which are thought to be consanguineous. Both lavas and intrusions probably extend beyond the area indicated by the map (Fig.
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Approximately 50 km east of Atlin and 2 km north of the Mount Llangorse quartz diorite intrusion five small intrusions of nephelinite cut thermally altered Permian-Pennsylvanian cherts.
Several peralkaline dykes up to a metre thick have been described from the central part of the Atsutla Range. The dykes are banded and contain abundant, zoned spherulites up to 6 mm in diameter of alkali feldspar, albite, quartz, riebeckite and aegirine. Rock analyses are available.
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.