Preliminary Map No. 37: Geology of the Terrace Mountain Tertiary
View Map (PDF 5.7 MB), (1:50 000)
Preliminary Map 37 presents the geology of the Terrace Mountain Tertiary outlier in southern British Columbia. The 1:50 000 scale geology map includes a legend and a cross section.
Pre-Tertiary rocks in the area are bedded rocks including metavolcanics, limestone, schists, chert and quartzite, and mainly granitic intrusions. Six Eocene units are mapped. The lowest consists of sandstones, shales, and coarse conglomerate. Above are units of mainly andesite and dacite lava and breccia, feldspar phyric andesite lava and hornblende trachyte (?), syenite and monzonite feeders to Marron lavas, rhyolite tuff breccia and glassy lava, and dacite and andesite lava and breccia. Possibly Miocene feeder dikes and remnants of olivine basalt lava flows occur on hillsides and ridge tops.
The structure of the area is dominated by block faults that tilted the Tertiary strata. Northerly trending faults predominate; other faults trend northeast and northwesterly.
The Tertiary rocks have potential for epithermal precious metal deposits.
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