Chilcotin Group

Chilcotin Plateau basalts cover a large area in British Columbia. Basaltic lava formed a volcanic plateau running parallel with the Garibaldi Volcanic Belt, about 150 km from the ocean. 

During the Miocene and Pliocene, a volcanic field occurred in British Columbia's Interior Plateau. The basalt is assumed to cover up to 50,000 km2 of the Pacific Northwest. It forms a medium-sized large igneous province, of volume 3300 km3.Regional stratigraphy and age of Chilcotin Group basalts, south-central British Columbia Retrieved on 20012-09-22  

Volcanism still continues from time to time. Eruptions were most vigorous 610 million years ago (mya) and 23 mya, when most of the basalt was released. Smaller eruptions continued from 1.6 mya to 0.01 mya.National Resources Canada - Catalogue of Canadian volcanoes: Chilcotin Plateau basalts  Retrieved on 2008-03-15

 References 

Category:Volcanoes of British Columbia
Category:Igneous rocks