The Mount Meager volcanic complex is the northernmost major volcanic center in the Canadian extension of the Cascade Range. This Tertiary to Holocene complex has erupted rocks of mafic to felsic composition from at least 8 vents. The most recent eruption produced a pyroclastic flow and lava flow from a NE flank vent about 2350 years ago. This view from the Lillooet River valley to the west shows, from left to right, the glacially dissected volcanic necks of Mount Capricorn, Meager Mountain, and Plinth Mountain.

Photo by Willie Scott, 1990 (U.S. Geological Survey).

Additional Photos

Mount Capricorn, Meager Mountain, and Plinth Mountain, from left to right, seen above the Lillooet River valley to the SE, are three of the 8 volcanic centers forming the Tertiary to Holocene Meager volcanic complex. Deep glacial erosion has exposed the interior of a group of dissected rhyodacite volcanic necks forming the highest peaks.

Photo by Lee Siebert, 1987 (Smithsonian Institution).

The inconspicuous ice-and-debris covered vent of the Bridge River eruption, the last eruption of the Meager volcanic complex, is located near the center of the photo immediately above the "inverted-V-shaped" forested valley fill. The Bridge River eruption, the largest-known Holocene explosive eruption in Canada, produced ashfall to the east across British Columbia into Alberta.

Photo by Willie Scott, 1990 (U.S. Geological Survey).

The tree trunk next to the geologist was buried by ash-fall deposits from the Bridge River eruption of the Meager volcanic complex about 2350 years ago, and then overrun by a pyroclastic flow. Its deposit has an unwelded base and a darker, more massive welded layer seen at the top of this photo.

Photo by Willie Scott, 1990 (U.S. Geological Survey).

The pyroclastic-flow deposit forming the foreground canyon wall on the Lillooet River was erupted from the Bridge River vent on the NE flank of the Meager volcanic complex. The inconspicuous vent at the upper right below the skyline notch was the source of an explosive eruption about 2350 years ago that spread ash to the east across British Columbia and Alberta and produced the pyroclastic flow seen here and a 3-km-long rhyodacite lava flow.

Photo by Willie Scott, 1990 (U.S. Geological Survey).