Mount Meager - Geography and Geology - Regional Geomorphology - Garibaldi Volcanic Belt

Garibaldi Volcanic Belt

Mount Meager is part of the Garibaldi Volcanic Belt, the northernmost segment of the Cascade Volcanic Arc. This volcanic belt includes cinder cones, calderas, stratovolcanoes and subglacial volcanoes that have been active in the Holocene period (10,000 years ago to present). The latest explosive eruption in the Garibaldi Volcanic Belt occurred at a crater on the northeastern flank of Mount Meager, which forms a clearly defined depression.

The GVB extends north from the Watts Point volcano to at least as far as Mount Meager. Little is known about the volcanoes north of Meager, such as Silverthrone and the Franklin Glacier volcanic complex, leaving room for experts to disagree about their nature. For example, some scientists regard the Silverthrone Caldera as the northernmost volcano of the Garibaldi Volcanic Belt, while others contend that the geology of Mount Meager more closely matches that of the GVB. It is also unclear whether the Milbanke Sound Cones are part of the Garibaldi Belt or they are volcanoes formed by different tectonic processes than those in the Garibaldi Belt. However, there is evidence the Silverthrone and Franklin Glacier complexes are related to Cascadia subduction. Geologically, these two volcanoes contain the same rock types as those found elsewhere in the Cascade Arc, including rhyolites, dacites, andesites and basaltic andesites. Such rock types are produced by subduction zone volcanism, indicating volcanism at Silverthrone and Franklin Glacier is probably related to subduction. If these two volcanoes are true Cascade Arc volcanoes, Mount Meager is not the northernmost volcano of the Garibaldi Belt or the Cascade Arc.