Mount Edziza Volcanic Complex

The distribution of volcanoes on the planets is not uniform. Volcanoes are known on the Earth, Mars, Venus, and several moons of the planets. On Earth, volcanoes are associated with converging and diverging plate margins. Even on these margins however, there are large volcanic complexes that represent the locus of repeated volcanic activity. Iceland, for example, is a large volcanic file on the Midatlantic Ridge. Volcanic complexes occur in plate interiors, for example Hawaii in the middle of the Pacific plate and the Craters of the Moon - Snake River Plain basalt field in the middle of the North American plate.

A smaller volcanic complex, the Mount Edziza Volcanic Complex (Souther, 1992) in northern British Columbia is one of several large volcanic complexes in western Canada. A myriad of volcanic features make up the complex. Basaltic shields, composite volcanoes, rhyolite domes, caldera complexes, and pyroclastic rock bodies are all found in the Mount Edziza Complex. The ages of the volcanic rocks span at least the last 7.5 Ma. The youngest date obtained, 1340 years BP, was obtained from twigs in the soil beneath one of the youngest cinder cones.

This photograph was taken from a young cinder cone on the northwest slope of the Complex. The cinder cone, Eve Cone, that you see in the photograph is one of the youngest features in the Mount Edziza Complex.

What controls the distribution of volcanoes on the planet?
Is the number of factors that control the distribution so large that the distribution appears to be random?
If the past distribution volcanoes was known, could we predict the future distribution?
How long will volcanic activity last on earth? Both Mars and the Moon are likely dead bodies with respect to volcanic activity.

jim.nicholls@shaw.ca