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Mount Pleasant: Lithic Ash Flow Tuff


Colour image of round, tube-like sample of gray rock mottled with white and pink rock
Mount Pleasant: Lithic Ash Flow Tuff. Devonian. Mount Pleasant, New Brunswick. Collector: M. McLeod. New Brunswick Museum (NBMR 1813). Image width 19 cm. The Mount Pleasant mineral deposit began its history near the end of the Devonian Period. Magma exploded at the surface to form a broad volcanic cone, while below the surface the melt cooled to create granitic rocks. The chemistry of the magma caused the granites to be enriched in tungsten, molybdenum, tin and other metals. The volcano produced deposits of layered ash flow and crystal tuff. The Carrow Formation is part of the exocaldera sequence of the Mount Pleasant caldera.