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Mount Pleasant: pumice tuff, youngest caldera unit


Colour image of light brown rock
Mount Pleasant: pumice tuff, youngest caldera unit. Devonian-Lower Carboniferous. Mount Pleasant, New Brunswick. Collector: S. McCutcheon, c. 1980. New Brunswick Museum (NBMR 1808) Image width 15 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.