Geology and Minerals
The 2004–2008 volcanic activity of Mount St. Helens in Washington, United States was a documented continuous eruption, which occurred in the form of gradual extrusion of magma. Starting in October 2004 and ceasing in January 2008, a new lava dome was built up. The new dome did not rise above the rim of the crater created by the 1980 eruption of Mount St. Helens.
Gypsum.
Calc-alkaline magma series.
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