Alaska Volcano Observatory

Very dark gray lava in older volcanics. Geodes and ruby red plagioclase indicate alteration and silica mobilization. Not much fresh rock in immediate area. Porphyritic two-pyroxene dacite. ~25% phenocrysts of plagioclase (up to 1.0 x 0.4 mm), pyroxene (0.8 x 0.3 mm), and opaque Fe-Ti oxides in a matrix of devitrified glass and subordinate microphenocrysts and microlites. Pl:px ~ 3:2

Sample Location:

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Legend

	Red (Warning)
	Orange (Watch)
	Yellow (Advisory)
	Green (Normal)
	Uninstrumented

300 km

200 mi

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References Cited

[1] Geochemistry of some Quaternary lavas from the Aleutian Arc and Mt. Wrangell, 2018

Nye, C.J., Beget, J.E., Layer, P.W., Mangan, M.T., McConnell, V.S., McGimsey, R.G., Miller, T.P., Moore, R.B., and Stelling, P.L., 2018, Geochemistry of some quaternary lavas from the Aleutian Arc and Mt. Wrangell: Alaska Division of Geological & Geophysical Surveys Raw Data File 2018-1, 29 p. http://doi.org/10.14509/29843

publication on DGGS website.

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