Alaska Volcano Observatory

Porphyritic two-pyroxene andesite. Phenocrysts of plagioclase, clinopyroxene, orthopyroxene, and opaque oxides in a groundmass of microlites with subordinate interstitial clear glass. One of several diverse lithologies collected from single location consisting of avalanche debris sitting on top of Umbrella Glacier at ~2200 foot elevation. Location implies these all came from Iliamna, central peak. "i" denotes fist-sized rounded blobs of macroscopically different magma enclosed in homogeneous host.

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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