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Sample: 81ARj 11a

Sample ID: 81ARj 11a [1]
Station ID: 81ARj 11a
AT Num:
Volcano: Ugashik caldera
Possible source:
Eruption:
Collector: Riehle, J. R.
Date sampled: 1981-01-01
Sample type 1: Lahar
Color:
Final unit:
Text Description: Porphyritic plagioclase-orthopyroxene dacite (s; high-silica andesite G). Glassy groundmass contains randomly oriented phenocrysts of orthopyroxene and larger phenocrysts of plagioclase (AN 64-68). Some parts of the thin section have glomeroporphyritic pyroxene and plagioclase; bulk of the phenocrysts are individual crystals. Plagioclase is weakly zoned.
Sample Location:

References Cited

[1] Map and tables showing geochronology and whole-rock geochemistry of selected samples, Ugashik and part of Karluk quadrangles, Alaska, 1992

Wilson, F.H., and Shew, Nora, 1992, Map and tables showing geochronology and whole-rock geochemistry of selected samples, Ugashik and part of Karluk quadrangles, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1539-E, 34 p., 2 sheets, scale 1:250,000.