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Sample: Snyder_1959_2

Sample ID: Snyder_1959_2 [1]
Station ID: unnamed1
AT Num:
Volcano: Little Sitkin
Possible source:
Eruption:
Collector: Snyder, G. L.
Date sampled:
Sample type 1: Lava
Color: dark gray
Final unit:
Text Description: Andesite from typical inclusion in lavas of Double Point dacite. Color: dark gray (N 3). Texture: miarolitic intersertal. Pore space, miarolitic cavities: 20-30 percent. Plagioclase lathes, 45-55 percent, average An60 but range from An26 to An74; megaphenocrysts, 3 percent, show fritted texture. Oxyhornblende, 14 percent, is pleochroic in deep brown and olive brown, occurs in needles with a length-width ratio of 15:1; many hornblende crystals have hollow centers. Orthopyroxene, 6 percent, occurs in euhedral needles with a length-width ratio as much as 30:1. Clinopyroxene, 4 percent, is present as stubby subhedral crystals. Magnetite, 4 percent, anhedrons have a length-width ratio as much as 10:1. Clear brown glass, 14 percent, in groundmass bas N=1.498.
Sample Location:

References Cited

[1] Geology of Little Sitkin Island, Alaska, 1959

Snyder, G. L., 1959, Geology of Little Sitkin Island, Alaska: in Investigations of Alaskan volcanoes, U.S. Geological Survey Bulletin 1028-H, p. 169-210, 1 plate, scale 1:20,000.