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Sample: 96-ARh-56

Sample ID: 96-ARh-56 [1] [2]
Station ID: 96-ARh-56
AT Num:
Volcano: Akutan
Possible source:
Eruption:
Collector: Richter, D. H.
Date sampled: 1996-00-00
Sample type 1: Lava
Color:
Final unit: llv
Text Description: Qld - Long Valley domes. Massive, structureless bodies, as much as 1 km in diameter, enclosed in mineralogically similar monolithologic breccias. Rock is dark gray to olive black, porphyritic andesite (59.6% SiO2) containing phenocrysts of plagioclase (5-20%, 2-4 mm), clinopyroxene (trace-3%, 2-4 mm), orthopyroxene (trace -3%, 1-4 mm), and olivine (0-trace) in a cryptocrystalline to pilotaxitic groundmass. Whole rock 40Ar/39Ar mean age of andesite (loc E) is 0.58 +/- 0.04 Ma).
Sample Location:

References Cited

[1] Geology of Akutan Island, Alaska, 1998

Richter, D. H., Waythomas, C. F., McGimsey, R. G., and Stelling, P. L., 1998, Geology of Akutan Island, Alaska: U.S. Geological Survey Open-File Report 98-0135, 22 p., 1 sheet, scale 1:48,000.

[2] The eruptive history, magmatic evolution, and influence of glacial ice at long-lived Akutan volcano, eastern Aleutian Islands, Alaska, 2020

Coombs, M.L., and Jicha, B.R., 2020, The eruptive history, magmatic evolution, and influence of glacial ice at long-lived Akutan volcano, eastern Aleutian Islands, Alaska: GSA Bulletin, 29 p., https://doi.org/10.1130/B35667.1.