Sample: 87-AWs-5

Sample ID:	87-AWs-5 ^[1]
Station ID:	87-AWs-5
AT Num:
Volcano:	Wrangell
Possible source:
Eruption:
Collector:	Unknown, Unknown
Date sampled:	1987-00-00
Sample type 1:	Lava
Color:
Final unit:
Text Description:	Chetaslina eruptive center dacite flow (Pleistocene). Pale-red to medium-gray, massive porphyritic dacite that contains phenocrysts of plagioclase (5-10%, 1-2 mm), aligned oxyhornblende (5-10%, as long as 6 mm), and opaque minerals (trace to 1%, 1 mm) in microtrachytic groundmass of plagioclase microlites and cryptocrystalline material. * * * Hornblende from sample (loc. 36) yielded K-Ar age of 0.84+/-0.14 Ma. Thickness about 300 m, but top not exposed.
Sample Location:

References Cited

[1] Geologic map of the Gulkana A-1 Quadrangle, south-central Alaska, 1994

Richter, D. H., Duffield, W. A., Sawyer, D. A., Schmoll, H. R., and Ratte, J. C., 1994, Geologic map of the Gulkana A-1 Quadrangle, south-central Alaska: U.S. Geological Survey Geological Quadrangle Map GQ 1728, unpaged, 1 sheet, scale 1:63,360.