Sample: 84-ARh-91

Sample ID:	84-ARh-91 ^[1]
Station ID:	84-ARh-91
AT Num:
Volcano:
Possible source:
Eruption:
Collector:	Richter, D. H.
Date sampled:	1984-00-00
Sample type 1:	Lava
Color:
Final unit:
Text Description:	Unassigned rocks, older rhyolite dome (Pleistocene). Pinkish-gray, sparsely porphyritic rhyolite that contains 1-2% phenocrysts of plagioclase, opaque minerals, and possibly some altered mafic minerals, in microfelty groundmass of feldspar. Only exposed in one locality near northwest corner of quadrangle. * * * Whole-rock K-Ar age is 1.23+/-0.07 Ma.
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.

Alaska Volcano Observatory

Sample: 84-ARh-91

References Cited

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