Sample: 73-ARh-111


Sample ID: 73-ARh-111 [1]
Station ID: 73-ARh-111
AT Num:
Volcano:
Possible source:
Eruption:
Collector: Richter, D. H.
Date sampled: 1973-00-00
Sample type 1: Lava
Color:
Final unit:
Text Description: Rhyolite flows and domes. Extensive thick flows and probably domes of gray to pinkish gray devitrified rhyolite with black porphyritic glassy base. Devitrified rocks contain sparse phenocrysts of biotite and plagioclase in an extremely fine-grained felty matrix. Glassy base contains abundant plagioclase and sparse hypersthene in a perlitic glassy matrix. K-Ar date (M.A. Lanphere, written commun., 1974 unpub. data) on plagioclase indicates age of 2.85 +/- 0.05 m.y. (Sample 73-ARh-111).
Sample Location:

References Cited

[1] Geologic map of the Nabesna A-5 quadrangle, Alaska, 1976

Richter, D.H., and Smith, R.L., 1976, Geologic map of the Nabesna A-5 quadrangle, Alaska: US Geological Survey Geologic Quadrangle Map 1292, 1 sheet, available at http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=13027 .