Sample: 74ALe-12


Sample ID: 74ALe-12 [1]
Station ID: 74ALe-12
AT Num:
Volcano: Drum
Possible source:
Eruption:
Collector: Unknown, Unknown
Date sampled: 1974-00-00
Sample type 1: Lava
Color:
Final unit:
Text Description: Dacite flows of Snider Peak - Massive dark gray weathering hornblende-rich flows that radiate from general area of Snider Peak dome. Flows are as much as a 100 m thick but appear to consist of complex multiple-flow cooling units suggesting possibility of more than one source, perhaps in part including second-cycle cone-building flows. They locally contain abundant concentrations of xenoliths and exhibit conspicuous columnar jointing. Rocks are light gray to pinkish medium gray with abundant medium (2-5 mm) phenocrysts of plagioclase and brown hornblende, minor to common hypersthene, and rare biotite, resorbed augite, and olivine generally in a feldspar-rich pilotaxitic to trachytic groundmass. Glassy phases have hyalopilitic and locally spherulitic groundmass textures. Chemistry: samples 23 (74-AMm-76B), 26 (74-ARh-310)
Sample Location:

References Cited

[1] Geologic map of the Gulkana A-2 quadrangle, Alaska, 1979

Richter, D. H., Smith, R. L., Yehle, L. A., and Miller, T. P., 1979, Geologic map of the Gulkana A-2 quadrangle, Alaska: U.S. Geological Survey Geological Quadrangle Map GQ 1520, unpaged, 1 plate, scale 1:63,360.