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Sample: 84ARh-70

Sample ID: 84ARh-70 [1]
Station ID: 84ARh-70
AT Num:
Volcano:
Possible source:
Eruption:
Collector: Richter, D. H.
Date sampled: 1984-00-00
Sample type 1: Lava
Color:
Final unit:
Text Description: Wrangell Lava. Dacite dome field. Dacite porphyry domes (Tertiary) - Broad belt of at least eight coalesced endogenous and exogenous dacite domes that extends more than 19 km around and under the Sonya Creek shield volcano. The dacite (65.8-66.3% SiO2; map nos. 26-28) is coarsely porphyritic containing as much as 30% large (as much as 5 mm) phenocrysts of plagioclase and locally highly altered hornblende. A K-Ar date of 23 Ma (map letter B) was obtained on hornblende from a dome overlain by Sonya Creek intracaldera (?) rocks.
Sample Location:

References Cited

[1] Geologic map of the McCarthy D-1 Quadrangle, Alaska, 2000

Richter, D. H., Ratte, J. C., Leeman, W. P., and Menzies, Martin, 2000, Geologic map of the McCarthy D-1 Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I 2695, unpaged, 1 sheet, scale 1:63,360.