Sample: 47AC99


Sample ID: 47AC99 [1] [2]
Station ID: 47AC99
AT Num:
Volcano: Ragged Top
Possible source:
Eruption:
Collector: Unknown, Unknown
Date sampled: 1947-01-01
Sample type 1: Lava
Color:
Final unit: Ragged Top
Text Description: Specimen 47AC99 is olivine basalt from one of the latest flows from Ragged Top (148,800' E., 276,000' N.). The flow is about 20 feet thick, consists of medium-gray (N5) holocrystalline-porphyrytic dosemic basalt, with pilotaxitic texture. The phenocrysts consist of plagioclase (2 mm in diameter), averaging about An82, olivine (0.5 mm in diameter), augite (2 mm in diameter) that is dark green in hand specimen, and magnetite (0.5 mm in diameter). The groundmass consists of magnetite, augite, plagioclase, and interstitial orthoclase (?) .
Sample Location:

References Cited

[1] Geologic reconnaissance of Semisopochnoi Island, western Aleutian Islands, Alaska, 1959

Coats, R. R., 1959, Geologic reconnaissance of Semisopochnoi Island, western Aleutian Islands, Alaska: in Investigations of Alaskan volcanoes, U.S. Geological Survey Bulletin 1028-O, p. 477-519, 1 sheet, scale 1:25,000.
full-text PDF 1.4 MB
plate 59 PDF 2.7 MB

[2] Postglacial eruptive history and geochemistry of Semisopochnoi volcano, western Aleutian Islands, Alaska, 2018

Coombs, M.L., Larsen, J.F., and Neal, C.A., 2018, Postglacial eruptive history and geochemistry of Semisopochnoi volcano, western Aleutian Islands, Alaska: U.S. Geological Survey Scientific Investigations Report 2017-5150, 32 p., https://doi.org/10.3133/sir20175150.