Sample: 47AC116
| Sample ID: | 47AC116 [1] [2] |
| Station ID: | 47AC116 |
| AT Num: | |
| Volcano: | Three-quarter cone |
| Possible source: | |
| Eruption: | |
| Collector: | Unknown, Unknown |
| Date sampled: | 1947-01-01 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | Threequarter Cone |
| Text Description: | Andesite vitrophyre from an agglomerate from Three-quarter Cone (121,700' E, 291,900' N). This is a dark-gray rock, aphanitic, with small tabular plagioclase phenocrysts showing a parallel arrangement. About 5 percent of the rock is plagioclase phenocrysts (1 mm in diameter), having an average composition of An58. A few phenocrysts are hypersthene and olivine. The groundmass is mostly plagioclase microlites (0.05 mm long), minute granules of augite(?), and magnetite dust, in brown glass, having an index of 1.546. |
| 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.
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