Sample: 54-F-55
| Sample ID: | 54-F-55 [1] |
| Station ID: | 54-F-55 |
| AT Num: | |
| Volcano: | Makushin |
| Possible source: | |
| Eruption: | |
| Collector: | Fraser, G. D. |
| Date sampled: | 1954-01-01 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | |
| Text Description: | Olivine-bearing andesite porphyry from the Makushin volcanics one-half mile south of the vent to Makushin Volcano. It is dark gray and vuggy and contains plagioclase and pyroxene phenocrysts 2-3 millimeters long. Phenocrysts compose 25 percent of the rock: 14 percent sodic labradorite, which forms euhedral to anhedral grains, fragments, and stubby crystals, and which has normal and oscillatory zones, zones of dusty inclusions, and apatite inclusions; 5 percent euhedral crystals and fragments of augite(?); 2 percent subhedral to anhedral hypersthene with augite (?) reaction rims; 3 percent anhedral olivine; and 1 percent subhedral to anhedral magnetite. The groundmass has an intergranular to obscured texture and includes abundant laths and stubby crystals of calcic andesine, much glass and granular augite (?), and traces of hypersthene, olivine, and a granular black opaque mineral. |
| Sample Location: |
References Cited
[1] Geology of Unalaska Island and adjacent insular shelf, Aleutian Islands, Alaska, 1961
Drewes, Harald, Fraser, G. D., Snyder, G. L., and Barnett, H. F. Jr., 1961, Geology of Unalaska Island and adjacent insular shelf, Aleutian Islands, Alaska: in Investigations of Alaskan volcanoes, U.S. Geological Survey Bulletin 1028-S, p. 583-676, 3 sheets, scale 2 at 1:250,000 and 1 unknown.
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plate 77 PDF 250 KB
table 1 PDF 326 KB