Sample: 54-F-51
| Sample ID: | 54-F-51 [1] |
| Station ID: | 54-F-51 |
| 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 feldspathic basalt from the Eider Point basalt 1 mile southwest of Pakushin Cone. It is medium dark gray and contains plagioclase phenocrysts shorter than 1 mm. Phenocrysts compose 50 percent of the rock: 35 percent sodic labradorite, which forms subhedral crystals and stubby crystals, and which has normal zones, rare oscillatory zones, and some vermicular zones of intergrown groundmass; 15 percent olivine, which forms euhedral to subhedral crystals and embayed crystals. The groundmass has a granular and glassy texture and consists of much euhedral stubby calcic andesine, much subhedral to anhedral olivine, much euhedral to granular augite(?), and a trace of cristobalite(?). |
| 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 75 PDF 6.7 MB
plate 76 PDF 113 KB
plate 77 PDF 250 KB
table 1 PDF 326 KB