Sample: 54-D-33
| Sample ID: | 54-D-33 [1] |
| Station ID: | 54-D-33 |
| AT Num: | |
| Volcano: | Makushin |
| Possible source: | |
| Eruption: | |
| Collector: | Drewes, Harald |
| Date sampled: | 1954-01-01 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | |
| Text Description: | Olivine basalt porphyry from the Makushin volcanics 4 1/4 miles south of Tabletop Mountain and 4 miles east of Sugarloaf Cone. It is medium dark gray to grayish purple and contains plagioclase, pyroxene, and olivine phenocrysts 1-4 millimeters long. Phenocrysts compose 30 percent of the rock : 15 percent labradorite (?) , which forms euhedral laths to anhedral fragments, and stubby crystals, and which contains oscillatory and normal zones, and zones of dusty inclusions; 10 percent augite or diopside, which form faintly zoned euhedral grains and fragments ; 5 percent subhedral to anhedral olivine. The groundmass has a granular to flow texture and consists of abundant plagioclase, much clinopyroxene and a black opaque mineral, and traces of olivine(?) and cristobalite. Alteration is sparse; chlorite (?) replaces olivine. |
| 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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table 1 PDF 326 KB