Sample: 54-Sn-55
| Sample ID: | 54-Sn-55 [1] |
| Station ID: | 54-Sn-55 |
| AT Num: | |
| Volcano: | Makushin |
| Possible source: | |
| Eruption: | |
| Collector: | Snyder, G. L. |
| Date sampled: | 1954-01-01 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | |
| Text Description: | Dacite virophyre from the Unalaska formation at Buttress Point, 10 miles southwest of Kuliliak Bay. It is black and has plagioclase phenocrysts as large as 2.5 millimeters, and amygdules with a diameter of 1 to 4 millimeters. Phenocrysts compose 5 percent of the rock: 4 percent sodic andesine, which forms embayed crystals and euhedral to subhedral laths and stubby crystals, and which has normal zones and apatite inclusions; a trace of subhedral hypersthene; a trace of subhedral augite(?) ; and a trace of subhedral to euhedral ilmenitic magnetite. Microlites of plagioclase are common, and of apatite rare. The groundmass is glass, which is slightly devitrified and altered to chlorite (?) and contains 1 percent zeolite (?) -filled amygdules. |
| 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