Sample: 54-F-5
| Sample ID: | 54-F-5 [1] |
| Station ID: | 54-F-5 |
| 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: | Pyrite-bearing dacite vitrophyre from the Unalaska formation 1mile east of Chernofski Harbor. It is black and contains plagioclase phenocrysts 1 to 4 millimeters long. Phenocrysts compose 5 percent of the rock: 2 percent calcic labradorite, which form embayed crystals, euhedral laths and stubby crystals, and fragments, and which have oscillatory zones and apatite inclusions ; 1 percent euhedral augite (?) ; 1 percent euhedral hypersthene; and a trace of euhedral to subhedral ilmenitic magnetite. Microlites of plagioclase are common and of apatite rare. The groundmass is a perlitic glass, which contains a few small chlorite(?) spherulites. |
| 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