Sample: 53-F-39
| Sample ID: | 53-F-39 [1] |
| Station ID: | 53-F-39 |
| AT Num: | |
| Volcano: | Makushin |
| Possible source: | |
| Eruption: | |
| Collector: | Fraser, G. D. |
| Date sampled: | 1953-01-01 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | |
| Text Description: | Albitized andesite(?) porphyry from the Unalaska formation, 1 1/2 miles south of Hive Bay and about halfway between Staraya Bay and Udagak Strait. It is medium-light gray to medium gray and has chalky plagioclase phenocrysts 1 to 5 millimeters long. Phenocrysts compose 5 percent of the rock: 4 percent albite, which forms euhedral to subhedral laths and stubby crystals having apatite inclusions; and 1 percent euhedral to anhedral magnetite. The groundmass is mottled and indistinct. Alteration is intense: albite and kaolin are pervasive; calcite is common and forms irregular patches near albite clusters; uralite(?) is present; and quartz is rare and forms scattered grains on crudely aligned pods. |
| 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