Sample: 54-F-53
| Sample ID: | 54-F-53 [1] |
| Station ID: | 54-F-53 |
| 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 porphyry from Makushin volcanics, 1 mile northeast of Pakushin Cone. It is pale purple to grayish purple and contains plagioclase, pyroxene, and olivine phenocrysts 1-4 millimeters long. Phenocrysts compose 25 percent of the rock: 15 percent sodic labradorite, which forms euhedral stubby crystals and fragments, and which contains faint oscillatory and normal zones, zones of dusty inclusions. And apatite inclusions; 6 percent euhedral to subhedral augite (?); 2 percent hypersthene with thin augite(?) reaction rims; 2 percent euhedral to anhedral olivine; and 1 percent subhedral magnetite(?), with some myrmekitic intergrowth in augite(?). The groundmass has a felty to intergranular texture and consists of sodic labradorite, abundant subhedral laths and stubby crystals of much granular augite (?), a black opaque mineral, and a trace of granular 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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plate 75 PDF 6.7 MB
plate 76 PDF 113 KB
plate 77 PDF 250 KB
table 1 PDF 326 KB