Sample: 53-F-42
| Sample ID: | 53-F-42 [1] |
| Station ID: | 53-F-42 |
| 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 dacite (?) porphyry from the Unalaska formation at Hive Bay halfway between Staraya Bay and Udagak Strait. It is light gray and contains chalky plagioclase and ferromagnesian phenocrysts 1 to 2 millimeters long. Phenocrysts compose 1 percent of the rock, consisting of subhedral laths of albite with apatite inclusions. The groundmass has an indistinct intersertal texture and consists of abundant subhedral laths of albite, a trace of a granular black opaque mineral, and a trace of quartz that may be primary. Alteration is intense, albite and kaolin are pervasive and abundant, quartz is common and intersertal; calcite is common and forms scattered patches, especially near altered ferromagnesian minerals; and chlorite and uralite (?) are common alteration products of the ferromagnesian minerals. |
| 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