Sample: 54-B-11
| Sample ID: | 54-B-11 [1] |
| Station ID: | 54-B-11 |
| AT Num: | |
| Volcano: | Makushin |
| Possible source: | |
| Eruption: | |
| Collector: | Barnett, H. F. J. |
| Date sampled: | 1954-01-01 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | |
| Text Description: | Andesite porphyry from a dike in the Unalaska formation along the south shore of Kalekta Bay. It is light bluish gray to medium gray and has phenocrysts 1 to 3 millimeters long. Phenocrysts compose 20 percent of the rock: 19 percent sodic labradorite to sodic andesine, which forms embayed crystals and subhedral laths and which is zoned normally; a trace of clinopyroxene, which alters to uralite(?) and chlorite; and a trace of pyrite, which forms subhedra associated with clinopyroxene. The groundmass, which has a felty and intersertal texture, consists of abundant subhedral laths of sodic andesine, and also a trace of subhedral clinopyroxene and a granular black opaque mineral. Alteration is moderate: chlorite and uralite(?) are common, and calcite forms disseminated crystals and veinlets. |
| 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