Sample: 53-B-38
| Sample ID: | 53-B-38 [1] |
| Station ID: | 53-B-38 |
| AT Num: | |
| Volcano: | Makushin |
| Possible source: | |
| Eruption: | |
| Collector: | Barnett, H. F. J. |
| Date sampled: | 1953-01-01 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | |
| Text Description: | Slightly altered feldspathic basalt porphyry. It is greenish gray to grayish green and contains phenocrysts 1 to 2 millimeters long. Phenocrysts compose 15 percent of the rock: 12 percent sodic labradorite, which forms embayed crystals, euhedral laths, and irregular grains and which contains normal and oscillatory zones and zones of dusty inclusions; 3 percent augite or diopside, which form euhedral to anhedral crystals and crystal clusters and which alter to chlorite and uralite(?) pseudomorphs ; and a trace of olivine (?) , which appears as chlorite and uralite(?) pseudornorphs. The groundmass has a felty to granular texture and consists of plagioclase, altered pyroxene(?), and a black opaque mineral. Alteration is moderate; chlorite and uralite (?) replace pyroxene and 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.
full-text PDF 3.3 MB
plate 75 PDF 6.7 MB
plate 76 PDF 113 KB
plate 77 PDF 250 KB
table 1 PDF 326 KB