Sample: 54-F-32
| Sample ID: | 54-F-32 [1] |
| Station ID: | 54-F-32 |
| 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: | Andesite porphyry from the Unalaska formation along the shore halfway between Humpback Bay and the mouth of Glacier River in Makushin Bay. It is medium gray to medium bluish gray and contains phenocrysts 2 to 4 millimeters long. Phenocrysts compose 10 percent of the rock ; 8 percent sodic andesine, which forms embayed crystals and subhedral to anhedral laths and which contains normal and oscillatory zones and zones of dusty inclusions;2 percent augite(?), which forms euhedral to subhedral crystals, crystal clusters, and pseudomorphs of penninite(?) ; a trace of ilmenitic magnetite, which forms subhedral to anhedral crystals and embayed crystals. The groundmass has a felty to flow texture and consists of abundant subhedral laths of sodic andesine, much pyroxene, and traces of a granular black opaque mineral. Alteration is slight; there are traces of disseminated penninite(?) and uralite(?) and veinlets of epidote and quartz. |
| 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