Sample: 96-Mc-32B
| Sample ID: | 96-Mc-32B [1] [2] |
| Station ID: | 96-Mc-32 |
| AT Num: | |
| Volcano: | Akutan |
| Possible source: | |
| Eruption: | |
| Collector: | McGimsey, R. G. |
| Date sampled: | 1996-00-00 |
| Sample type 1: | Lava |
| Color: | gray |
| Final unit: | lea |
| Text Description: | Qol- pre-glacial lavas (Pleistocene). Lava flows are exposed locally, mostly around base of present Akutan cone; elsewhere covered by Holocene tephra (Qtu). Flows are typically thick (>5 m) and tend to form prominent cliffs. Rocks are medium gray, dark gray, and olive gray porphyritic andesites (56.5-59.8% SiO2, loc. 10 and 11, table 11) containing phenocrysts of plagioclase (5-30%, 4-5 mm), clinopyroxene (1-7%, 3 mm), orthopyroxene (trace-4%, 1-5 mm), and olivine (0-1%, 2 mm) in cryptocrystalline to pilotaxitic groundmasses. Whole rock 40Ar/39Ar mean age of andesite is 0.36 +/-0.05 Ma. |
| Sample Location: |
