Sample: 87-WAD-9
| Sample ID: | 87-WAD-9 [1] |
| Station ID: | 87-WAD-9 |
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| Volcano: | |
| Possible source: | |
| Eruption: | |
| Collector: | Duffield, W. A. |
| Date sampled: | 1987-00-00 |
| Sample type 1: | Lava |
| Color: | |
| Final unit: | |
| Text Description: | Nathlie Mountain hornblende dacite flow (Pleistocene). Medium- to dark-gray, columnar-jointed, massive dacite flow that is moderately to highly porphyritic. Flow contains phenocrysts of rounded plagioclase (5-15%, as large as 5 mm), altered hornblende (1-3%, as long as 2 mm), and hypersthene (trace to 1%, <1 mm), in trachytic to pilotaxitic groundmass of plagioclase microlites and cryptocrystalline material. Mineralogically and chemically similar to hornblende dacite intrusion (Qnd), which suggests that intrusion may have breached surface toward end of Nathlie Mountain volcanic activity. * * * Thickness variable, locally greater than 300 m. |
| Sample Location: |