Sample: 91CND12
Sample ID: | 91CND12 [1] |
Station ID: | 91CND12 |
AT Num: | |
Volcano: | Douglas |
Possible source: | |
Eruption: | |
Collector: | Nye, C. J. |
Date sampled: | 1991-01-01 |
Sample type 1: | Lava |
Color: | |
Final unit: | |
Text Description: | Sample of block of dense glassy pyroclast. Similar blocks, radially fractured and up to ~80 cm, litter the surface of this ridge, rather than coming from a unit in section, and are thus presumably very young. Porphyritic two-pyroxene dacite with ~40% phenocrysts and glomerocrysts (individual pyroxene and plagioclase crystals typically 1.0 x 0.3 mm) in a groundmass of clear glass with only minor microlites. Conchoidal fractures in the glass suggest collapse of former vesicles. This is the only Douglas sample collected in 1991 with abundant glass. |
Sample Location: |