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:

References Cited

[1] Geochemistry of some Quaternary lavas from the Aleutian Arc and Mt. Wrangell, 2018

Nye, C.J., Beget, J.E., Layer, P.W., Mangan, M.T., McConnell, V.S., McGimsey, R.G., Miller, T.P., Moore, R.B., and Stelling, P.L., 2018, Geochemistry of some quaternary lavas from the Aleutian Arc and Mt. Wrangell: Alaska Division of Geological & Geophysical Surveys Raw Data File 2018-1, 29 p. http://doi.org/10.14509/29843