Sample: 10AZnye03i


Sample ID: 10AZnye03i [1]
Station ID: 10AZ-i3
AT Num:
Volcano:
Possible source:
Eruption:
Collector: Nye, C. J.
Date sampled: 2010-01-01
Sample type 1: Lava
Color:
Final unit:
Text Description: This outcrop is a large lava mass consisting of host lava with abundant rounded magmatic inclusions several cm to 10s of cm across. Host is porphyritic pl-hb andesite w/ 15% pl (5-10mm) and 5% hb (1-3mm) in a fine-grained light greenish-grey gms. Inclusions are very fine-grained and equigranular with pl, px, hb in randomly oriented xl <<1mm (save a few percent mm-sized hb crystals). Northernmost of three domes shown by Coats (1956, USGS Bull 1028-C), who calls these, and two others near downtown Adak, Ta, Andesite porphyry domes. Coats notes these domes are glaciated (thus pre-late Pleistocene), but don't share the structural style of surrounding Finger Bay volcanics (thus not buried, much younger). Coats assigns an early Tertiary age (but he assigns late T to Moffett and Adagdak volcanoes; mid T to Andrew Bay volcano; and Paleozoic to Finger Bay volcs -- clearly too old. My guess would be early to mid Pleistocene for these domes.).
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