Middle Jurassic volcanic rocks

Andesite, dacite, and minor basalt with slate and graywacke interbeds in the Nooksack River region of Whatcom County.
State Washington
Name Middle Jurassic volcanic rocks
Geologic age Middle Jurassic
Lithologic constituents
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic-volcanic breccia)
Igneous > Volcanic > Felsic-volcanic > Dacite (Flow, Volcaniclastic-volcanic breccia)
Metamorphic > Metasedimentary > Metaclastic > Slate
Sedimentary > Clastic > Sandstone > Graywacke (Bed)
Metamorphic > Metasedimentary > Metaclastic > Argillite
Comments Dragovich and others, 2002 reports that the dacite and andesite is recrystallized and contains metamorphic pumpellyite, chlorite, epidote, albite, and rare aragonite. Misch, 1966, reports that the andesite grades into keratophyre as well as dacite. Neither Dragovich and others, 2002, or Misch, 1966, mention basalt.
Stratigraphic units Wells Creek Volcanics (Nooksack Formation)

Huntting, M.T., Bennett, W.A.G., Livingston, V.E.Jr., and Moen, W.S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.

Dragovich, J.D., Logan, R.L., Schasse, H.W., Walsh, T.J., Lingley, W.S., Jr., Norman, D.K., Gerstel, W.J., Lapen, T.J., Schuster, J.E., Meyers, K.D., 2002, Geologic Map of Washington-Northwest Quadrant: Washington Division of Geology and Earth Resources Geologic Map GM-50, scale 1:250,000.

Misch, P., 1966, Tectonic evolution of the northern Cascades of Washington--A west-cordilleran case history. In Canadian Institute of Mining and Metallurgy; and others, A symposium on the tectonic history and mineral deposits of the western Cordillera in British Columbia and neighboring parts of the United States, Vancouver, 1964: Canadian Institute of Mining and Metallurgy Special Volume 8, p. 101-148, 1 pl.

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