Basic intrusive rocks, undivided

Predominantly gabbro; includes some serpentine. Age undetermined.
State Washington
Name Basic intrusive rocks, undivided
Geologic age Jurassic in central Cascades; Oligocene to Eocene in northern Cascades
Lithologic constituents
Igneous > Plutonic > Dioritic > DioriteIncludes hornblende, quartz, and pyroxene diorite.
Igneous > Plutonic > Gabbroic > GabbroIncludes uralitized gabbro (greenstone of amphibolite facies) and gabbronorite in northern Whatcom County.
Metamorphic > Metaigneous > Serpentinite
Comments Diabase (diorite) outcrop in central Cascades (Foster, 1960, Tabor and others, 1982, Dragovich and others, 2002); diorite, including quartz diorite, in Whatcom and Snokomish Counties (Dragovich and others, 2002). Much of the gabbro in central Washington is uralitized (Southwick, 1974).
Stratigraphic units Ingalls Tectonic Complex (in part)

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.

Foster, R.J., 1960, Tertiary Geology of a Portion of the Central Cascade Mountains, Washington: Geological Society of America Bulletin v. 71, no. 2, p. 99-126.

Tabor, R.W., Waitt, R.B.,Jr., Frizzell, V.A.,Jr., Swanson, D.A., Byerly, G.R., Bentley, R.D., 1982, Geologic Map of the Wanatchee 1:100,000 Quadrangle, Central Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1311, scale 1:100,000.

Southwick, D.L., 1974, Geology of the Alpine-type Ultramafic Complex and Mount Stuart, Washington: Geological Society of America Bulletin, v. 85, no. 3, p 391-402.

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.

NGMDB product
Counties Chelan - Kittitas - Skagit - Snohomish - Whatcom