Pre-Tertiary ultrabasic intrusive rocks

Peridotite and pyroxenite; generally altered partly or completely to serpentine. Includes serpentinite and saxonite on Sumas Mountain, Whatcom County.
State Washington
Name Pre-Tertiary ultrabasic intrusive rocks
Geologic age Late-Jurassic
Lithologic constituents
Major
Metamorphic > Metaigneous > SerpentiniteIncludes serpentinized peridotite and serpentinized pyroxinite.
Minor
Igneous > Plutonic > Ultramafic > PeridotiteMay include dunite (see WApTd for dunite of Fidalgo complex).
Incidental
Metamorphic > Schist
Igneous > Plutonic > Gabbroic > Gabbro
Metamorphic > Granoblastic > Granofels
Igneous > Plutonic > Dioritic > Diorite
Metamorphic > Metaigneous > Greenstone
Metamorphic > Amphibolite
Igneous > Plutonic > Ultramafic > Pyroxenite
Metamorphic > Granoblastic > Hornfels
Metamorphic > Metasedimentary > Metaclastic > Phyllite
Comments The Fidalgo group is located on the San Juan Islands; the Ingalls Tectonic Complex is located in central Washington and makes up the bulk of this unit. The Ingalls Tectonic Complex represents an ophiolite with facies grading from greenschist and zeolitic (prehnite-pumpellyite) to hornfels at its contact with the Mt. Stuart batholith (Tabor and others, 1982, 1987). Dragovich and others, 2002, reports that most of this unit is metamorphosed to talc-, tremolite-, or anthophyllite-bearing rock near plutons to silica-carbonate rock near faults. The referenced literature does not specify facies for each lithology, but I would assume that all of the above grades can be applied to almost all the lithologies though relative quantities of each lithology and facies combination are unknown; hence I do not specify facies in the lithology coding.
Stratigraphic units Fidalgo Complex (in part); Ingalls Tectonic Complex (in part); Chopaka Intrusive Complex (in part)
References

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.

Stoffel, K.L., Joseph, N.L., Waggoner, S.Z., Gulick, C.W., Korosec, M.A., Bunning, B.B., 1991, Geologic Map of Washington--Northeast Quadrant: Washington Division of Geology and Earth Resources Geologic Map, GM-39, scale 1:250,000.

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., Frizzell, V.A.,Jr., Booth, D.B., Waitt, R.B., Whetten, J.T., Zartman, R.E., 1993, Geologic Map of the Skykomish River 30- by 60-Minute Quadrangle, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1963, scale 1:100,000.

Tabor, R.W., Frizzell, V.A.,Jr., Whetten, J.T., Waitt, R.B., Swanson, D.A., Byerly, G.R., Booth, D.B., Hetherington, M.J., Zartman, R.E., 1987, Geologic Map of the Chelan 30-Minute by 60-Minute Quadrangle, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1661, scale 1:100,000.

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.

Hibbard, M.J., 1971, Evolution of a Plutonic Complex, Okanogan Range, Washington: Geological Society of America Bulletin, v. 82, no. 11, p. 3013-3048.

NGMDB product
Counties Chelan - Ferry - Kittitas - Okanogan - Skagit - Whatcom