Pre-Upper Jurassic metamorphic rocks of the low-grade zone (WApJph;0)

State	Washington
Name	Pre-Upper Jurassic metamorphic rocks of the low-grade zone
Geologic age	Jurassic
Lithologic constituents	Major Metamorphic > Metasedimentary > Metaclastic > Phyllite (Glaucophane-schist)Darrington Phyllite metamorphosed in blueschist facies (Misch, 1977, Brown, 1974). Minor Metamorphic > Schist (Greenschist, Amphibolite epidote-amphibolite)Included in Easton Schist in Central Cascades (Foster, 1960). Incidental Metamorphic > Metasedimentary > Metacarbonate > Marble Metamorphic > Granulite Sedimentary > Clastic > Siltstone (Calcareous, Tuffaceous)Ellemeham Formation in Okanogan County. Sedimentary > Chemical > Chert (Bed)Radiolarian Sedimentary > Clastic > Conglomerate (Bed)Includes metaconglomerate. Igneous > Plutonic > Gabbroic > GabbroMetagabbro Metamorphic > Metaigneous > GreenstoneGreenstone comprises tuffs and flows (Rinehart and Fox, 1972). Sedimentary > Clastic > Sandstone > Graywacke (Bed)Part of Peshastin formation of central Washington (Southwick, 1974). Metamorphic > Metasedimentary > Metaclastic > QuartziteLocally in Okanogan County. Metamorphic > Metasedimentary > Metaclastic > Slate Sedimentary > Carbonate > Limestone (Lens) Metamorphic > Metasedimentary > Metaclastic > ArgillitePart of Peshastin formation of central Washington (Southwick, 1974).
Stratigraphic units	Darrington Phyllite (part of the Easton Metamorphic Suite); Kobau Formation; Ellemeham Formation; Chelan Batholithic Complex (in part: Twisp Valley Schist); Anarchist series (in part); Peshastin formation (part of Ingalls Tectonic Complex)
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. Rinehart, C.D., and Fox, K.F.Jr., 1972, Geology and Mineral Deposits of the Loomis Quadrangle, Okanogan County, Washington: Washington Division of Mines and Geology Bulletin No. 64, 124 p. Misch, P., 1977, Bedrock Geology of the North Cascades, in Brown, E. H. and Ellis, R. C. (eds.), Geological Excursions in the Pacific Northwest, Geological Society of America 1977 Annual Meeting, Seattle: Western Washington University, p. 1-62. 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. Barksdale, J.D., 1975, Geology of the Methow Valley, Okanogan County, Washington: Washington Division of Geology and Earth Resources Bulletin no. 48, 72 p. Brown, E.H., Comparison of the Mineralogy and Phase Relations of Blueschists from the North Cascades, Washington, and Greenschists from Otago, New Zealand: Geological Society of America Bulletin, v. 85, no. 3, p. 333-344. 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. Stout, M.L., 1964, Geology of a Part of the South-Central Cascade Mountains, Washington: Geological Society of America Bulletin, v. 75, no. 4, p 317-334. Adams, J.B., 1964, Origin of the Black Peak Quartz Diorite, Northern Cascades, Washington: American Journal of Science, v. 262, no. 3, p. 290-306. Duggan, K.M. and Brown, E.H., 1994, Correlation of the Tonga Formation and Chiwaukum Schist, North Cascades, Washington: Implications for Late Cretaceous orogenic mechanisms: Tectonics, v. 13, no. 6, p. 1411-1424.
NGMDB product	NGMDB product page for 30777
Counties	Chelan - King - Kittitas - Okanogan - Skagit - Snohomish - Whatcom

State

Name

Pre-Upper Jurassic metamorphic rocks of the low-grade zone

Geologic age

Jurassic

Lithologic constituents

Major

Metamorphic > Metasedimentary > Metaclastic > Phyllite (Glaucophane-schist)Darrington Phyllite metamorphosed in blueschist facies (Misch, 1977, Brown, 1974).

Minor

Metamorphic > Schist (Greenschist, Amphibolite epidote-amphibolite)Included in Easton Schist in Central Cascades (Foster, 1960).

Incidental

Metamorphic > Metasedimentary > Metacarbonate > Marble

Metamorphic > Granulite

Sedimentary > Clastic > Siltstone (Calcareous, Tuffaceous)Ellemeham Formation in Okanogan County.

Sedimentary > Chemical > Chert (Bed)Radiolarian

Sedimentary > Clastic > Conglomerate (Bed)Includes metaconglomerate.

Igneous > Plutonic > Gabbroic > GabbroMetagabbro

Metamorphic > Metaigneous > GreenstoneGreenstone comprises tuffs and flows (Rinehart and Fox, 1972).

Sedimentary > Clastic > Sandstone > Graywacke (Bed)Part of Peshastin formation of central Washington (Southwick, 1974).

Metamorphic > Metasedimentary > Metaclastic > QuartziteLocally in Okanogan County.

Metamorphic > Metasedimentary > Metaclastic > Slate

Sedimentary > Carbonate > Limestone (Lens)

Metamorphic > Metasedimentary > Metaclastic > ArgillitePart of Peshastin formation of central Washington (Southwick, 1974).

Stratigraphic units

Darrington Phyllite (part of the Easton Metamorphic Suite); Kobau Formation; Ellemeham Formation; Chelan Batholithic Complex (in part: Twisp Valley Schist); Anarchist series (in part); Peshastin formation (part of Ingalls Tectonic Complex)

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.

Rinehart, C.D., and Fox, K.F.Jr., 1972, Geology and Mineral Deposits of the Loomis Quadrangle, Okanogan County, Washington: Washington Division of Mines and Geology Bulletin No. 64, 124 p.

Misch, P., 1977, Bedrock Geology of the North Cascades, in Brown, E. H. and Ellis, R. C. (eds.), Geological Excursions in the Pacific Northwest, Geological Society of America 1977 Annual Meeting, Seattle: Western Washington University, p. 1-62.

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.

Barksdale, J.D., 1975, Geology of the Methow Valley, Okanogan County, Washington: Washington Division of Geology and Earth Resources Bulletin no. 48, 72 p.

Brown, E.H., Comparison of the Mineralogy and Phase Relations of Blueschists from the North Cascades, Washington, and Greenschists from Otago, New Zealand: Geological Society of America Bulletin, v. 85, no. 3, p. 333-344.

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.

Stout, M.L., 1964, Geology of a Part of the South-Central Cascade Mountains, Washington: Geological Society of America Bulletin, v. 75, no. 4, p 317-334.

Adams, J.B., 1964, Origin of the Black Peak Quartz Diorite, Northern Cascades, Washington: American Journal of Science, v. 262, no. 3, p. 290-306.

Duggan, K.M. and Brown, E.H., 1994, Correlation of the Tonga Formation and Chiwaukum Schist, North Cascades, Washington: Implications for Late Cretaceous orogenic mechanisms: Tectonics, v. 13, no. 6, p. 1411-1424.

NGMDB product

NGMDB product page for 30777

Counties

Chelan - King - Kittitas - Okanogan - Skagit - Snohomish - Whatcom