Precambrian volcanic rocks

Mostly homogenous schistose greenstone; in places massive, mottled, and containing conspicuous calcite and epidote. Tuffaceous chlorite schist in upper part in northern Pend Oreille County. Amphibolite and plagioclase amphibolite in Little Pend Oreille Lakes district. Massive to sheared or schistose greenstone with dark-green ovoid spots; agglomeratic and amygodaloidal in places; sheared pillows near Blue Creek, central Stevens County; minor intrusive phase and probable center of eruption west of Finch magnesite quarry; central to southwestern Stevens County.
State Washington
Name Precambrian volcanic rocks
Geologic age Late-Proterozoic
Lithologic constituents
Metamorphic > Metaigneous > GreenstoneIncludes flows, breccia, tuff, and volcaniclastic rock. Greenstone of Huckleberry Formation has major- and trace-element geochemistry consistant with that of a tholeiitic basalt extruded in a continental rift setting (Waggoner, 1990b).
Metamorphic > Schist (Greenschist)
Metamorphic > Gneiss
Metamorphic > Amphibolite
Sedimentary > Clastic > Conglomerate (Bed)
Comments Leola volcanics include minor conglomerate and diamictite in the lower part of the unit (Joseph, 1990a); conglomerate member of Huckleberry Formation is included in unit WAPCc).
Stratigraphic units Windermere Group: Huckleberry Formation (in part: volcanic member); Leola Volcanics

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.

Park, C.F.Jr., and Cannon, R.S.Jr., 1943, Geology and Ore Deposits of the Metaline Quadrangle, Washington: U. S. Geological Survey Professional Paper 202, 81 p.

Campbell, I. and Loofbourow, J.S.Jr., 1962, Geology of the Magnesite Belt of Stevens County Washington, U. S. Geological Survey Bulletin 1142-F, F1-F53 p.

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.

Joseph, N.L., 1990a, Geologic Map of the Colville 1:100,000 Quadrangle, Washington-Idaho: Washington Division of Geology and Earth Resources Open File Report 90-13, 78 p., 1 pl.

Waggoner, S.Z., 1990b, Geologic Map of the Chewelah 1:100,000 Quadrangle, Washington-Idaho: Washington Division of Geology and Earth Resources Open File Report 90-14, 63 p., 1 pl.

NGMDB product
Counties Pend Oreille - Stevens