Sedimentary rocks associated with flood basalts.

Fluvial and lacustrine deposits associated with Columbia River Basalt Group and equivalent basalts (17-8 Ma); consolidated to weakly consolidated sandstone, siltstone, arkose, conglomerate, claystone, and tuffaceous sediment; subordinate intercalated basalt and rhyolitic tuff. Includes Payette and Sucker Creek formations in southwestern Idaho, sediments associated with basalt of Weiser in western Idaho, and Latah Formation in northern Idaho. Includes sedimentary rocks of uncertain origin in southwest corner of Idaho. (Quaternary to Eocene Continental Sediments and Sedimentary Rocks).
State Idaho
Name Sedimentary rocks associated with flood basalts.
Geologic age Miocene
Lithologic constituents
Major
Sedimentary > Clastic > Mixed-clastic (Bed, Tuffaceous)Consolidated to weakly consolidated sandstone, siltstone, arkose, conglomerate, claystone, and tuffaceous sediment.
Minor
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic-tuff)Subordinate intercalated basalt and rhyolitic tuff.
Igneous > Volcanic > Mafic-volcanic > BasaltSubordinate intercalated basalt.
References

Lewis, Reed S., Link, Paul K., Stanford, Loudon R., and Long, Sean P., Geologic Map of Idaho, 2012, Idaho Geological Survey, Geologic Map 9 (M-9); Scale 1:500,000.

NGMDB product
Counties Ada - Adams - Benewah - Boise - Camas - Canyon - Cassia - Clearwater - Elmore - Gem - Idaho - Kootenai - Latah - Owyhee - Payette - Shoshone - Valley - Washington