Adel Mountain Volcanics

Gray, light brownish gray, and dark gray trachyandesite and trachybasalt flows; dark red, purplish red, and dark grayish green volcanic breccia containing angular clasts of trachybasalt and trachyandesite in matrix of coarse tuff; and dark gray, dark grayish red, brownish gray, and dark grayish green porphyritic shonkinite intrusive rock with augite phenocrysts.
State Montana
Name Adel Mountain Volcanics
Geologic age Cretaceous
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff)trachyandesite
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff)trachybasalt
Minor
Igneous > Plutonic > Syeniticdark grayish green porphyritic shonkinite intrusive rock with augite phenocrysts
References

Vuke, S.M., Porter, K.W., Lonn, J.D., and Lopez, D.A., 2007, Geologic Map of Montana - Compact Disc: Montana Bureau of Mines and Geology: Geologic Map 62-C, 73 p., 2 sheets, scale 1:500,000. This map was digitized in 2012 as a result of a contract between the U.S. Geological Survey and the Montana Bureau of Mines and Geology.

NGMDB product
Counties Cascade - Lewis and Clark