Volcanic rocks

Lava flows, flow breccia, and agglomerate dominantly of plagioclase, pyroxene, and hornblende porphyritic and aphyric andesite. Includes flow rocks that range in composition from basalt to rhyolite as well as some interlayered tuff and tuffaceous sedimentary rocks. Commonly metamorphosed to greenschist facies; locally foliated, schistose or gneissic. Includes the Rogue Formation and volcanic rocks commonly assigned to the Galice Formation (Wells and Walker, 1953; Wells and Peck, 1961). Considered to be accreted island-arc terrane
State Oregon
Name Volcanic rocks
Geologic age Late Jurassic
Lithologic constituents
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic)
Igneous > Volcanic > Felsic-volcanic (Pyroclastic, Flow)
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Sedimentary > Clastic > Mudstone (Bed)
Sedimentary > Chemical > Chert (Bed)
NGMDB product
Counties Coos - Curry - Douglas - Jackson - Josephine