Intrusive and extrusive igneous rocks

Composition ranges from hornblende monzonite to basalt. In Yellowstone area includes andesite and basalt of Emerald Lake (age about 2 Ma), rhyolite of Broad Creek, Pliocene Junction Butte Basalt, and gravel of Mount Everts. Age of basalt on Crescent Mountain 3.6 Ma.
State Wyoming
Name Intrusive and extrusive igneous rocks
Geologic age Miocene-Pliocene
Lithologic constituents
Igneous > Volcanic > Mafic-volcanic > Basalt
Igneous > Volcanic > Mafic-volcanic > Andesite
Igneous > Plutonic > Syenitic > Monzonitehornblende monzonite
Igneous > Volcanic > Felsic-volcanic > Rhyolite
NGMDB product
Counties Lincoln - Park - Teton