Mafic and intermediate intrusive rocks

Dikes, plugs, and sills of basalt, diabase, gabbro, and lesser andesite that fed many of the Miocene basalt and andesite flows in unit Tc. Some intrusions are rootless and are invasive into sedimentary sequences; includes related breccia and peperite. Includes Depoe Bay and Cape Foulweather dikes, sills, and plugs in the Coast Range (Snavely and others, 1976a, b; Wells and others, 1983)
State Oregon
Name Mafic and intermediate intrusive rocks
Geologic age Miocene
Lithologic constituents
Major
Igneous > Plutonic > Gabbroic > Gabbro (Stock or pipe, Dike or sill)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Stock or pipe, Dike or sill, Diabase)
Minor
Igneous > Plutonic > Dioritic > Diorite (Stock or pipe, Dike or sill)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-andesite (Stock or pipe, Dike or sill)
Comments Northwestern Oregon
References
NGMDB product
Counties Clatsop - Lincoln - Tillamook - Yamhill