Pliocene to late Miocene basaltic rocks

Mostly dark, inconspicuously flat, low-lying or mesa-forming basalt deposited as lava flows. Rocks included in this unit are located almost entirely in the large volcanic fields south and west of Flagstaff, in smaller fields in northwesternmost Arizona, and in the Hopi Buttes volcanic field on the Navajo and Hopi Indian Reservations north of Holbrook. Original volcanic landforms have been obscured by erosion. (4-8 Ma)
State Arizona
Name Pliocene to late Miocene basaltic rocks
Geologic age Late Miocene to Pliocene
Lithologic constituents
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Comments Chiefly Hopi Buttes, "Rim basalts", volcanic fields in northwesternmost Arizona

Richard, S.M., Reynolds, S.J., Spencer, J.E., and Pearthree, P.A., 2000, Geologic Map of Arizona: Arizona Geological Survey Map 35, 1 sheet, scale 1:1,000,000.

Nealey, L.D., and Sheridan, M.F., 1989, Post-Laramide volcanic rocks of Arizona and northern Sonora, Mexico, and their inclusions, in Jenney, J.P., and Reynolds, S.J., editors, Geologic evolution of Arizona: Arizona Geological Society Diges

NGMDB product
Counties Apache - Cochise - Coconino - Mohave - Navajo - Yavapai