Middle Miocene to Oligocene shallow intrusions (AZTi;0)

Middle Miocene to Oligocene shallow intrusions

Generally very fine-grained, porphyritic rhyolite to dacite in small, irregular-shaped bodies formed as subvolcanic intrusions in volcanic fields of southern and western Arizona, or in concentrated zones of dikes in the Mohave and Black Mountains of northwestern Arizona. The unit consists of mafic tuff, breccia and shallow intrusions at Buell Park in northeastern Arizona. (14-35 Ma)

State	Arizona
Name	Middle Miocene to Oligocene shallow intrusions
Geologic age	Oligocene to Middle Miocene
Lithologic constituents	Major Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-rhyolite (Dike or sill) Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-dacite (Dike or sill) Igneous > Volcanic > Mafic-volcanic (Pyroclastic-tuff, Volcaniclastic-volcanic breccia)The unit consists of mafic tuff, breccia and shallow intrusions at Buell Park in northeastern Arizona.
Comments	Includes Navajo volcanic field minettes
References	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 Spencer, J.E., and Reynolds, S.J., 1989, Middle Tertiary tectonics of Arizona and adjacent areas, in Jenney, J.P., and Reynolds, S.J., editors, Geologic evolution of Arizona: Arizona Geological Society Digest 17, p. 539-574.
NGMDB product	NGMDB product page for 34746
Counties	Apache - Cochise - Graham - La Paz - Maricopa - Mohave - Pima - Yuma

Middle Miocene to Oligocene shallow intrusions

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

Spencer, J.E., and Reynolds, S.J., 1989, Middle Tertiary tectonics of Arizona and adjacent areas, in Jenney, J.P., and Reynolds, S.J., editors, Geologic evolution of Arizona: Arizona Geological Society Digest 17, p. 539-574.