Middle Proterozoic diabase

Dark gray to black sills (intrusions mostly parallel to bedding) in strata of the Apache Group and irregular to sheet-like intrusions in other rocks. Present in east-central and southeastern Arizona. Some sills are more than 100 m thick. Exposures are extensive north of Globe. (1050-1150 Ma)
State Arizona
Name Middle Proterozoic diabase
Geologic age Middle Proterozoic
Lithologic constituents
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Dike or sill, Diabase)diabase
Igneous > Plutonic > Gabbroic > Gabbro (Dike or sill, Diabase)diabase
Comments ~ 1.1 Ga. Associated with Grand Canyon Supergroup, and Apache Group (unit Ys)

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.

Elston, D.P., 1989, Grand Canyon Supergroup, northern Arizona: statigraphic summary and preliminary paleomagnetic correlations with parts of other North American Proterozoic successions, in Jenney, J.P., and Reynolds, S.J., editors, Geologi

Wrucke, C.T., 1989, The Middle Proterozoic Apache Group, Troy Quartzite, and associated diabase of Arizona, in Jenney, J.P., and Reynolds, S.J., editors, Geologic evolution of Arizona: Arizona Geological Society Digest 17, p. 239-258.

NGMDB product
Counties Gila - Graham - Maricopa - Navajo - Pinal