Morrison Formation

Commonly cliff-forming, cross-bedded sandstone lenses alternating with slope-forming siltstone, mudstone and shale. Colors are highly variable, and include greenish gray, reddish brown, pink, white, and purple. Sands were deposited by braided streams with finer sediment representing overbank or lacustrine deposits. (145-160 Ma)
State Arizona
Name Morrison Formation
Geologic age Late Jurassic
Lithologic constituents
Major
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Clastic > Sandstone (Lens)
Sedimentary > Clastic > Mudstone (Bed)
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)
Stratigraphic units Morrison Formation
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.

Blakey, R.C., 1989, Triassic and Jurassic geology of the southern Colorado Plateau, in Jenney, J.P., and Reynolds, S.J., editors, Geologic evolution of Arizona: Arizona Geological Society Digest 17, p. 369-396.

NGMDB product
Counties Apache - Coconino - Navajo