Middle Proterozoic sedimentary rocks

Red-brown shale and sandstone, buff to orange quartzite, limestone, basalt, black shale, and sparse conglomerate. This unit includes the Grand Canyon Supergroup, Apache Group, and Troy Quartzite. These rocks were deposited in shallow marine, coastal nonmarine, and fluvial settings. (700-1300)
State Arizona
Name Middle Proterozoic sedimentary rocks
Geologic age Middle Proterozoic
Lithologic constituents
Sedimentary > Clastic > Sandstone (Bed)
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Sedimentary > Clastic > Mudstone > Shale (Bed)
Igneous > Volcanic > Mafic-volcanic > Basalt
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Conglomerate (Bed)
Stratigraphic units Grand Canyon Supergroup, Chuar Group, Unkar Group, Apache Group, Troy Quartzite

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 Cochise - Coconino - Gila - Maricopa - Navajo - Pima - Pinal