PP - Permian and Pennsylvanian Sedimentary Rocks

(Includes Coconino Sandstone, Supai Formation, and Naco Formation)

Coconino Formation

Approximate Thickness

0-650 feet.

Lithologic Description

Sandstone, very fine to fine-grained, white to very pale orange, grayish-orange; characterized by large-scale crossbeds, weakly to well cemented by silica and calcite.

Water-Bearing Characteristics

Principal unit of the regional aquifer in the Plateau uplands area from the eastern boundary to the Mogollon Rim; well yields may be as much as 1,000 gallons per minute in areas of fracturing and/or faulting; well yields in other areas are probably only a few hundred gallons per minute; yields water to springs in several of the major drainages along the Mogollon Rim; the water is of acceptable chemical quality.

Supai Formation

Approximate Thickness

Upper member: 0-625 feet. Middle member: 0-300 feet. Lower member: 0-1,000 feet.

Lithologic Description

Upper member: Sandstone and siltstone. Sandstone, very fine to coarse-grained, reddish-orange to light-brown and moderate-reddish-brown, friable; beds are thick and massive, some calcareous. Siltstone, pale-reddish-brown; average bed thickness 6 to 8 feet.

Middle member: Siltstone, mudstone, intercalated with conglomerate, sandstone, and some limestone; siltstone, mudstone, sandstone, fine-grained, pale- to dark-reddish-brown, thin-bedded. Conglomerate, dolomitic, light-brownish-gray to medium-gray limestone pebbles, well rounded, in a pale-red to reddish-brown siltstone matrix. At the base of the unit a limestone bed, dark-pinkish-gray, aphanitic, sandy, and cross-laminated.

Lower member: Sandstone, siltstone. Upper unit sandstone with intercalated siltstone and some limestone, lower unit siltstone with some shaley mudstone and intercalated limestone conglomerate, limestone, and sandstone. Sandstone, siltstone, and mudstone, fine-grained, pale- to dark-reddish-brown, thin- to thick-bedded, cross-laminated. Limestone, light-bluish-gray to light-brownish-gray, aphanitic to coarsely crystalline. At the base of the unit, chert breccia or limestone conglomerate.

Water-Bearing Characteristics

Principal unit of the regional aquifer in the Sedona area; well yields range from a few gallons per minute to a few hundred gallons per minute in areas of fracturing and faulting; most of the base flow in the upper reaches of Oak Creek is derived from this unit; the water is of acceptable chemical quality.

Naco Formation

Approximate Thickness

0-475 feet.

Lithologic Description

Mainly siltstone and sandstone, fine-grained, red to gray; contains reddish sandy shale and chert breccia at the base; includes interbeds of gray to pink arenaceous limestone.

Water-Bearing Characteristics

Yields water to Fossil Springs at 18,600 gallons per minute along the southern boundary of the area; the water is of acceptable chemical quality.

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