Collapse feature 236, Mohawk Canyon, Coconino Co., Arizona, USAi

Regional Level Types
Collapse feature 236	Pipe
Mohawk Canyon	Canyon
Coconino Co.	County
Arizona	State
USA	Country

Age: Phanerozoic (251.902 - 298.9 Ma)

Lithology: Sedimentary rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Age: Paleozoic (272.95 - 315.2 Ma)

Stratigraphic Name: Hermit Formation; Supai Group; Schnebly Hill Formation; Naco Group

Description: Interbedded sandstone, shale, and limestone usually characterized by ledgy outcrops. Orange to reddish sandstone forms cliffs near Sedona. This unit includes Supai Group and Hermit Shale in northern Arizona and Naco Group in southern Arizona. It was deposited in coastal-plain to shallow-marine settings during time of variable and changing sea level. Rocks of this map unit in southern Arizona may be in part equivalent to Permian rocks of map unit P in central and northern Arizona. (280-310 Ma)

Comments: Original map source: Arizona Geological Survey, DI-8 Geologic Map of Arizona, Digital Spatial data for the Geologic Map of Arizona, v. 3.0, edited by S.M. Richard and S.M. Kneale, 2002, 10 p., 2 DOS HD disks. Arc/INFO export file (.e00) format, scale 1:1,000,000.

Lithology: Major:{sandstone,shale,limestone}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Age: Carboniferous (298.9 - 330.9 Ma)

Stratigraphic Name: Wescogame Formation; Manakacha Formation; Watahomigi Formation

Description: Wescogame Formation—Light-red, pale-yellow, and light-gray upper slope unit and lower cliff unit. Upper slope unit consists mainly of dark-red, fine-grained siltstone and mudstone interbedded with light-red, coarse-grained, calcareous sandstone and dolomitic sandstone, siltstone, mudstone, and conglomerate. Lower cliff unit consists mainly of light-red to gray, high-angle, large- and medium-scale, tabular-planar, cross-bedded sandstone and calcareous sandstone sets as much as 40 ft (12 m) thick. Includes interbedded dark-red, thin-bedded siltstone in upper part of cliff. Cross-bed sets contain large footprints of four-footed vertebrate animals in eastern part of map area. Unconformable contact with underlying Manakacha Formation marked by unconformity of erosion channels as much as 80 ft (24 m) deep in western part of map area, and less than 30 ft (10 m) deep in eastern part of map area. Channels commonly filled with limestone/chert conglomerate. The Wescogame thickens slightly from west to east, averaging about 130 ft (40 m) in western part of map area and about 150 ft (45 m) in eastern part Manakacha Formation—Light-red, white, and gray upper slope unit and lower cliff unit of sandstone, calcareous sandstone, dark-red siltstone, and gray limestone. Upper slope unit consists mainly of shaley siltstone and mudstone with minor interbedded, thin-bedded limestone and sandstone. Carbonate content of upper slope unit increases westward to form numerous ledge-forming, thin- and medium-bedded limestone beds. Upper slope unit is about 100 ft (30 m) thick in eastern half of map area, decreasing to less than 60 ft (18 m) thick in western half. Lower cliff unit is dominated by grayish-red, medium- to thick-bedded, cross-bedded calcareous sandstone, dolomite, and sandy limestone. Lower cliff unit is about 60 ft (18 m) thick in eastern part of map area, thickening to about 100 ft (30 m) in western part. Carbonate content of lower cliff unit increases westward across map area, forming numerous gray limestone ledges. Unconformable erosional contact between the Manakacha and underlying Watahomigi Formation approximately marked at base of lower sandstone cliff of the Manakacha; erosional relief generally less than 3 ft (1 m) and wavy unconformable surface. Overall thickness averages about 200 ft (60 m) throughout map area Watahomigi Formation—Gray and purplish-red, slope-forming limestone, siltstone, mudstone, and conglomerate. Forms an upper ledge/slope unit and a lower slope unit. Upper ledge/slope unit consists of alternating gray, thin-bedded cherty limestone ledges interbedded with purplish-gray siltstone and mudstone; limestone beds contain Lower Pennsylvanian conodont fossils (Martin and Barrick, 1999); red chert lenses and nodules common. Includes limestone chert-pebble conglomerate at base, locally containing Lower Pennsylvanian fossils. Upper ledge/slope unit averages about 70 ft (21 m) thick throughout map area. Lower slope unit consists mainly of purplish-red mudstone and siltstone, interbedded with thin-bedded, aphanitic to granular limestone in upper part with red chert veins and nodules. Conodonts in lower thin limestone beds are Upper Mississippian (Martin and Barrick, 1999). Unit includes purple siltstone and gray limestone interbedded with conglomerate that fill small erosion channels cut into either Surprise Canyon Formation (Ms) or Redwall Limestone (Mr). Purple shale and mudstone of lower slope unit unconformably overlies the gray Redwall in majority of map area. Contact with the Surprise Canyon is often based on color change from purple mudstone of the Watahomigi to dark-red mudstone of the Surprise Canyon. Unit averages about 100 ft (30 m) thick along eastern edge of map area, thickening to about 200 ft (60 m) along western edge

Reference: Billingsley, G.H. Geologic Map of the Grand Canyon 30' x 60' Quadrangle, Coconino and Mohave Counties, Northwestern Arizona. USGS Geologic Investigations Series I-2688. [34]