LOCATION ONAQUI UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Haploxerolls
TYPICAL PEDON: Onaqui very cobbly loam-rangeland. (Colors are for air-dry soil unless otherwise noted. There is a concentration of gravel on the surface.)
A1--0 to 4 inches; dark brown (10YR 4/3) very cobbly loam, very dark brown (10YR 2/2) moist; moderate fine and very fine granular structure; soft, very friable, slightly sticky, slightly plastic; common very fine and fine and a few medium roots; 25 percent gravel and 25 percent cobbles in the horizon; slightly alkaline (pH 7.6); clear wavy boundary.
A2--4 to 15 inches; brown (10YR 5/3) extremely cobbly loam, dark brown (10YR 3/3) moist; moderate fine and very fine subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common very fine, fine and medium and a few coarse roots; common very fine and few fine tubular pores; 30 percent gravel and 35 percent cobbles; slightly alkaline (pH 7.6); abrupt irregular boundary. (Combined A horizons 10 to 16 inches thick)
R--15 inches; fractured quartzite.
TYPE LOCATION: Tooele County, Utah; 1 mile west of Horse Valley in the southern Sheeprock Mountains; 1,800 feet south and 1,700 feet of the northwest corner of Sec. 33, T. 10 S., R. 5 W.
RANGE IN CHARACTERISTICS: The soil moisture regime is Xeric with the soil moisture control section dry for 45 to 60 consecutive days following the summer solstice. The mean annual soil temperature ranges from 42 to 47 degrees F.
These soils are 10 to 20 inches deep over fractured quartzite. The mollic epipedon is 7 to 16 inches thick. The control section averages 18 to 27 percent clay. Rock fragments range from 35 to 75 percent throughout the profile. The surface is covered with 50 to 90 percent gravel, channers, cobbles, flagstones and stones.
The A horizon has value of 3 to 5 dry, 2 or 3 moist and chroma of 2 or 3. It is very gravelly loam, very cobbly loam, cobbly loam, extremely cobbly loam, extremely cobbly silt loam, or very cobbly silt loam. The A horizon has weak or moderate very fine or fine granular structure in the upper part and weak or moderate very fine or fine subangular blocky structure in the lower part. It is neutral or mildly alkaline in the upper part and mildly to moderately alkaline in the lower part.
Some pedons have a Bw, Bk or C horizons.
COMPETING SERIES: The following list includes soils with a superactive cation-exchange activity class and soils that haven't had an activity class assigned.
Agassiz (UT) soils formed in limestone and the clay ranges to 35 percent.
Alomax (T CA) soils formed in andesite or basalt and are dry in the soil moisture control section for more than 60 consecutive days.
Anatone (WA) soils formed in loess and ash from basalt, andesite, or welded tuff.
Bluecanyon (T OR) soils have 10 to 18 percent clay.
Bocker (WA) soils are dry for 75 to 90 consecutive days following the summer solstice.
Cedaran (NV) soils formed in ignimbrite and the rock fragments are dominantly gravel.
Dipcreek (T ID) soils have a clay range of 12 to 17 percent in the particle size control section and a mean annual soil temperature of 39 to 43 degrees F.
Falula (UT) soils formed in sandstone and conglomerate and are in a 12 to 17 inch precipitation zone.
Foxol (UT) soils are slightly to moderately acid.
Gando (NV) soils have 10 to 18 percent clay in the particle size control section.
Gomine (UT) soils are dry for 60 to 90 consecutive days following the summer solstice.
Grink (NV) soils have 12 to 18 percent clay in the particle size control section and a calcium carbonate equivalent of 5 to 15 percent.
Hogsby (MT) soils have 10 to 20 percent clay in the particle size control section.
Little Pole (UT) soils formed in andesite.
Nayrib (ID) soils have 12 to 18 percent clay in the particle size control section.
Rexmont (UT) soils have a MAST of 37 to 41 degrees F.
Swanner (ID) soils are in a 12 to 16 inch precipitation zone and are dry in the moisture control section for greater than 60 days.
Van Wagoner (UT) soils range to slightly acid reaction and have less than 20 percent clay in particle size control section.
GEOGRAPHIC SETTING: Onaqui soils are on convex windswept mountainsides and ridges at elevations of 5,200 to 10,000 feet. Slopes range from 10 to 60 percent. These soils formed in colluvium and residuum derived dominantly from quartzite and igneous rocks. The mean annual air temperature is 39 to 45 degrees F. Average annual precipitation is 16 to 22 inches. The freeze-free period is 60 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Broad, Flygare, Dateman, and Podmor soils. Broad, Dateman, and Podmor soils have a lithic contact between 20 to 40 inches. Broad soils have argillic horizons and calcic horizons. Flygare soils are more than 60 inches to bedrock and have a mollic epipedon that is more than 20 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for rangeland, wildlife habitat and recreation. Principal vegetation is low sagebrush, bluebunch wheatgrass, phlox and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Western Utah. This series is moderately extensive. The name is that of a mountain range.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Tooele Area, Utah, 1990.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - the zone from the surface to a depth of 15 inches. (A1 and A2 horizon)
Lithic feature - the contact of quartzite bedrock at a depth of 15 inches.
The classification is based on the "Keys to Soil Taxonomy, Eighth Edition, 1998".