LOCATION ILES CO+UTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Calcic Haplustalfs
TYPICAL PEDON: Iles loam, grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 5 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate thin platy structure parting to weak medium granular; soft, very friable, nonsticky and nonplastic; neutral; clear smooth boundary. (3 to 8 inches thick)
BA--5 to 8 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; few thin clay films in tubular pores; neutral; clear smooth boundary. (0 to 5 inches thick)
Bt1--8 to 12 inches; yellowish brown (10YR 5/4) silty clay loam, brown (10YR 4/3) moist; weak fine prismatic structure parting to moderate fine subangular blocky; very hard, firm, sticky and plastic; common thin clay films on peds and in pores; neutral; gradual wavy boundary. (3 to 7 inches thick)
Bt2--12 to 25 inches; yellowish brown (10YR 5/4) silty clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure parting to strong medium angular blocky; very hard, firm, sticky and plastic; many moderately thick clay films on peds and in pores; neutral; clear wavy boundary. (3 to 20 inches thick)
Btk--25 to 29 inches; light yellowish brown (10YR 6/4) silty clay loam, yellowish brown (10YR 5/6) moist; moderate medium subangular blocky structure; slightly hard, friable, sticky and plastic; few thin clay films on peds and in pores, few very fine discontinuous vesicular pores; strongly effervescent; moderately alkaline; clear wavy boundary. (0 to 7 inches thick)
BCk--29 to 36 inches; very pale brown (10YR 7/3) clay loam, light yellowish brown (10YR 6/4) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine discontinuous vesicular pores; violently effervescent; 20 percent calcium carbonate equivalent; moderately alkaline; gradual wavy boundary. (3 to 8 inches thick)
Ck--36 to 60 inches; very pale brown (10YR 8/3) silt loam, very pale brown (10YR 7/4) moist; massive; soft, friable, slightly sticky, slightly plastic; common very fine and fine discontinuous vesicular pores; violently effervescent; 55 percent calcium carbonate equivalent; moderately alkaline.
TYPE LOCATION: Moffat County, Colorado; about 12 miles south and 9 miles west of Craig on Iles mountain; 2,200 feet south and 2,400 feet east of the northwest corner of Sec. 28, T. 5 N, R. 92 W. Latitude 40 degrees, 21 minutes, 22 seconds north. Longitude 107 degrees, 43 minutes, 29 seconds west.
RANGE IN CHARACTERISTICS: Depth to calcareous material normally ranges from 14 to 40 inches, but may be deeper than 40 inches. Thickness of the dark colored A horizon ranges from 3 to 7 inches. Mean annual soil temperature is 42 to 46 degrees F. Mean summer soil temperature is 60 to 65 degrees F. It is estimated that the soil is moist in some part of the moisture control section for about 50 to 70 days when the soil temperature at 20 inches is 41 degrees F. or above.
The A horizon has hue of 5YR through 10YR, value of 4 or 5, 3 or 4 moist, and chroma of 2 through 4. It has up to 10 percent scattered rock fragments on the surface which are mainly pebbles. Reaction ranges from neutral to moderately alkaline.
The Bt horizon has hue of 5YR through 10YR, value of 3 through 7 dry and moist, and chroma of 2 through 6. Texture is typically clay loam, clay, or silty clay loam, but clay may range from 35 to 50 percent. This horizon is commonly noncalcareous, but some pedons are calcareous in the lower part. Reaction ranges from neutral to moderately alkaline.
The C or Bk horizon has hue of 7.5YR through 2.5Y, value of 6 through 8, 5 through 8 moist, and chroma of 2 through 4. It is typically a loam, silt loam, clay loam, silty clay, sandy clay, or gravelly clay. Some thin strata of up to 15 percent pebbles occur. This horizon has greater than 15 percent carbonates throughout, with subhorizons exceeding 40 percent carbonates. The calcic horizon averages 20 to 40 percent calcium carbonate. Reaction ranges from moderate to strongly alkaline.
COMPETING SERIES: These are the Acel (MT), Bario (NM), Burnac (NM), Dandrea (AZ), Echolake (CO), Loghill (CO), Siesta (AZ), Silesca (CO), and Spud (NM) series. Acel soils have cracks wider than 1 cm. at 20 inches. Burnac soils have bedrock at 40 to 60 inches, 15 to 30 percent rock fragments in the surface, and 35 to 55 percent in the substratum. Dandrea and Echolake soils have a paralithic contact at 20 to 40 inches, and Dandrea soils have gravelly Bt horizons. Loghill and Siesta soils lack calcic horizons and are noncalcareous throughout. Silesca soils have a lithic contact at 20 to 40 inches. Spud soils lack carbonates above 40 inches. Bario soils have lower silt content and C horizons with 15 percent or more gravel.
GEOGRAPHIC SETTING: The Iles soils are on undulating mountain ridge tops, benches, toe slopes, and side slopes. Slopes ranges from 2 to 25 percent. They formed in residuum weathered from sandstone and shale with some intermixed aeolian materials. The area is characterized by long, cold winters and short, dry summers. The mean annual precipitation is 16 to 22 inches and is evenly distributed throughout the year. The mean annual soil temperature is 42 to 46 degrees F. The frost-free season is about 75 to 100 days. At the type location, elevation is about 6,400 feet and ranges to 7,200 feet. In Utah, elevation ranges from 7,500 to 8,200 feet in more southerly latitudes.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Work, Regent, and Watrous soils. All have mollic epipedons and lack the high amount of carbonates in the substrata.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: Used for grazing, and some nonirrigated cropland. Native vegetation is mainly Letterman needlegrass, western wheatgrass, mountain brome, and serviceberry.
DISTRIBUTION AND EXTENT: Northwestern Colorado and Southeastern Utah. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Canyonlands Soil Survey Area, Utah; 7/83.
REMARKS: Diagnostic features include an argillic horizon at 8 to 29 inches and a calcic horizon from 29 inches or more. Last updated by the state 12/90.