LOCATION SILVERHEELS COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Argicryolls
TYPICAL PEDON: Silverheels sandy loam, 2 percent slope in grassland at an elevation of 9,860 feet. (Colors are for dry soil unless otherwise noted.) Described on August 22, 2000.
A--0 to 10 inches; dark brown (7.5YR 3/3) sandy loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; 5 percent gravel, 1 percent cobbles; neutral (pH 6.8); clear smooth boundary. (10 to 12 inches thick)
Bt1--10 to 15 inches; brown (7.5YR 4/4) gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; hard, very firm, slightly sticky and slightly plastic; few faint clay films on faces of peds; 25 percent gravel, 5 percent cobbles; neutral (pH 6.8); clear smooth boundary.
Bt2--15 to 21 inches; brown (7.5YR 4/4) gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; very hard, very firm, moderately sticky and moderately plastic; few distinct clay films on faces of peds; 25 percent gravel, 5 percent cobbles; neutral (pH 7.0); clear wavy boundary.
Bt3--21 to 47 inches; brown (7.5YR 5/4) extremely gravelly sandy clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; very hard, very firm, very sticky and moderately plastic; few distinct clay films on faces of peds; 50 percent gravel, 20 percent cobbles; neutral (pH 7.2); clear wavy boundary. (Combined thickness of the upper Bt horizons: 30 to 40 inches)
Bt4--47 to 60 inches; strong brown (7.5YR 5/6) extremely gravelly sandy loam; strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; hard, very firm, slightly sticky and slightly plastic; few faint clay films on faces of peds; 50 percent gravel, 20 percent cobbles; neutral (pH 7.0).
TYPE LOCATION: Park County, Colorado; north of Como; in the north half of sec. 28, T. 8 S., R. 76 W.; Como USGS quad.; latitude 39 degrees, 19 minutes, 40 seconds N., longitude 105 degrees, 53 minutes, 31 seconds W. (estimated), NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is usually dry in some part in early summer, moist in some or all parts in late July and August, and intermittently dry in fall; ustic regime.
Mean annual soil temperature: 37 to 41 degrees F.
Mean summer soil temperature: 51 to 58 degrees F.
Thickness of the mollic epipedon: 7 to 11 inches
Depth to argillic horizon: 7 to 11 inches
Rock fragment lithology: mainly granite and gneiss
Particle-size control section (weighted average):
Clay content: 20 to 30 percent
Rock fragment content: 35 to 50 percent
A horizon
Hue: 10YR or 7.5YR
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3 dry; 2 or 3 moist
Clay content: 10 to 18 percent
Rock fragment content: 5 to 15 percent
Fragment size and content: 5 to 13 percent gravel, 0 to 2 percent cobbles
Organic matter content: 2.0 to 4.0 percent
Bt horizon, upper part
Hue: 10YR or 7.5YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 4 to 6 dry; 4 to 6 moist
Texture: gravelly sandy clay loam, very gravelly sandy clay loam, extremely gravelly sandy clay loam
Clay content: 20 to 30 percent
Rock fragment content: 15 to 75 percent
Fragment size and content: 10 to 65 percent gravel, 5 to 20 percent cobbles
Organic matter content: 0.0 to 0.5 percent
Bt horizon, lower part
Hue: 10YR or 7.5YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 4 to 6 dry; 4 to 6 moist
Clay content: 10 to 18 percent
Rock fragment content: 35 to 75 percent
Fragment size and content: 30 to 65 percent gravel, 5 to 20 percent cobbles
COMPETING SERIES: These are the
Bassel,
Blaine,
Bowen,
Fingerrock,
Fornor
Fourmile,
Geertsen,
Hoodle,
Hungryhill,
Lagarita,
Lambe,
Libeg,
Nathale,
Nathrop,
Norriston,
Quander,
Ratiopeak,
Spanpeak, and
Woodhall series.
The Bassel and Geertsen soils are deep to a lithic contact.
The Blaine, Bowen, Hungryhill, Nathale, Nathrop and Woodhall soils are moderately deep to a lithic contact.
The Fingerrock soils have sandy-skeletal horizons below the argillic horizon.
The Fornor, Hoodle, Lagarita, Lambe, and Ratiopeak soils have accumulations of secondary carbonates.
The Fingerrock, Fourmile, Norriston, and Spanpeak soils have sandy-skeletal horizons below the argillic horizon.
The Libeg soils have an ustic soil moisture regime that borders udic, and are more moist in the moisture control section in early summer.
The Quander soils have rock fragments of breccia, trachyte, andesite and other volcanic rocks.
GEOGRAPHIC SETTING:
Parent material: outwash, derived mainly from granite and gneiss
Landform: outwash terraces
Slopes: 1 to 5 percent
Elevation: 9,500 to 10,000 feet
Mean annual temperature: 35 to 39 degrees F.
Mean annual precipitation: 14 to 17 inches
Precipitation pattern: Monthly precipitation is lowest in winter and greatest in July and August.
Frost-free period: 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cablon, Platdon, and Monahan series. The Cablon soils border an aridic moisture regime and are on outwash terraces at lower elevations. The Platdon soils are very poorly drained and are on flood plains. The Monahan soils have higher clay content and are on pediments.
DRAINAGE AND PERMEABILITY: Well drained, moderate permeability
USE AND VEGETATION: These soils are used for hayland. Native vegetation consists mainly of western wheatgrass, slimstem muhly, sleepygrass, prairie Junegrass, blue grama, Parry's oatgrass, mountain muhly, and Arizona fescue.
DISTRIBUTION AND EXTENT: Central Colorado; LRR E, MLRA 48B; small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Park County, Colorado, Teller-Park soil survey area, Colorado, 2010. The name is taken from Silverheels Creek nearby.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to below 60 inches.
Particle-size control section: The zone from 10 to 30 inches. (Bt1, Bt2, Bt3 horizons)
Mollic epipedon: The zone from 0 to 10 inches. (A horizon)
Argillic horizon: The zone from 10 to 60 inches and below. (Bt1, Bt2, Bt3, Bt4 horizons)
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomic Version: Classified according to Keys to Soil Taxonomy, 11th Edition, 2010.