LOCATION MCCORT WYTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Haplocryolls
TYPICAL PEDON: McCort gravelly sandy loam - rangeland (Colors are for air-dry soil unless otherwise stated.)
A1--0 to 6 inches; brown (7.5YR 4/2) gravelly sandy loam, very dark brown (7.5YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky, slightly plastic; many fine roots; 15 percent gravel; neutral (pH 7.0); clear wavy boundary. (3 to 8 inches thick)
A2--6 to 12 inches; brown (7.5YR 4/2) gravelly sandy loam, dark brown (7.5YR 3/2) moist; weak coarse to medium subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; many fine and medium roots; 15 percent gravel; neutral (pH 7.2); clear wavy boundary. (3 to 18 inches thick)
Bw--12 to 21 inches; reddish brown (5YR 5/3) gravelly sandy loam, reddish brown (5YR 4/3) moist; moderate coarse to fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; common fine and medium roots; 20 percent gravel; neutral (pH 7.2); clear wavy boundary.
C1--21 to 31 inches; light reddish brown (5YR 6/3) very gravelly sandy loam, reddish brown (5YR 4/3) moist; massive; slightly hard, friable, slightly sticky, nonplastic; few fine and medium roots; 55 percent gravel; neutral (pH 7.2); gradual wavy boundary.
C2--31 to 60 inches; reddish brown (5YR 5/3) extremely cobbly sandy loam, reddish brown (5YR 4/3) moist; massive; loose, very friable, slightly sticky, nonplastic; 15 percent cobble, 10 percent stone, 40 percent gravel; neutral (pH 7.2).
TYPE LOCATION: Sweetwater County, Wyoming; about 40 miles south of Rock Springs; along the east side of trail on Pine Mountain, 500 feet south of center of Sec. 9, T12N, R103W; Red Creek Ranch USGS quad; approximate lat. 41 degrees 02 minutes 00 seconds N. and long. 109 degrees 00 minutes 59 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: Udic moisture regime bordering on ustic.
Mean annual soil temperature: 42 to 44 degrees F
Mean summer soil temperature: 55 to 58 degrees F
Depth to cambic horizon: 6 to 26 inches
Thickness of the mollic epipedon: 7 to 15 inches
Particle-size control section (weighted average):
Clay content: 10 to 18 percent
Sand content: >35 percent fine or coarser sand
Rock fragments: 35 to 65 percent quartzite gravel and 0 to 3 percent cobbles
A horizons:
Hue: 7.5YR or 10YR
Value: 2 to 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: gravelly sandy loam or gravelly coarse sandy loam
Rock fragments: 15 to 50 percent gravel, 0 to 3 percent cobble
Reaction: slightly acid or neutral
Bw horizon:
Hue: 5YR or 7.5YR
Value: 4 or 5 dry or moist
Chroma: 3 or 4 dry or moist
Rock fragments: 15 to 50 percent gravel, 0 to 3 percent cobble
Reaction: slightly acid or neutral
C horizons:
Hue: 5YR or 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4 dry or moist
Texture: extremely cobbly sandy loam, very gravelly sandy loam, or very gravelly coarse sandy loam
Rock fragments: 35 to 60 percent gravel and 15 to 25 cobble and stone
Reaction: slightly acid or neutral
COMPETING SERIES: Current competitors are the Antrobus, Grafen, Greyback, Handran, Maurice, Sebud, Supervisor, Surdal, Teemat, Thornburgh, Tiban, Tineman, and Vanwirt series.
Antrobus, Sebud, Tiban, Vanwirt: greater than 18 percent clay in the particle-size control section
Grafen: moderately deep to a paralithic contact
Greyback, Teemat: has horizons with secondary calcium carbonate accumulations
Handran: lack a cambic horizon and formed in glacial materials weathered from granite
Maurice: has thicker cambic horizon and does not have 5YR hues in the B or C horizons
Parachute, Supervisor, Surdal: moderately deep to a lithic contact
Thornburgh: rock fragments are primarily channers and it does not have 5YR hues in the B and C horizons
Tineman: has a lithologic discontinuity with sandy-skeletal materials and does not have 5YR hues.
GEOGRAPHIC SETTING:
Parent material: gravelly slope alluvium derived from quartzitic conglomerate
Landform: gently sloping to very steep alluvial fans and mountain sides
Slopes: 2 to 55 percent
Elevation: 8,500 to 9,800 feet
Mean annual precipitation: 15 to 20 inches
Mean annual temperature: 39 degrees to 42 degrees F.
mean summer temperature: 54 degrees to 58 degrees F.
frost-free period: 50 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Scout, Teeler, and Teeman soils. Scout soils lack the mollic epipedon and have cambic horizons. Teeler soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained, medium to high runoff, moderately rapid permeability.
USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The native vegetation is big sagebrush, black sagebrush, letterman needlegrass, foxtail barley, Idaho fescue, and spike fescue.
DISTRIBUTION AND EXTENT: Present known distribution limited to southwestern Wyoming. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Sweetwater County (Red Creek Watershed area), Wyoming; 1974. The name is taken from the name of a local draw.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 10 to 40 inches. (A2 through C2 horizons)
Mollic epipedon: The zone from 0 to 12 inches. (A1 and A2 horizons)
Cambic horizon: The zone from 12 to 21 inches. (Bw horizon)
These soils were formerly classified as Chernozems. A paper revision and update of the series was made by MO6 August 2000. The classification was changed from Typic Cryoborolls to Ustic Haplocryolls. Format and horizonation designations were updated.
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomic Version: Second Edition of Soil Taxonomy 1999.