LOCATION WESTCREEK COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Alfic Argiustolls
TYPICAL PEDON: Westcreek gravelly coarse sandy loam - open forest (Colors are for dry soil unless otherwise noted.)
A1--0 to 12 inches; grayish brown (10YR 5/2) gravelly coarse sandy loam, very dark grayish brown (10YR 3/2) moist; strong very fine granular structure; soft, very friable; 15 percent fine and very fine angular granite gravel; neutral; clear smooth boundary. (6 to 14 inches thick)
A2--12 to 18 inches; light brownish gray (10YR 6/2) gravelly coarse sandy loam, grayish brown (10YR 5/2) moist; weak medium platy structure that parts to very fine granules; slightly hard, very friable; vesicular; 20 percent fine and very fine angular granite gravel; neutral; clear smooth boundary. (4 to 12 inches thick)
A&B--18 to 24 inches; light brownish gray (10YR 6/2) and brown (10YR 5/3) gravelly coarse sandy loam, grayish brown (10YR 5/2) and dark brown (10YR 4/3) moist; weak fine subangular blocky structure; very hard, very friable; this horizon consists of nodules and seams of material like that of the underlying horizon embedded in a matrix like that of the overlying horizon; 25 percent fine and very fine angular granite gravel; neutral; gradual wavy boundary. (3 to 12 inches thick)
B2t--24 to 48 inches; brown (10YR 5/3) gravelly sandy clay loam, dark brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, very friable, slightly sticky, slightly plastic; peds are extremely hard, friable; continuous clay films on peds and in root channels and pores; 30 percent fine and very fine angular granite gravel; slightly acid; gradual wavy boundary. (10 to 30 inches thick)
B3--48 to 54 inches; brown (10YR 5/3) gravelly coarse sandy loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, very friable; peds are extremely hard, very friable; thin patchy clay films on peds and in some root channels and pores 30 percent fine and very fine angular granite gravel; neutral; gradual wavy boundary. (5 to 7 inches thick)
C--54 to 60 inches; brown (10YR 5/3) gravelly coarse sandy loam; dark brown (10YR 4/3) moist; extremely hard, very friable, 30 percent fine and very fine angular granite gravel; neutral.
TYPE LOCATION: Douglas County, Colorado; along State Highway 67 approximately 300 feet east of the entrance to Woodbine Lodge; Sec. 6, T. 8 S., R. 68 W.
RANGE IN CHARACTERISTICS: These soils typically are noncalcareous to depths of more than 60 inches and are noncalcareous to depths of more than 40 inches in all pedons. Base saturation typically is more than 80 percent and ranges from 60 to 100 percent in all subhorizons of the argillic horizon. Depth to the top of the argillic horizon is less than 24 inches, and depth to the base of the argillic horizon ranges from 15 to 50 inches. Rock fragments range from 15 to 35 percent in a major part of the solum and in the C horizon and are mainly less than 3 inches in diameter but range from 1/8 to 10 inches in diameter. Within the sand fraction a high percentage is medium and coarser angular sand which has a large proportion of flat bearing surfaces. The solum and C horizons range from medium acid through mildly alkaline. The mean annual soil temperature is 45 degrees F., and the mean summer soil temperature is 64 degrees F.
The A1 horizon has hue of 2.5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3.
The A2 horizon has hue of 2.5Y through 7.5YR, value of 5 through dry, 4 through 7 moist, and chroma of 1 through 4.
The B2t horizon has hue of 2.5Y through 7.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 6. It is typically gravelly coarse sandy clay loam and has 18 to 30 percent clay and 40 to 75 percent sand.
The C horizon has hue of 2.5Y through 7.5YR. It is gravelly coarse sandy loam or loam with less than 18 percent clay and more than 35 percent fine or coarser sand.
COMPETING SERIES: These are the Crowfoot, Kelvin, Redtom, and Tomah series. Crowfoot soils have less than 15 percent rock fragments. Kelvin soils are calcareous in the lower part of the solum or in the C horizons and have continuous subhorizons of secondary calcium carbonate accumulation. Redtom and Tomah soils have discontinuous argillic horizons in which silicate clay is accumulating in lamellae.
GEOGRAPHIC SETTING: Westcreek soils are on alluvial fans, valley side slopes, or hills and ridges. Slope gradients range from 5 to 30 or more percent. The soils formed in parent sediments weathered and locally transported from beds of Dawson arkose or granite rock. At the type location the average annual precipitation is 17 inches, with peak periods of precipitation in the spring and early summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Crowfoot and Tomah soils.
DRAINAGE AND PERMEABILITY: Well drained; medium to slow runoff; moderate permeability.
USE AND VEGETATION: These soils are used for forestry, native pasture, and recreation. Native vegetation is mainly scattered ponderosa pine, oakbrush, and grasses.
DISTRIBUTION AND EXTENT: The foothill areas of east-central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Douglas County, Colorado, 1974.
REMARKS: OSED scanned by NSSQA and cleaned up by Colorado. Last revised by state 8/74.