LOCATION OWEN CREEK WY+MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic Ustic Argicryolls
TYPICAL PEDON: Owen Creek silt loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 6 inches; very dark grayish brown (10YR 3/2) silt loam, very dark brown (10YR 2/2) moist; strong fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; neutral (pH 6.6); gradual smooth boundary. (2 to 8 inches thick)
BA--6 to 10 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure parting to moderate medium granular; slightly hard, very friable, moderately sticky and slightly plastic; many very fine and fine roots; neutral (pH 6.6); gradual smooth boundary. (0 to 5 inches thick)
Bt1--10 to 14 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; strong fine subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; many prominent clay films on faces of peds, in pores, and in root channels; neutral (pH 6.8); clear smooth boundary.
Bt2--14 to 24 inches; yellowish brown (10YR 5/4) silty clay, dark yellowish brown (10YR 4/4) moist; strong medium angular blocky structure; extremely hard, friable, very sticky and very plastic; common very fine and fine roots; many prominent clay films on faces of peds and in pores and root channels; neutral (pH 7.2); clear wavy boundary. (combined thickness of the Bt horizon is 10 to 25 inches)
Btk--24 to 28 inches; pale brown (10YR 6/3) silty clay, dark brown (10YR 4/3) moist; weak medium subangular blocky structure; very hard, friable, moderately sticky and moderately plastic, few very fine roots; few distinct clay films on faces of peds and in root channels; strongly effervescent; calcium carbonate as common fine and medium soft masses; 5 percent shale chips; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 6 inches thick)
Bk--28 to 36 inches; very pale brown (10YR 7/3) silty clay loam, brown (10YR 5/3) moist; massive; very hard, firm, moderately sticky and moderately plastic; violently effervescent; calcium carbonate as common medium and fine soft masses and in seams and threads; 5 percent shale chips; moderately alkaline (pH 8.2); gradual wavy boundary. (6 to 15 inches thick)
Cr--36 to 60 inches; soft, calcareous shale interbedded with thin lenses of soft sandstone.
TYPE LOCATION: Sheridan County, Wyoming; approximately 1,280 feet east and 1,248 feet south of the north 1/4 corner of sec. 3, T. 55 N., R. 89 W. 44 degrees 46 minutes 37 seconds north latitude and 107 degrees 33 minutes 29 seconds west longitude.
RANGE IN CHARACTERISTICS: The mollic epipedon ranges from 7 to 15 inches thick; depth to horizons of continuous carbonate accumulation ranges from 15 to 34 inches. Depth to the paralithic contact and bedrock is typically 28 to 39 inches but may range from 20 to 40 inches. Organic carbon content ranges from 1 to 4 percent in the mollic epipedon and decreases uniformly with increasing depth. The mean annual soil temperature ranges from 32 to 43 degrees F., and the mean summer soil temperature ranges from 40 to 55 degrees F.
The A horizon has hue of 2.5Y through 7.5YR, value of 3 through 5 dry, 2 or 3 moist, and chroma of 0 through 3. Textures are silt loam, loam, or clay loam. Reaction ranges from moderately acid through slightly alkaline. Some pedons may have a surface cover of gravel, cobble, or stone.
The Bt and Btk horizons have hue of 5Y through 7.5YR, value of 3 through 6 dry, 3 through 5 moist, and chroma of 1 through 4. Texture is silty clay, silty clay loam, clay loam, or clay with 35 to 50 percent clay, 30 to 60 percent silt, and 0 to 30 percent sand. The upper part of the Bt is typically part of the mollic epipedon. The Btk is absent in many pedons. Rock fragments consist of shale chips which typically break down on pretreatment. Their fragments range from 0 to 15 percent. Reaction is slightly acid through slightly alkaline but may range to moderately alkaline in the lower part if a Btk is present.
The Bk horizon has hue of 5Y through 7.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 4. Textures are silty clay loam, clay loam, channery clay loam, or channery clay with 27 to 45 percent clay. Calcium carbonate equivalent ranges from about 6 to 14 percent. Reaction is moderately or strongly alkaline. A C horizon occurs in some pedons and is similar to the Bk horizon but lacks the segregated carbonates and high dry value.
The Cr horizon consists of olive, yellowish brown, and brown soft, calcareous shale interbedded with thin, inconsistent lenses of sandstone and siltstone. Few roots penetrate to the paralithic contact which occurs at the soil-bedrock interface; those that do tend to plate out between shale plates within the upper few inches. Some hard sandstone and fissle-like shale lands have been observed in some pedons but are inconsistent and are only a few inches thick.
COMPETING SERIES: These are the Buckskin, Florissant (T), Gothic, Heath, Jerry, Judy, Little Horn, Mayoworth, Parlin, Piltz, and Sneffels series. Buckskin, Gothic, Heath, Jerry, and Parlin soils are very deep. Florissant soils formed in lacustrine deposits influenced by volcanic ash, pumice, and bentonite. Little Horn, Judy and Sneffels soils have a lithic contact at 20 to 40 inches. Mayoworth, Piltz and Sneffels soils are noncalcareous throughout.
GEOGRAPHIC SETTING: Owen Creek soils are on low hills and mountain sideslopes. These soils formed in residuum, alluvium, and colluvium weathered from calcareous shale interbedded with thin lenses of sandstone and siltstone. Slopes are 2 to 35 percent. Elevation ranges from 7,000 to 9,000 feet. The mean annual precipitation is about 20 inches but ranges from about 15 to 25 inches with peak periods occurring during the spring and early summer. The mean annual temperature is about 38 degrees F., but ranges from 33 to 43 degrees F. The frost-free season is estimated to be 60 to 90 days, but frost may occur during any month depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bynum, Echemoor, and Waybe soils and the competing Mayoworth soils. The Bynum soils occur on less stable parts of the landscape and do not have a developed Bt horizon. The Echemoor soils occur in snowdrift areas and have a mollic epipedon greater than 16 inches thick. The Waybe soils occur on steeper or more unstable slopes and are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; slow through rapid runoff depending upon slope; slow permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation consists of big sagebrush, Idaho fescue, thickspike wheatgrass, and mountain brome.
DISTRIBUTION AND EXTENT: The mountain areas of Wyoming and northern Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sheridan County, Wyoming; 1932.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 14 inches (A,BA,Bt1)
Argillic horizon - 10 to 28 inches (Bt1,Bt2,Btk)
Horizons of secondary carbonate accumulation - 24 to 36 inches (Btk, Bk)
Paralithic contact - 36 inches (Cr)
SIR - WY1270
LRR=E