LOCATION TWOCABIN WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Ustic Calciargids
TYPICAL PEDON: Twocabin gravelly loam - on a south facing slope of 1 percent - rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine roots; 20 percent medium and coarse gravel; neutral (pH 7.0); abrupt smooth boundary. (2 to 4 inches thick)
Bt--4 to 11 inches; brown (7.5YR 5/4) very gravelly sandy clay loam, brown (7.5YR 4/4) moist; moderate medium prismatic structure parting to moderate medium angular blocky; slightly hard, friable, moderately sticky and moderately plastic; few fine roots; many prominent clay films on faces of peds, 40 percent medium and coarse gravel; neutral (pH 7.2); clear wavy boundary. (7 to 16 inches thick)
Btk--11 to 20 inches; very pale brown (10YR 7/3) very gravelly loam, light yellowish brown (10YR 6/4) moist; weak medium subangular blocky structure, slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common distinct clay films on faces of peds; violently effervescent, calcium carbonate disseminated and as common fine soft masses; 40 percent fine gravel; moderately alkaline (pH 8.2); clear smooth boundary. (7 to 17 inches thick)
2Bk1--20 to 27 inches; very pale brown (10YR 8/2) loam, very pale brown (10YR 7/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; violently effervescent, calcium carbonate disseminated and as common fine soft masses; less than 5 percent fine gravel; moderately alkaline (pH 8.2); gradual smooth boundary. (5 to 30 inches thick)
2Bk2--27 to 60 inches; very pale brown (10YR 7/3) loam, pale brown (10YR 6/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; violently effervescent, calcium carbonate disseminated and as common fine soft masses and filaments; trace fine and medium gravel; moderately alkaline (pH 8.2).
TYPE LOCATION: Albany County, Wyoming; 1900 feet south, 2000 feet west of the northeast corner, Section 4, T27N, R76W.
RANGE IN CHARACTERISTICS: Depth to the base of the Bt horizon is 11 to 20 inches and depth to the base of the Btk and the nonskeletal substratum is 18 to 32 inches. The mean annual soil temperature is 40 to 45 degrees F. and mean summer soil temperature is 59 to 62 degrees F. The soils are moist in some or all parts of the moisture control section in April, May and early June and dry in all parts for the 90 consecutive days following July 15 in most years.
The A horizon has hue of 10YR or 7.5YR, value of 4 through 6 dry, 3 or 4 moist, and chroma of 3 or 4. Coarse fragments range from 15 to 35 percent pebbles and 0 to 40 percent cobbles. Reaction is neutral or slightly alkaline.
The Bt horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4. The texture of the fine earth is sandy clay loam or clay loam with 20 to 35 percent clay. Coarse fragments range form 25 to 60 percent pebbles and 0 to 20 percent cobbles. Reaction is neutral through moderately alkaline.
The Btk horizon has hue of 10YR or 7.5YR, value of 6 or 7 dry, 5 through 7 moist and chroma of 3 through 6. The texture of the fine earth is loam, clay loam, or sandy clay loam modified with 25 to 65 percent pebbles and 0 to 35 percent cobbles. Calcium carbonate equivalent ranges from 15 to 30 percent. Reaction is moderately alkaline or strongly alkaline.
The 2Bk horizon has hue of 10YR through 5Y, value of 6 through 8 dry, 5 through 7 moist, and chroma of 3 through 6. Texture is loam, clay loam, or sandy clay loam with 18 to 35 percent clay. Coarse fragments are typically absent but range from 0 to 5 percent. Calcium carbonate equivalent ranges from 15 to 35 percent in the upper part and decreases with depth. Reaction is moderately alkaline or strongly alkaline.
COMPETING SERIES: These are the Amalia, Dahlquist, and Lupinto series in the same family and the similar Browtine series. All these soils have skeletal Bk and C horizons. In addition, Lupinto soils have a Bt whose base is less than 10 inches deep. Browtine soils do not have argillic horizons.
GEOGRAPHIC SETTING: Twocabin soils are on broad pediments and associated upland surfaces. Dissection of these surfaces is common. These soils formed in gravelly alluvium overlying soft sedimentary bedrock. Slopes are 6 to 15 percent. Elevations are 7,000 feet to 7,500 feet. The mean annual precipitation is 10 to 14 inches of which about half falls as snow or rain in April, May and early June. The mean annual temperature is 36 to 40 degrees F. The frost-free season ranges from 85 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lahtida and Pinelli soils. Lahtida soils are moderately deep and contain over 35 percent clay in the Bt horizon. Pinelli soils contain over 35 percent clay in the Bt and are nonskeletal throughout.
DRAINAGE AND PERMEABILITY: Well drained; runoff is slow and medium; permeability is moderate.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation consists of black sagebrush, bluebunch wheatgrass, western wheatgrass, mutton bluegrass, and needleandthread.
DISTRIBUTION AND EXTENT: Twocabin soils are in the south central part of Wyoming on pediments of the Laramie range. MLRA 33, 34. They are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Albany County (Albany County Area), Wyoming, 1991.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A)
Argillic horizon - 4 to 20 inches (Bt, Btk);
Calcic horizon - 11 to 60 inches (Btk,2Bk1,2Bk2);
Lithologic discontinuity - 20 inches (2Bk1);
These soils have a frigid temperature regime and an aridic moisture regime that borders on an ustic regime.
SIR - WY0904
LRR=D