LOCATION TIGIWON COEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Ustic Calciargids
TYPIFYING PEDON: Tigiwon gravelly sandy loam in pasture. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; grayish-brown (10YR 5/2) gravelly sandy loam dark grayish brown (10YR 4/2) when moist; moderate, fine, granular structure; soft very friable; 20 percent gravel; neutral; gradual wavy boundary 2 to 4 inches thick
B2t--3 to 10 inches; brown (7.5YR 5/3) gravelly sandy clay loam, brown (7.5YR 4/3) when moist; moderate, medium, prismatic structure that parts to moderate medium subangular blocks; hard very friable; common patchy clay films on horizontal and vertical faces of peds; approximately 25 percent gravel; noncalcareous; mildly alkaline; clear wavy boundary 4 to 8 inches thick.
B3ca--10 to 13 inches, pale-brown (10YR 6/3) gravelly sandy loam, brown (10YR 5/3) when moist; weak medium prismatic structure that parts to weak medium subangular blocks; slightly hard, very friable; few thin patchy clay films, principally on the vertical faces of peds; 25 percent gravel; visible secondary calcium carbonate occurring as concretions and in thin seams and streaks; calcareous; moderately alkaline; gradual, wavy boundary 2 to 3 inches thick.
IICca--13 to 60 inches, sand and gravel; moderate accumulation of secondary carbonate in the upper part, decreasing as depth increases.
TYPE LOCATION: Chaffee County, Colorado; NW1/4 Sec. 32, T. 50 N., R. 8 E.
RANGE IN CHARACTERISTICS: Depth to uniformly calcareous material normally ranges from 6 to 12 inches, but is not shallower than the upper 3 inches of the B2t horizon. Typically the solum extends to the IIC horizon but thin C horizons may occur above the IIC horizon in some pedons. Depth to the sandy-skeletal IIC horizon ranges from 10 to 20 inches. Depth to the base of the argillic horizon ranges from 7 to 12 inches. Rock fragments range from 15 to 35 percent by volume in a major part of the solum and C horizon above the IIC horizon and are dominantly less than 3 inches in diameter. Reaction above the B3ca horizon ranges from neutral to moderately alkaline.
The A horizon has hue of 2.5Y through 7.5YR, value of 5 through 7 dry 3 through 6 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 sandy clay loam but clay averages 18 to 35 percent in the fine earth fraction.
The IIC horizon has hue of 2.5Y through 7.5YR. It ranges from moderately to very strongly alkaline and has about 3 to 14 percent calcium carbonate equivalent of the fine earth.
COMPETING SERIES: These are the Bosler, Millburne, Platoro and Relsob series. Bosler soils have solums thicker than 12 inches to the base of the argillic horizon and have sandyskeletal IIC horizons below depth of 20 inches; Millburne soils have weakly cemented calcic horizons and have sandy-skeletal IIC horizons below depth of 20 inches. Platoro soils have solums more than 12 inches thick to the base of the argillic horizon, have sandy-skeletal IIC horizons below depth of 20 inches and are calcareous above the upper 3 inches of the B2t horizon. Relsob soils lack continuous horizons of secondary calcium carbonate.
GEOGRAPHIC SETTING: These soils are on old high terraces or alluvial fans. Slope gradient typically ranges from 2 to 10 percent. The soils formed in mixed alluvial parent materials derived from a variety of rock sources. At the type location the average annual precipitation is approximately 11 inches with peak periods of precipitation in the spring and summer. Mean annual temperature is 43 degrees F., and mean summer temperature is 58 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bosler soils and the Turret soils. Turret soils have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well-drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used both as pastureland and as irrigated cropland. Native vegetation is mainly pinon and juniper with an understory of blue grama, three awn, and sand dropseed.
DISTRIBUTION AND EXTENT: Mountain valleys of central and southern Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Chaffee County, Colorado 1974
REMARKS: OSED scanned by and cleaned up by Colorado. Last revised by state on 8/74.