LOCATION CHAIN COTentative Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Aridic Haplustalfs
TYPICAL PEDON: Chain very cobbly clay loam - Pinyon-Juniper Woodland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; brown (7.5YR 5/2) very cobbly clay loam, dark brown (7.5YR 3/2) moist; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; 20 percent pebbles and 15 percent cobbles; mildly alkaline (pH 7.8); clear smooth boundary. (3 to 8 inches thick)
Bt1--4 to 11 inches; brown (7.5YR 5/2) very cobbly clay, dark brown (7.5YR 4/2) moist; strong very fine and fine angular blocky structure; hard, firm, very sticky and very plastic; few faint clay films on ped faces; 20 percent pebbles and 25 percent cobbles; neutral (pH 7.2); clear smooth boundary. (4 to 12 inches thick)
Bt2--11 to 18 inches; brown (10YR 5/3) very cobbly clay, dark brown (10YR 4/3) moist; strong fine and medium angular blocks parting to subangular blocky structure; hard, firm, very sticky and very plastic; many prominent clay films on ped faces; 10 percent pebbles and 40 percent cobbles; neutral (pH 7.2); clear smooth boundary. (5 to 15 inches thick)
Bt3--18 to 26 inches; brown (7.5YR 5/4) extremely cobbly clay, dark brown (7.5YR 4/4) moist; strong fine and medium subangular blocks parting to angular blocky structure; hard, firm, very sticky and very plastic; common distinct clay films on ped faces; 20 percent pebbles and 50 percent cobbles; neutral (pH 6.8); clear smooth boundary. (6 to 20 inches thick)
C--26 to 60 inches; light brown (7.5YR 6/4) extremely cobbly clay loam, brown (7.5YR 4/4) moist; massive; hard, firm, sticky and plastic; 25 percent pebbles and 50 percent cobbles; neutral (pH 6.8).
TYPE LOCATION: Delta County, Colorado; 1,000 feet west of Todd Reservoir in the NE 1/4 of the NE 1/4 of Sec. 5, T. 15 S., R. 91 W. Latitude 38 degrees, 46 minutes, 59 seconds north; Longitude 107 degrees, 34 minutes, 42 seconds west.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 49 to 52 degrees F. Mean summer soil temperature ranges from 56 to 62 degrees F. The solum ranges from 20 to 40 inches thick. Depth to bedrock is 60 or more inches.
The A horizon has hue of 10YR through 5YR, value of 4 through 6, and 2 through 4 moist, with chroma of 2 through 4. It has 10 to 40 percent cobble coarse fragments on the surface. Rock fragments in this horizon range from 20 to 45 percent by volume.
The Bt horizon has hue of 10YR through 5YR, value of 5 or 6, and 4 or 5 moist, with chroma of 2 through 6. Texture is clay loam, clay, or silty clay with clay ranging from 36 to 50 percent. Coarse fragments range from 40 to 75 percent with cobbles dominant.
The C horizon has hue of 10YR through 5YR, value of 5 through 7, and 4 through 6 moist, with chroma of 2 through 6. Texture is clay loam, clay or silty clay. Coarse fragments range from 30 to 80 percent.
COMPETING SERIES: There are no competing series. The closely related Cochiti and Devisadero soils have mixed mineralogy.
GEOGRAPHIC SETTING: Chain soils are on the tops and hill slopes of mesas and ridges. Slopes are 15 to 40 percent. This soil formed in residuum and colluvium derived from shale with an overburden derived from andesite and breccia. Elevation ranges from 7,000 to 7,600 feet. The mean annual precipitation ranges from 14 to 18 inches. The mean annual temperature ranges from 47 to 50 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Morop and Showalter series. The Morop and Showalter soils have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; slow permeability.
USE AND VEGETATION: This soil is used for livestock grazing, recreation, and wildlife habitat. Principal native vegetation is pinyon pine, Utah juniper, big sagebrush, pricklypear cactus, cheatgrass, Indian ricegrass, muttongrass, bottlebrush squirreltail, and junegrass.
DISTRIBUTION AND EXTENT: West Central, Colorado. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Grand Mesa-West Elk Soil Survey Area, Delta County, Colorado, 1984. The soil name is from a range of mountains in the area.
REMARKS: Diagnostic features include an Argillic horizon from 4 to 26 inches. An Ochric epipedon is a result of thin surface layers not diagnostic for a mollic epipedon. Last updated by the state 3/93.