LOCATION MERGEL COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Torriorthentic Haplustolls
TYPICAL PEDON: Mergel channery loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 9 inches; grayish brown (10YR 5/2) channery loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium granular structure; soft, very friable, slightly sticky and slightly plastic; 20 percent angular channers and cobbles; mildly alkaline; clear wavy boundary. (7 to 15 inches thick)
AC--9 to 12 inches; light brownish gray (10YR 6/2) channery clay loam, dark grayish brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, friable, sticky and plastic; 20 percent angular channers and cobbles; calcareous; moderately alkaline; clear wavy boundary. (0 to 9 inches thick)
C1ca--12 to 22 inches; pale brown (10YR 6/3) very channery light clay loam, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, sticky and plastic; 30 percent angular channers, 15 percent flagstones; calcareous, calcium carbonate coatings as pendants on rocks; moderately alkaline; clear wavy boundary. (7 to 15 inches thick)
C2ca--22 to 50 inches; light brownish gray (10YR 6/2) very channery heavy loam, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 30 percent channers and 15 percent flagstones; calcareous, calcium carbonate coatings as pendants on rocks; moderately alkaline; clear wavy boundary. (20 to 36 inches thick)
C3--50 to 60 inches; brown (10YR 4/3) very channery light loam, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; 35 percent angular channers and cobbles, 15 percent flagstones; calcareous; moderately alkaline.
TYPE LOCATION: Rio Blanco County, Colorado, 2,290 feet south and 1,300 feet east of the NW corner of Sec. 32, T. 2 N., R. 93 W.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon ranges from 7 to 15 inches. The depth to calcareous material ranges from 0 to 12 inches. Content of organic carbon ranges from .7 to 1.5 percent and decreases uniformly with increasing depth. The soils are 90 to 100 percent base saturated. The control section is channery or very channery loam or clay loam, with the fine earth fraction ranging in clay from 18 to 35 percent. Rock fragments range from 35 to 80 percent and are usually channers or flagstones, but are gravel or cobbles in some pedons.
The A1 horizon has hue of 2.5Y or 10YR, value of 4 or 5 dry, 2 or 3 moist, and chroma, and chroma of 2 or 3. It is mildly or moderately alkaline. It is calcareous in some pedons. Usually this horizon has granular structure but it has weak subangular blocky structure in some pedons. It is soft or slightly hard.
The Cca horizon has hue of 2.5Y or 10YR. It is moderately alkaline or strongly alkaline (pH 8.0 to 8.6). The calcium carbonate equivalent ranges from approximately 4 to 12 percent.
COMPETING SERIES: These are the Abarca and Shrine series. Abarca soils have sandy-skeletal material above a depth of 40 inches. Shrine soils have less than 35 percent rock fragments.
GEOGRAPHIC SETTING: Mergel soils are on concave mountain side slopes, hills, and ridges. Slope gradients range from about 3 to 65 percent. The soils formed in allvuial fan or facial sediments derived from crystalline rocks or sandstone. At the type location the average annual precipitation is 18 inches. The mean annual temperature is 39 to 44 degrees F., and the average summer temperature is 60 degrees F. the frost-free season mean annual temperature is 105 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dollard, Jerry, and Redthayne soils. Dollard and Jerry soils lack a mollic epipedon and have a fine, montmorillonitic particle-size control section. Redthayne soils have a mollic epipedon and a cambic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium or slow runoff; moderate permeability.
USE AND VEGETATION: These soils are used principally for grazing wildlife habitat. Principal native vegetation is servicebery, big sagebrush, bluebunch wheatgrass, Junegrass, mountainmahogany, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Mountain areas of central and northwestern Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Gunnison County, Colorado, 1975.
REMARKS: Last updated by the state 7/79.