LOCATION GOLDPARK COEstablished Series
TAXONOMIC CLASS: Fine, smectitic Ustic Haplocryalfs
TYPICAL PEDON: Goldpark clay loam, on an east facing, 15 percent mountain slope, in rangeland at an elevation of 8,720 feet. (colors are for dry soil unless otherwise noted)
A1--0 to 5 inches; light brownish gray (10YR 6/2) clay loam, very dark gray (10YR 3/1) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 10 percent gravel; neutral (pH 7.0); clear smooth boundary.
A2--5 to 12 inches; light brownish gray (10YR 6/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 10 percent gravel; neutral (pH 6.8); clear smooth boundary. (combined thickness of the A horizon is 6 to 20 inches)
Bt1--12 to 23 inches; grayish brown (10YR 5/2) cobbly clay, very dark grayish brown (10YR 3/2) moist; strong coarse and very coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common faint clay films on faces of peds; few faint pressure faces; few cracks, 30 mm to 40 mm long, 1 mm to 4 mm wide when dry; 5 percent gravel, 15 percent cobbles; neutral (pH 7.0); clear smooth boundary.
Bt2--23 to 28 inches; brown (10YR 5/3) gravelly clay, dark brown (10YR 3/3) moist; strong coarse and very coarse subangular blocky structure; hard, firm, sticky and plastic; many distinct clay films on faces of peds; common distinct pressure faces; few cracks, 30 mm to 40 mm long, 1 mm to 4 mm wide when dry; 15 percent gravel; neutral (pH 7.2); clear smooth boundary.
Bt3--28 to 36 inches; pale brown (10YR 6/3) cobbly clay, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; hard, firm, sticky and plastic; many distinct clay films on faces of peds; many prominent pressure faces; few cracks, 30 mm to 40 mm long, 1 mm to 4 mm wide when dry; 10 percent gravel, 15 percent cobbles; neutral (pH 7.0); clear smooth boundary.
Bt4--36 to 45 inches; light yellowish brown (2.5Y 6/3) gravelly clay loam, olive brown (2.5Y 4/3) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and plastic; few faint clay films on faces of peds; 20 percent gravel; slightly effervescent; slightly alkaline (pH 7.4); clear smooth boundary.
Bt5--45 to 66 inches; light yellowish brown (2.5Y 6/4) clay, olive brown (2.5Y 4/4) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and plastic; few faint clay films on faces of peds; 5 percent gravel; slightly effervescent; slightly alkaline (pH 7.6). (combined thickness of the Bt horizons is 20 to 50 inches)
TYPE LOCATION: Saguache County, Colorado; about 6 miles south of Doyleville, Colorado; located about 150 feet north and 1800 feet east of the southwest corner of Section 32, T. 48 N., R. 4 E.; USGS West Baldy topographic quadrangle; latitude 38 degrees, 22 minutes, 14 seconds north and longitude 106 degrees, 33 minutes, 18 seconds west, NAD 1927.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section (smcs) is affected by precipitation that falls evenly throughout the year with the exception of a significant increase in July and August. The smcs is driest during the fall. The smcs is too dry for Udic and is considered to have an Ustic soil moisture regime.
Mean annual soil temperature: 42 to 44 degrees F.
Particle-size control section: 35 to 50 percent clay, 5 to 30 percent rock fragments.
Depth to top of argillic horizon: 6 to 20 inches.
A horizons:
Hue: 10YR or 2.5Y
Value: 6 or 7 dry, 2 or 3 moist
Chroma: 2 or 3 dry, 1 to 3 moist
Reaction: neutral (pH 6.6) to (pH 7.3)
Rock fragments: andesite, rhyolite, breccia, or tuff. 0 to 15 percent total rock fragments; 0 to 15 percent gravel, 0 to 5 percent cobbles.
Bt horizons:
Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 2 to 4 dry or moist
Texture: clay, clay loam, cobbly clay, gravelly clay, cobbly clay loam, gravelly clay loam
Reaction: neutral (pH 6.6) to slightly alkaline (pH 7.8)
Rock fragments: andesite, rhyolite, breccia, or tuff. 5 to 30 percent total rock fragments; 0 to 20 percent gravel, 0 to 20 percent cobbles.
COMPETING SERIES: These are the
Chubbs and
Hatch series
Chubbs: lithic contact with limestone between 20 and 40 inches deep
Hatch: paralithic contact with siltstone between 20 and 40 inches deep
GEOGRAPHIC SETTING:
Parent material: slope alluvium derived from shale with colluvial influence from andesite, rhyolite, breccia, or tuff
Landform: mountain slopes
Slopes: 5 to 25 percent
Elevation: 8,600 to 9,600 feet
Mean annual temperature: 38 to 41 degrees F.
Mean annual precipitation: 16 to 20 inches
Frost-free period: 60 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Quander and Tellura soils. Quander soils are on backslopes and shoulders and have more than 35 percent rock fragments in the particle-size control section. Tellura soils are on toeslopes and have more that 35 percent rock fragments in the particle-size control section.
DRAINAGE AND PERMEABILITY: well drained; very high runoff; slow permeability.
USE AND VEGETATION: This soil is used for rangeland. Native vegetation is currently mountain big sagebrush, western wheatgrass, Arizona fescue, and muttongrass. Potential native vegetation is Arizona fescue, bearded wheatgrass, Letterman needlegrass, and slender wheatgrass. It is in the Mountain Loam Range Site, RS 228.
DISTRIBUTION AND EXTENT: Southwest Colorado in LRR E and MLRA 48A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cochetopa Soil Survey Area, Gunnison National Forest, Saguache County, Colorado, 1999. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon.
Particle-size control section: the zone from 12 to 32 inches. (Bt1, Bt2, Bt3 horizons)
Ochric epipedon: the zone from 0 to 12 inches. (A1, A2 horizons)
Argillic horizon: the zone from 12 to 60 inches. (Bt horizons)
The soil potentially has a xeric soil moisture regime.
Taxonomic version: Eighth Edition, 1998.