LOCATION FINGERROCK COTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Argicryolls
TYPICAL PEDON: Fingerrock cobbly loam, 4 percent slope in rangeland at an elevation of 8,400 feet. (Colors are for dry soil unless otherwise noted.) When described on October 10, 1994 the soil was dry from 0 to 80 inches.
A1--0 to 4 inches; dark brown (10YR 3/3) cobbly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots; few fine tubular pores; 10 percent gravel, 10 percent cobbles, 2 percent stones; neutral (pH 6.8); clear smooth boundary.
A2--4 to 12 inches; very dark grayish brown (10YR 3/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; soft, friable, moderately sticky and slightly plastic; common very fine, fine and medium roots; few fine tubular pores; 20 percent gravel, 20 percent cobbles, 5 percent stones; neutral (pH 6.6); clear wavy boundary. (The combined thickness of the A horizon is 8 to 13 inches thick)
Bt--12 to 23 inches; dark yellowish brown (10YR 4/4) very cobbly sandy clay loam, dark yellowish brown (10YR 3/4) moist; moderate fine subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few fine and medium roots; few fine tubular pores; few faint clay films on faces of peds; 20 percent gravel, 25 percent cobbles, 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (8 to 32 inches thick)
BC--23 to 32 inches; dark yellowish brown (10YR 4/4) extremely cobbly sandy loam, dark yellowish brown (10YR 3/4)moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few fine tubular pores; 25 percent gravel, 30 percent cobbles, 10 percent stones; neutral (pH6.6); gradual wavy boundary. (0 to 20 inches thick)
C--32 to 80 inches; dark yellowish brown (10YR 4/4) extremely cobbly loamy sand, dark yellowish brown (10YR 3/4) moist; single grain; loose, nonsticky and nonplastic; very few very fine roots; 30 percent gravel, 30 percent cobbles, 10 percent stones; neutral (pH 6.8); gradual wavy boundary.
TYPE LOCATION: Routt County, Colorado; about 1.5 miles southwest of Yampa, Colorado; located about 200 feet east and 1,100 feet north of the southwest corner of sec. 21, T. 2 N., R. 85 W.; Trapper USGS quad; lat. 40 degrees 7 minutes 26 seconds N. and long. 106 degrees 56 minutes 28 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic
Mean annual soil temperature: 38 to 42 degrees F.
Mean summer soil temperature: 52 to 58 degrees F.
Depth to argillic horizon: 8 to 13 inches (20 to 33 centimeters)
Thickness of argillic horizon: 8 to 20 inches
Thickness of mollic epipedon: 8 to 13 inches
Depth to sandy-skeletal horizon: 24 to 40 inches
Particle-size control section (weighted average):
Clay content: 22 to 35 percent
Rock fragment content: 40 to 75 percent
A horizon(s):
Hue: 7.5YR or 10YR
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: gravelly loam, cobbly loam, very cobbly loam
Clay content: 10 to 25 percent
Fragment content: 5 to 25 percent mixed gravel
0 to 25 percent mixed cobbles
0 to 5 percent mixed stones
Organic matter content: 1.0 to 3.0 percent
Bt horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 3 or 4 dry or moist
Texture: very cobbly sandy clay loam, very gravelly sandy clay loam, extremely cobbly sandy clay loam, extremely gravelly sandy clay loam
Clay content: 22 to 35 percent
Fragment content: 20 to 50 percent mixed gravel
5 to 30 percent mixed cobbles
0 to 5 percent mixed stones
Organic matter content: 0.5 to 1.0 percent
BC horizon (not present in some pedons):
Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 3 or 4 dry or moist
Texture: extremely cobbly sandy loam, extremely gravelly sandy loam
Clay content: 8 to 17 percent
Fragment content: 25 to 45 percent mixed gravel
25 to 40 percent mixed cobbles
0 to 10 percent mixed stones
C horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 3 to 5 moist
Chroma: 3 or 4 dry or moist
Texture: extremely cobbly loamy sand, extremely cobbly coarse sand, extremely cobbly sand, extremely cobbly loamy coarse sand, extremely gravelly loamy coarse sand
Clay content: 3 to 8 percent
Fragment content: 25 to 65 percent mixed gravel
25 to 40 percent mixed cobbles
0 to 10 percent mixed stones
COMPETING SERIES: Current competitors are the Blaine, Bowen, Fornor, Fourmile, Geertsen, Hodden, Hoodle, Lagarita, Libeg, Maciver, Nathale, Nathrop, Norriston, Parkview, Quander, Ratiopeak, Spanpeak, Teeler, and Woodhall series.
Blaine, Bowen, Nathale, Nathrop, Parkview, and Woodhall soils have bedrock at depths of less than 40 inches.
Fornor, Hodden, Lagarita, Maciver, Ratiopeak, Thiel and Teeler soils have secondary calcium carbonates.
Fourmile soils have rock fragments principally of granite lithology.
Norriston soils are less than 20 inches to a sandy-skeletal horizon.
Hoodle and Quander soils lack sandy-skeletal sub-horizons.
Libeg soils have greater than 10 percent clay in the BC or C horizon.
GEOGRAPHIC SETTING:
Parent material: alluvium derived from mixed sources
Landform: stream terraces, strath terraces, and mesas
Slopes: 1 to 10 percent
Elevation: 8,100 to 9,000 feet
Mean annual temperature: 37 to 41 degrees F
Mean annual precipitation: 18 to 25 inches
Precipitation pattern: Precipitation is relatively evenly distributed throughout the year
Frost-free period: 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Tanella and Lintim series. The Tanella soils are moderately well drained and are on elevated floodplains and swales. The Lintim soils have mollic horizons thicker than 15 inches and are on hills.
DRAINAGE AND PERMEABILITY: well drained, low or medium runoff, moderate over rapid permeability.
USE AND VEGETATION: The major use is livestock grazing, irrigated hay, and wildlife habitat. The native plant community is Wyoming sagebrush, rabbitbrush, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Northwest Colorado; LRR E, MLRA 48A; small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Routt County, Colorado, Routt County soil survey area, 2004. The name Fingerrock comes from a nearby geological landmark.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 12 to 23 inches. (Bt horizon)
Mollic epipedon: The zone from 0 to 12 inches. (A1 and A2 horizons)
Argillic horizon: The zone from 12 to 23 inches. (Bt horizon)
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomic Version: Eighth Edition, 1998