LOCATION GRAPIT COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, carbonatic, frigid Aridic Calciustolls
TYPICAL PEDON: Grapit gravelly loam in pinyon pine and Utah juniper. (Colors are for dry soil unless otherwise noted.)
The surface is covered by 15 percent gravel and 20 percent cobbles limestone rock fragments.
A--0 to 5 inches; brown (7.5YR 5/2) gravelly loam, dark brown (7.5YR 3/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; common fine roots; 20 percent gravel, 5 percent cobbles; slightly alkaline (pH 7.8); clear smooth boundary. (4 to 16 inches thick)
AB--5 to 14 inches; brown (7.5YR 5/3) very gravelly loam, dark brown (7.5YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable, sticky and plastic; common fine and medium, few coarse roots; 30 percent gravel, 10 percent cobbles; very few fine irregular calcium carbonate threads; strongly effervescent; 28 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 12 inches thick)
Bk1--14 to 30 inches; light brown (7.5YR 6/3) extremely gravelly loam, brown (7.5YR 5/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; common fine and medium roots; common very fine and fine tubular pores; 45 percent gravel, 20 percent cobbles; common fine and medium irregular soft masses of calcium carbonate; violently effervescent; 49 percent calcium carbonate equivalent; moderately alkaline (pH 8.4); gradual wavy boundary. (10 to 40 inches thick)
Bk2--30 to 54 inches; pink (7.5YR 7/3) extremely cobbly loam, light brown (7.5YR 6/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium roots; few very fine tubular pores; 20 percent gravel, 50 percent cobbles; many medium and coarse irregular soft masses of calcium carbonate; violently effervescent; 42 percent calcium carbonate equivalent; strongly alkaline (pH 8.6); gradual wavy boundary. (0 to 35 inches thick)
C--54 to 60 inches; light brown (7.5YR 6/3) very cobbly loam, brown (7.5YR 5/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; few very fine tubular pores; 15 percent gravel, 30 percent cobbles; few fine irregular soft masses of calcium carbonate; strongly effervescent; 21 percent calcium carbonate equivalent; strongly alkaline (pH 8.6).
TYPE LOCATION: Dinosaur National Monument, Moffat County, Colorado; located about 275 feet west and 1,300 feet north of the southeast corner, section 29, T. 6 N., R. 100 W. <EP>Haystack Rock, Colorado USGS quad; Lat. 40 degrees 26 minutes 19 seconds N. and Long. 108 degrees 38 minutes 41 seconds W. NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is dry 60 to 70 percent of the time, cumulative, when the soil temperature at a depth of 20 inches is above 41 degrees F.; Soil moisture regime: Ustic bordering on aridic.
Mean annual soil temperature: 43 to 46 degrees F
Depth to calcic horizon: 7 to 15 inches
Thickness of the mollic epipedon: 7 to 15 inches
Particle-size control section (weighted average):
Clay content: 18 to 27 percent
Rock fragments: 35 to 80 percent
A horizon:
Value: 2 or 3 moist
Chroma: 2 or 3 dry, 1 to 3 moist
Reaction: slightly alkaline or moderately alkaline
Bk horizon:
Value: 5 to 7 dry, 5 or 6 moist
Chroma: 2 to 6
Texture: L or SIL modified by 35 to 80 percent gravel, cobbles, channers, stones, or flagstones
Clay content: 18 to 27 percent
Rock fragments: 35 to 80 percent
Calcium carbonate equivalent: 40 to 50 percent
Reaction: moderately alkaline or strongly alkaline
C horizon: (if present)
Value: 6 or 7 dry, 5 or 6 moist
Chroma: 3 to 6
Texture: SL or L modified by 35 to 70 percent gravel, cobbles, channers, stones, or flagstones
Rock Fragments: 35 to 70 percent
Reaction: moderately alkaline or strongly alkaline
COMPETING SERIES: This is the
Ashlo series.
Ashlo: hue 10YR or yellower
GEOGRAPHIC SETTING:
Parent material: slope alluvium and colluvium derived from limestone
Landform: hills and valleys
Slopes: 12 to 75 percent
Elevation: 6,300 to 8,500 feet
Mean annual temperature: 42 to 45 degrees F
Mean annual precipitation: 12 to 14 inches
Precipitation pattern: precipitation is relatively evenly distributed throughout the year
Frost-free period: 75 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cragnot and Pensore series. Cragnot soils lack a mollic epipedon. Pensore soils have lithic contact less than 20 inches deep.
DRAINAGE AND PERMEABILITY: Well drained, low to high runoff, moderate permeability.
USE AND VEGETATION: These soils are used for rangeland, wildlife habitat, and recreation. Potential vegetation is Pinyon pine, Utah juniper, Wyoming big sagebrush, western wheatgrass, Indian ricegrass, true mountainmahogany, Nevada bluegrass, prairie junegrass, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Northwestern Colorado; LRR D, MLRA 34 and LRR E, MLRA 47; this series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Uintah County, Utah, 1985. The name is coined.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 14 inches. (A1 and AB horizons)
Calcic horizon: The zone from 14 to 54 inches. (Bk1 and Bk2 horizons)
Other features: Carbonatic feature - calcium carbonate equivalent is 40 to 50 percent by weight for the whole soil.
The Grapit series is no longer used in Uintah County, Utah so the type location was moved to Moffat County, Colorado (Dinosaur National Monument) in 1998 and a new typical pedon was used.
Taxonomic Version: Eighth Edition, 1998.
Prior classification was loamy-skeletal, carbonatic, Aridic Calciborolls.