LOCATION SHEEK COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Sheek very stony sandy loam, on a southeast facing, 50 percent slope in forest. (Colors are for dry soil unless otherwise noted.)
Oe--0 to 1 inch; moderately decomposed leaves, twigs and needles; abrupt smooth boundary. (0 to 3 inches thick)
A--1 to 5 inches; brown (10YR 5/3) very stony sandy loam, dark brown (10YR 3/3) moist; moderate fine granular structure; hard, friable, slightly sticky and nonplastic; 10 percent gravel, 15 percent cobbles, and 15 percent stones; neutral (pH 6.9); clear wavy boundary. (3 to 7 inches thick)
Bt1--5 to 11 inches; brown (7.5YR 5/4) very stony clay loam, brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; very few faint clay films on faces of peds; 15 percent gravel, 15 percent cobbles, and 20 percent stones; neutral (pH 6.8); gradual wavy boundary. (4 to 25 inches thick)
Bt2--11 to 17 inches; brown (7.5YR 5/4) very stony clay loam, brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few faint clay films on the faces of peds; 15 percent gravel, 15 percent cobbles, and 20 percent stones; neutral (pH 7.0); gradual wavy boundary. (0 to 10 inches thick)
Bt3--17 to 27 inches; brown (7.5YR 5/4) very stony clay loam, brown (7.5YR 4/4) moist; strong coarse subangular blocky structure parting to strong medium angular blocky; very hard, very firm, moderately sticky and moderately plastic; common distinct clay films on faces of peds and in pores; 25 percent gravel, 10 percent cobbles, and 20 percent stones; slightly acid (pH 6.5); gradual wavy boundary. (0 to 15 inches thick)
Bt4--27 to 43 inches; 70 percent brown (7.5YR 5/4) very stony clay loam, brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few faint clay films on faces of peds; 25 percent gravel, 10 percent cobbles, 20 percent stones; neutral (pH 6.6); gradual wavy boundary. (0 to 20 inches thick)
BC--43 to 60 inches; brown (7.5YR 5/4) very stony clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; very hard, very firm, moderately sticky and moderately plastic; 30 percent gravel, 5 percent cobbles, and 20 percent stones; slightly alkaline (pH 7.4).
TYPE LOCATION: Montezuma County, Colorado; about 3 1/2 miles east of the community of Mancos; located about 200 feet west and 900 feet north of the southeast corner of sec. 36, T. 36 N., R. 13 W.; Thompson Park, Colorado USGS quad; lat. 37 degrees 19 minutes 48 seconds N. and long. 108 degrees 13 minutes 42 seconds W., NAD 27
RANGE IN CHARACTERISTICS: (depths given are measured from the mineral soil surface)
Surface rock fragments: 20 to 60 percent sandstone gravel, cobble, stones
Soil moisture regime: ustic; (typic ustic subclass)
Mean annual soil temperature: 43 to 47 degrees F
Mean summer soil temperature: 50 to 64 degrees F
Lithology of rock fragments: sandstone
Particle-size control section:
Clay content: 18 to 35 percent
Rock fragment content: 35 to 70 percent
A horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 to 4 dry or moist
Texture: sandy loam, loam, or clay loam
Rock fragments: 35 to 45 percent gravel, 20 to 60 percent cobbles, 0 to 10 percent stones
Reaction: slightly acid to slightly alkaline
E horizon: some pedons may have an E horizon
Bt horizon:
Hue: 7.5YR to 2.5Y
Value: 4 to 7 dry, 3 or 6 moist
Chroma: 4 to 6 dry or moist
Texture: loam, clay loam, or sandy clay loam
Rock fragments: 35 to 70 percent gravel, cobble, and stone
Reaction: slightly acid to slightly alkaline
BC or C horizon: if present
Hue: 7.5YR to 2.5Y
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 4 to 6 dry or moist
Rock fragments: 35 to 80 percent gravel, cobble, and stones
Reaction: slightly acid to slightly alkaline
COMPETING SERIES: These are the Abreu, Colomex, Laventana, Littlewater, Macmeal, Mocmont, Namon, Skyview, Sonsela, Tecolote, Towaoc, Trapps, Vision, Wahatoya, Xankey, Ymark, Yourame, and Yreka series.
Abreu: have a lithic contact at 20 to 40 inches.
Colomex: formed in material derived from metamorphic and igneous rocks.
Laventana: formed in material derived from andesite and granite.
Littlewater: have rock fragments of dioriteMacmeal soils formed in igneous and metamorphic rocks and have accumulations of secondary calcium carbonate.
Mocmont soils have a glossic horizon.
Namon: have a lithic contact at 40 to 60 inches.
Skyview: have a lithic contact at 23 to 40 inches.
Sonsela: formed in colluvium derived from basalt and tuff-breccia.
Tecolote: have albic horizons.
Towaoc: have rock fragments of diorite.
Trapps soils have an albic horizon.
Vision soils have soil moisture control sections that are affected by peak precipitation periods during the spring and early summer.
Wahatoya: have a lithic contact at 20 to 40 inches.
Xankey: have less than 25 percent rock fragments in the substratum.
Ymark: have a lithic contact at 43 to 60 inches.
Yourame soils formed in till, have E/Bt horizons, and have soil moisture control sections that are affected by peak precipitation periods during the spring and early summer.
Yreka: have a moisture pattern with peak periods of precipitation in
May and June.
GEOGRAPHIC SETTING:
Parent material: gravelly, cobbly, and stony, colluvium and slope alluvium derived from sandstone and shale
Landform: canyons, hills, mesas, and mountain slopes.
Slopes: 3 to 80 percent
Elevation: 7,100 to 8,500 feet
Mean annual temperature: 40 to 47 degrees F
Mean annual precipitation: 15 to 22 inches
Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly dryer.
Frost-free period: 75 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Archuleta and Hesperus soils. Archuleta soils are shallow and nonskeletal and are on similar landscapes. Hesperus soils are nonskeletal and pachic and are in drainageways and hills.
DRAINAGE AND PERMEABILITY: well drained, medium to very high runoff, moderate or moderately slow permeability
USE AND VEGETATION: Most areas are used for wood products, wildlife habitat and recreation. A few areas are used for grazing. Native vegetation is ponderosa pine, Douglas-fir, Gambel's oak, mountain muhly, Arizona fescue, and prairie junegrass.
DISTRIBUTION AND EXTENT: Southwest Colorado. LRR E, MLRA 36. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Montezuma County, Colorado, 1997; Cortez Soil Survey Area.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 1 to 5 inches. (A horizon)
Argillic horizon: from 5 to 43 inches. (Bt1, Bt2, Bt3, and Bt4 horizons)
Particle-size control section: The zone from 5 to 25 inches. (Bt1, Bt2, and Bt3 horizons)
The activity class is assumed based on the general trend of other soils in the area.
Taxonomy version: 9th Edition 2003