LOCATION REMOUNT MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Calcic Argixerolls
TYPICAL PEDON: Remount very gravelly loam, in pasture. (Colors are for dry soil unless otherwise noted)
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) very
gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and nonplastic; common fine, and medium, and few coarse roots; 40 percent pebbles; neutral (pH 6.8); abrupt smooth boundary.
A2--7 to 11 inches; brown (10YR 5/3) very gravelly loam, dark brown (10YR 3/3) moist; weak moderate subangular blocky
structure; soft, very friable, slightly sticky and slightly
plastic; common fine, and medium, and few coarse roots; many fine pores; 55 percent pebbles; neutral (pH 7.2); clear smooth boundary. (combined A horizons 7 to 12 inches thick)
Bt--11 to 15 inches; light yellowish brown (10YR 6/4) extremely gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak moderate subangular blocky structure; soft, friable, sticky and slightly plastic; few fine and medium roots; many fine pores; common distinct clay films on faces of peds and on surface of pebbles; 75 percent pebbles; slighlty alkaline (pH 7.4); clear smooth boundary.
Btk--15 to 25 inches; light yellowish brown (10YR 6/4)
extremely gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak moderate subangular blocky structure; soft, very friable slightly sticky and slightly plastic; few very fine and fine roots; few faint clay films on faces of peds and on surface of pebbles; 85 percent pebbles; strongly effervescent, lime on undersides of pebbles; slightly alkaline (pH 7.8); gradual smooth boundary. (combined Bt horizons 8 to 16 inches thick)
Bk--25 to 60 inches; light yellowish brown (10YR 6/4) extremely gravelly coarse sandy loam, dark yellowish brown (10YR 4/4) moist; loose; loose, nonsticky and nonplastic; few very fine roots; 85 percent pebbles; strongly effervescent, lime mainly on undersides of pebbles; moderately alkaline (pH 8.0).
TYPE LOCATION: Sanders County, Montana; 50 feet east and 1200 feet north of the southwest corner of section 24, T. 20 N., R. 24 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 43 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 7 to 12 inches.
Depth to Btk horizon - 10 to 24 inches.
A horizons - Hue: 10YR or 2.5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3
Clay content: 10 to 18 percent
Rock fragments: 35 to 60 percent; 35 to 55 percent pebbles, 0 to 5 percent cobbles
Reaction: pH 6.6 to 7.8
Bt horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Clay content: 20 to 35 percent
Rock fragments: 60 to 85 percent; 60 to 75 percent pebbles, 0 to 10 percent cobbles
Reaction: pH 7.4 to 7.8
Btk horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Clay content: 20 to 35 percent
Rock fragments: 75 to 90 percent; 75 to 85 percent pebbles, 0 to 5 percent cobbles
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
Bk horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Clay content: 5 to 20 percent
Rock fragments: 75 to 90 percent; 75 to 85 percent pebbles, 0 to 5 percent cobbles
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Amelar (NV) - has less than 60 percent coarse fragments in the Bt horizon.
Broad (UT) - has a lithic contact at 20 to 40 inches.
Custco (ID) - has mean annual air temperature of 37 to 40 degrees F.; does not have a Btk horizon.
Drage (ID) - greater than 24 inches to horizons of secondary carbonate accumulation; does not have a Btk horizon; has less than 60 percent coarse fragments in the Bt horizon.
Scalfar (NV) - has a lithologic discontinuity at 10 to 14 inches; has less than 60 percent coarse fragments in the Bt horizon.
Searla (ID) - has less than 60 percent coarse fragments in the Bk horizon; has a frost free period of 50 to 100 days.
Sheep Creek (UT) - has a lithic contact at 26 to 40 inches.
Small (ID) - has a lithic contact at 20 to 40 inches.
Swampydraw (ID) - has a mean annual soil temperature of 38 to 43 degrees F.; has less than 60 percent coarse fragments in the Bt horizon.
GEOGRAPHIC SETTING:
Landform - giant ripple marks.
Elevation - 2800 to 3000 feet.
Parent material - alluvium.
Slope- 2 to 25 percent.
Climate - long, cold winters; moist springs; warm, dry summers.
Mean annual precipitation - 12 to 16 inches, much of which falls as snow and spring rains.
Mean annual temperature - 41 to 45 degrees F.
Frost-free period - 105 to 125 days.
DRAINAGE AND PERMEABILITY: Excessively drained; moderate over very rapid permeability.
USE AND VEGETATION: These soils are used as range and pasture. The potential native vegetation is bluebunch wheatgrass, prairie junegrass, buckwheat, and fringed sagewort.
DISTRIBUTION AND EXTENT: These soils are of limited extent in northwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sanders County, Montana, 1997.
REMARKS: Soil interpretation record: MT1143. Diagnostic horizons and features recognized in this pedon are: A mollic epipedon from the soil surface to 11 inches (Ap and A2 horizons); an argillic horizon from 11 to 25 inches (Bt and Btk horizons); a layer of lime accumulation from 15 to 60 inches (Btk and Bk horizons); a particle size control section from 11 to 25 inches (Bt and Btk horizons). Remount soils have a frigid temperature regime and a xeric moisture regime.