LOCATION MARBLECREEK IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Dystrudepts
TYPICAL PEDON: Marblecreek gravelly ashy silt loam, forest; on southeast-facing slope of 65 percent at 4,000 feet elevation. When described on September 26, 1982, the soil was moist throughout. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 0.5 inches; slightly decomposed needles, leaves, and twigs.
Oe--0.5 to 1.5 inches; decomposed organic matter mixed with Mt. St. Helens volcanic ash. (O horizons 0 to 1.5 inches thick)
A--1.5 to 5 inches; brown (10YR 5/3) gravelly ashy silt loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure parting to weak fine and medium granular; soft, very friable, nonsticky and slightly plastic; many very fine, fine, and medium roots; many very fine tubular pores; 25 percent gravel; neutral (pH 7.0); clear wavy boundary. (2 to 4 inches thick)
Bw1--5 to 13 inches; light yellowish brown (10YR 6/4) gravelly ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine, fine, medium and few coarse roots; many very fine and fine tubular pores; 25 percent gravel, 5 percent cobbles; neutral (pH 6.8); abrupt wavy boundary. (5 to 9 inches thick)
2Bw2--13 to 27 inches; very pale brown (10YR 7/4) very gravelly sandy loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; many very fine, fine, and few medium and coarse roots; many very fine and fine tubular and irregular pores; few faint clay films lining pores; 40 percent gravel, 10 percent cobbles; slightly acid (pH 6.2); gradual wavy boundary. (6 to 32 inches thick)
2BC--27 to 46 inches; pink (7.5YR 7/4) extremely gravelly sandy loam, brown (7.5YR 5/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine irregular pores; many very fine mica flakes; 50 percent gravel, 20 percent cobbles; slightly acid (pH 6.5); gradual wavy boundary. (0 to 27 inches thick)
2C--46 to 62 inches; pink (7.5YR 7/4) extremely cobbly loamy sand, brown (7.5YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine irregular pores; many very fine mica flakes; 45 percent gravel, 45 percent cobbles; slightly acid (pH 6.5).
TYPE LOCATION: Shoshone County, Idaho; about 2 miles southeast of the community of Herrick, about 1,750 feet west and 2,000 feet north of the southeast corner of sec. 16, T. 45. N., R. 3 E. Latitude -47 degrees, 14 minutes, 39 seconds North; Longitude - 116 degrees, 04 minutes, 50 seconds West; USGS Marble Mountain quadrangle.
RANGE IN CHARACTERISTICS:
Soil moisture - usually dry for 30 to 40 consecutive days August and September, moist mid-September through July (Udic moisture regime)
Average annual soil temperature - 43 to 46 degrees F
Average summer soil temperature - 49 to 53 degrees F with an O horizon (frigid temperature regime)
Depth to bedrock - greater than 60 inches
Solum thickness - 15 to 50 inches
Volcanic ash mantle - 9 to 13 inches thick
Volcanic glass content - 30 to 65 percent
Acid-oxalate extractable Al + 1/2 Fe - 1.0 to 3.0 percent
A horizon
Hue - 10YR to 7.5YR dry or moist
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 to 4 dry or moist
Texture - GR-Ashy-SIL, Ashy-SIL, Ashy-L
Clay content - 3 to 10 percent
Rock fragments - 0 to 25 percent gravel
Bulk density - 0.65 to 0.95 g/cc
Reaction - moderately acid to neutral
Bw horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 moist
Texture - GR-Ashy-SIL, GR-Ashy-L, Ashy-SIL, Ashy-L
Clay content - 3 to 12 percent
Rock fragments - 0 to 30 percent gravel, 0 to 15 percent cobbles, 0 to 30 percent total fragments
Bulk density - 0.65 to 0.95 g/cc
Reaction - moderately acid to neutral
2Bw horizon
Hue - 10YR or 7.5YR dry or moist
Value - 5 to 7 dry, 3 to 6 moist
Chroma - 3 or 4 dry or moist
Texture - GRV-SL, GRV-L, GRV-FSL, CBV-SL, CBV-L, CBV-FSL, GR-L, GR-SL
Clay content - 3 to 17 percent
Rock fragments - 25 to 55 percent gravel, 0 to 25 percent cobbles, 30 to 50 percent total fragments
Reaction - moderately acid or slightly acid
2C and 2BC horizons
Hue - 10YR or 7.5YR dry or moist
Value - 6 to 8 dry, 5 to 7 moist
Chroma - 2 to 4 dry, 2 to 6 moist
Texture - GRX-SL, GRX-LS, CBX-SL, CBX-LS, FLX-SL, FLX-LS, GRV-FSL
Clay content - 0 to 12 percent
Coarse fragments - 35 to 90 percent gravel, 0 to 10 percent cobbles, 35 to 90 percent total fragments
Reaction - moderately acid or slightly acid
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Marblecreek soils are on east, west, and south aspects of mountains. Slopes range from 15 to 80 percent. These soils formed in material weathered from schist and quartzite bedrock, with a mantle of volcanic ash and loess. Elevations range from 2,000 to 5,200 feet. The average annual air temperature ranges from 41 to 46 degrees F, and average annual precipitation is 30 to 50 inches. The average frost-free period is from 50 to 110 days (9 in 10 years to 1 in 10 years, respectively).
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackprince (T), Bouldercreek (T), Jacot, and Nakarna soils. Blackprince soils are on south-facing foothills and have soft bedrock at depths of 20 to 40 inches. Bouldercreek soils are on north-facing mountain slopes and are ashy over loamy-skeletal. Jacot soils are on north-facing foothills and are ashy over loamy. Nakarna soils are on north-facing mountain slopes and are ashy over loamy.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability in the solum, and moderately rapid to rapid permeability in the substratum.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, recreation, wildlife habitat, and watershed. Potential natural vegetation is mainly grand fir, western larch, Douglas-fir, western white pine, and ponderosa pine, with an understory of queencup beadlily, longtube twinflower, myrtle pachystima, goldthread, common snowberry, piper anemone, Columbia brome, American trailplant, and sedge.
DISTRIBUTION AND EXTENT: Northern Idaho. This soil is moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Shoshone County, Idaho, 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 1.5 to 5 inches (A horizon)
Cambic horizon - the zone from 5 to 27 inches (Bw1 and 2Bw2 horizon)
Volcanic ash mantle - the zone from 1.5 to 13 inches (A and Bw1 horizons)
Particle-size control section - the zone from 10 to 40 inches (part of the Bw1, 2Bw2 and part of the 2BC horizon)