LOCATION COPPERBASIN ID+MTEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed Aquic Haplocryolls
TYPICAL PEDON: Copperbasin very gravelly fine sandy loam--on a 3 percent slightly undulating, northeast aspect at 6,250 feet elevation in woodland. (Colors are for dry soil unless otherwise noted. When described on August 1, 1985, the soil was moist throughout.)
A--0 to 5 inches; grayish brown (10YR 5/2) very gravelly fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium and thick platy structure; slightly hard, friable, slightly sticky and nonplastic; many very fine and fine, common medium and coarse roots; common very fine and fine tubular and interstitial pores; 35 percent gravel, 10 percent cobbles; slightly alkaline (pH 7.5); clear smooth boundary. (3 to 10 inches thick)
AC--5 to 10 inches; grayish brown (10YR 5/2) extremely gravelly loamy fine sand, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; common fine and medium irregular pores; 65 percent gravel, 20 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (0 to 9 inches thick)
C1--10 to 25 inches; multicolored extremely gravelly loamy sand; common fine and medium prominent yellowish brown (10YR 5/6 and 5/8) redox concentrations on rock fragments; single grain; loose; common very fine, fine, medium and coarse roots; many medium and coarse irregular pores; 50 percent gravel, 30 percent cobbles, 5 percent stones; slightly alkaline (pH 7.4); gradual wavy boundary. (8 to 19 inches thick)
C2--25 to 33 inches; multicolored extremely cobbly sand; common fine and medium prominent yellowish brown (10YR 5/6 and 5/8) redox concentrations on rock fragments; single grain; loose; few fine and coarse irregular pores; 30 percent gravel, 40 percent cobbles, 5 percent stones; neutral (pH 7.2); gradual wavy boundary. (5 to 18 inches thick)
C3--33 to 60 inches; multicolored extremely gravelly coarse sand; common fine and medium prominent yellowish brown (10YR 5/6 and 5/8) redox concentrations on rock fragments; single grain; loose; few fine and medium roots; many medium and coarse irregular pores; 45 percent gravel, 30 percent cobbles, 10 percent stones; neutral (pH 7.2).
TYPE LOCATION: Custer County, Idaho; approximately 1.5 miles south of the Highway 93 - Trail Creek Road junction, about 800 feet north and 1,600 feet west of the southeast corner of section 3, T.8N., R.22E. Latitude - 44 degrees, 2 minutes and 50 seconds North; Longitude - 113 degrees, 49 minutes and 48 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 35 to 43 degrees F.
Average summer soil temperature - 49 to 55 degrees F.
Some pedons have an O horizon
Mollic epipedon thickness - 10 to 15 inches
Control section:
Clay - 2 to 10 percent
Rock fragments - 60 to 85 percent
Depth to high water table - 1.5 to 3.5 feet from March through June
A horizon
Value - 3, 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3, dry or moist
Texture - FSL, L
Clay content - 10 to 27 percent
Reaction - pH 6.4 to 7.8
AC horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3, dry or moist
Texture - GRX-LFS, GRV-SL, GRX-LS, GRV-LS, CBX-LS
Clay content - 8 to 15 percent
Rock fragments - 50 to 85 percent
Reaction - pH 6.5 to 7.8
C horizons
Texture - GRX-LS, GRX-LCOS, GRX-COS, CBX-S, CBX-COS, CBX-LS
Clay content - 0 to 10 percent
Rock fragments - 60 to 85 percent
Reaction - pH 6.6 to 7.8
COMPETING SERIES: This is the Cavebear (T) series.
Cavebear soils - have mollic epipedons 16 to 24 inches thick; 35 to 60 percent rock fragments in the particle-size control section; and receive 30 to 45 inches average annual precipitation.
GEOGRAPHIC SETTING: Copperbasin soils are on flood plains and stream terraces. These soils formed in alluvium. Slopes are 0 to 4 percent. Elevations are 4,500 to 7,400 feet. The climate is cold and moist in winter and spring and cool in summer. The average annual precipitation is 10 to 19 inches. Average annual temperature is 34 to 42 degrees F. Frost-free period is 5 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Biglost and Wiskisprings soils. Biglost soils are on flood plains and have mollic epipedons that are 16 to 25 inches thick and strongly contrasting particle-size control sections. Wiskisprings soils are on flood plains and have mollic epipedons that are 16 to 30 inches thick and have fine-loamy particle-size control sections.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Slow runoff. Moderately rapid over very rapid permeability. This soil floods occasionally for brief periods in January through June.
USE AND VEGETATION: Woodland. The natural vegetation is black cottonwood, bluegrass and wheatgrass.
DISTRIBUTION AND EXTENT: East-central Idaho and southwest Montana. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 0 to 10 inches (the A and AC horizons).
Particle-size control section - The zone from 10 to 40 inches (the C1, C2, and part of the C3 horizons).