LOCATION MINESTOPE MTEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, shallow Ustic Haplocryolls
TYPICAL PEDON: Minestope gravelly coarse sandy loam, in grassland (colors are for dry soil unless otherwise noted).
A--0 to 7 inches; brown (10YR 4/3) gravelly coarse sandy loam, dark brown (10YR 3/3) moist; weak medium granular structure; soft, very friable, slightly sticky and non-plastic; common very fine, fine, and medium roots; 15 percent fine subangular pea gravel; slightly acid (pH 6.2), clear smooth boundary. (3 to 8 inches thick)
Bw--7 to 13 inches; brown (10YR 5/3) gravelly coarse sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and non-plastic; common very fine and few fine and medium roots; 30 percent fine subangular pea gravel; neutral (pH 6.6); clear wavy boundary. (4 to 7 inches thick)
BC--13 to 18 inches; light gray (10YR 7/2) very gravelly loamy coarse sand, grayish brown (10YR 5/2) moist; single grain; loose, non-sticky and non-plastic; few very fine roots; 45 percent fine subangular pea gravel; neutral (pH 6.6); clear wavy boundary. (4 to 12 inches thick)
Cr--18 to 23 inches; soft weathered granite bedrock.
R--23 inches; hard granite bedrock.
TYPE LOCATION: Silver Bow County, Montana; 1,950 feet East and 1,850 feet North of the SW corner of sec. 14, T. 2 N., R. 8 W. Butte South topographic quadrangle, UTM zone 12T, 0378918E, 5086306N, NAD 27
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 36 to 42 degrees F., Cryic temperature regime.
Soil moisture control section - 12 inches to the Cr horizon or at the paralithic contact if the Cr occurs within 10 to 12 inches of the surface; dry in some or all parts for 90 or more cumulative days in normal years; not dry in all parts for more than half the cumulative days when soil temperature at a depth of 20 inches is at or above 41 degrees F. Ustic moisture regime
Thickness of mollic epipedon - 7 to 10 inches
Depth to paralithic contact - 10 to 20 inches
Depth to hard granite bedrock - 20 to 40 inches
These soils contain a high proportion of medium, coarse and very coarse angular sand in the sand fraction due to granite or granite-like parent materials.
A Horizon - Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3
Texture: coarse sandy loam, sandy loam, or loamy coarse sand
Clay content: 5 to 16 percent
Rock fragments: 5 to 40 percent-0 to 5 percent cobbles and stones, 5 to 35 percent mainly fine gravel
Reaction: pH 5.6 to 6.8
Bw Horizon - Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3
Texture: coarse sandy loam or sandy loam
Clay content: 8 to 16 percent
Rock fragments: 15 to 40 percent-0 to 5 percent cobbles and stones, 15 to 35 percent mainly fine gravel
Reaction: pH 6.2 to 7.4
BC Horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: loamy sand, loamy coarse sand or coarse sand
Clay content: 2 to 8 percent
Rock fragments: 35 to 60 percent-0 to 10 percent cobbles and stones, 35 to 55 percent mainly fine gravel
Reaction: pH 6.4 to 7.6
COMPETING SERIES: This is the Piloni series. Piloni soils lack a cambic horizon and have greater than 35 percent rock fragments throughout the soil profile.
GEOGRAPHIC SETTING:
Landform- hillslopes, ridges, mountain flanks and bedrock floored pediments
Elevation - 5,180 to 7,610 feet
Slope - 2 to 60 percent
Parent material - residuum from quartz monzonite, granite or other coarse grained igneous or metamorphic rocks
Climate - long cold winters; cool, moist springs; short, dry summers
Mean annual precipitation - 15 to 19 inches
Mean annual air temperature - 34 to 40 degrees F.
Frost-free period - 30 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Wissikihon, Beeftrail, and Zonite series. Wissikihon soils are 40 to 60 deep to bedrock and occur on footslopes, swales and headslope positions. Beeftrail soils are 20 to 40 inches deep over bedrock and occur on similar but slightly more depositional slope positions. Zonite soils are very shallow to bedrock. They occur on convex or otherwise erosional landscape positions and have distinctly limited vegetative cover.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; rapid permeability.
USE AND VEGETATION: Minestope soils are primarily used for rangeland, watershed and wildlife habitat. The native vegetation is mainly Idaho fescue, bluebunch wheatgrass, rubber rabbitbrush, silvery lupine, fringed sagewort, buckwheat and Hoods phlox.
DISTRIBUTION AND EXTENT: Minestope soils are of limited extent in foothills and mountains of southwestern Montana. MLRA 43.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Silver Bow County, Montana, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 7 inches (A horizon); a cambic horizon from 7 to 13 inches (Bw horizon); a paralithic contact at 18 inches (Cr horizon) and a lithic contact at 23 inches (R horizon); a particle-size control section from 10 to 18 inches inches (Bw, BC horizons). Minestope soils have a cryic temperature regime and an ustic soil moisture regime. Gravel throughout the profile are primarily fine pea gravel less than 7 mm in diameter.