LOCATION GOLDFLINT MTEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed Lithic Cryorthents
TYPICAL PEDON: Goldflint loamy coarse sand, in forest (colors are for dry soil unless otherwise noted).
Oi--0 to 1 inch; litter layer of largely undecomposed conifer needles and twigs. (0 to 2 inches thick)
A--1 to 3 inches; brown (10YR 4/3) loamy coarse sand, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, non-sticky and non-plastic; common very fine, fine and medium roots and few coarse and very coarse roots; 10 percent fine subangular gravel; slightly acid (pH 6.4); clear smooth boundary. (1 to 4 inches thick)
Bw--3 to 11 inches; yellowish brown (10YR 5/4) gravelly loamy coarse sand, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; slightly hard, very friable, non-sticky and non-plastic; common very fine, fine, medium, coarse and very coarse roots; 25 percent fine subangular gravel and 2 percent subrounded cobbles; slightly acid (pH 6.4); clear smooth boundary. (0 to 9 inches thick)
BC--11 to 18 inches; variegated colors, mainly yellowish brown (10YR 5/4) and brownish yellow (10YR 6/6) very gravelly coarse sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, non-sticky and non-plastic; common very fine, fine and medium roots and few coarse and very coarse roots; many very fine and fine and common medium interstitial pores; 40 percent fine subangular gravel and 2 percent subrounded cobbles neutral (pH 6.8); abrupt wavy boundary. (6 to 14 inches thick)
R--18 inches; hard granite bedrock.
TYPE LOCATION: Silver Bow County, Montana; 400 feet north and 1400 feet west of the SE corner of sec. 2, T. 4 N., R. 9 W. Ramsey topographic quadrangle, UTM zone 12T, 0370337E, 5108643N, NAD 27.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature 34 to 42 degrees F., Cryic temperature regime.
Soil moisture control section 12 inches to bedrock or at the bedrock contact if shallower than 12 inches, 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 the bedrock contact is at or above 41 degrees F. Ustic moisture regime
Depth to lithic contact 10 to 20 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.
Some profiles have a thin Cr horizon above the lithic contact.
The surface, when mixed to a depth of 7 inches does not meet the color requirements for a mollic epipedon.
A Horizon Hue: 10YR or 7.5YR
Value: 4, 5, or 6 dry; 2, 3, or 4 moist
Chroma: 2, 3, or 4
Texture: coarse sandy loam, loamy coarse sand, sandy loam or coarse sand
Clay content: 2 to 12 percent
Rock fragments: 10 to 70 percent--0 to 40 percent cobbles, stones and boulders, 10 to 45 percent, mainly fine, gravel
Reaction: pH 5.4 to 6.8
Bw Horizon Value: 5 or 6 dry; 3, 4 or 5 moist
Chroma: 2, 3, or 4
Texture: loamy coarse sand or coarse sand
Clay content: 2 to 12 percent
Rock fragments: 20 to 65 percent--0 to 20 percent cobbles, stones and boulders, 20 to 45 percent, mainly fine, gravel
Reaction: pH 5.6 to 7.2
Note: This horizon may be lacking in some profiles.
BC Horizon Value: 5, 6, or 7 dry; 5 or 4 moist
Chroma: 2, 3, 4, or 6
Texture: coarse sand, loamy coarse sand or loamy sand
Clay content: 0 to 6 percent
Rock fragments: 35 to 75 percent--0 to 15 percent cobbles, stones and boulders, 35 to 60 percent, mainly fine, gravel
Reaction: pH 5.4 to 7.2
COMPETING SERIES: These are the Granylith, Rodell and Zonite series. Granylith soils have a xeric moisture regime and have a 3 to 6 inch saturated zone just above the lithic contact for more than 20 consecutive days during spring and early summer. Rodell soils have a xeric moisture regime that borders on aridic. Zonite soils are very shallow.
GEOGRAPHIC SETTING:
Landform- hillslopes, mountain flanks and ridges
Elevation - 5,250 to 8,250 feet
Slope - 4 to 80 percent
Parent material residuum from granite, quartz monzonite or other coarse grained igneous or metamorphic rocks
Climate long cold winters; moist, cool springs; short, dry summers
Mean annual precipitation 15 to 24 inches
Mean annual air temperature 32 to 40 degrees F.
Frost-free period - 20 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Stecum, Zonite, and Basincreekseries. Stecum soils are 20 to 40 inches deep over bedrock and are on similar but somewhat less erosional slope positions. Zonite soils are very shallow. Zonite soils tend to occur on more strongly convex nose, ridge or shoulder slopes. Basincreek soils are deeper than 40 inches to bedrock and have thin lamellae of accumulated clay in one or more E and Bt horizons. Basincreek soils occur in more depositional footslope, swale, and headslope positions.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; rapid permeability over nearly impermeable bedrock.
USE AND VEGETATION: Goldflint soils are primarily used for wildlife habitat, watersheds and limited timber production. The native vegetation is mainly Douglas-fir and/or lodgepole pine with a sparse understory of Idaho fescue, elk sedge, common juniper, Oregon grape, bearberry and pinegrass. Grouse whortleberry and pinegrass are prevalent on moister, high elevation sites.
DISTRIBUTION AND EXTENT: Goldflint soils are of moderate extent in granitic 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: an ochric epipedon from the soil surface to 7 inches (Oi, A, and part of the Bw horizons); a lithic contact at 18 inches (R horizon); a particle-size control section from 10 to 18 inches (part of the Bw and the BC horizons). Goldflint 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.