LOCATION BRIGGSRANCH             MT

Established Series
REV.KTS-RJS
03/2012

BRIGGSRANCH SERIES

The Briggsranch series consists of very shallow, somewhat excessively drained soils that formed in colluvium and residuum derived from conglomerate, quartzite, limestone and dolomite. These soils occur on escarpments, mountain slopes and canyons. Slopes are 15 to 70 percent. Mean annual precipitation is about 405 mm, and the mean annual air temperature is about 3 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, mixed Lithic Cryorthents

TYPICAL PEDON: Briggsranch gravelly loamy sand, on a 60 percent slope in rangeland at an elevation of 2,230 meters (Colors are for dry soil unless otherwise noted).

A--0 to 4 cm; brown (10YR 5/3) gravelly loamy sand, dark brown (10YR 3/3) moist; single grain; loose, nonsticky and nonplastic; few coarse, medium, fine and very fine roots; many fine and very fine irregular interstitial pores; 30 percent gravel and a trace of cobbles; violently effervescent; disseminated calcium carbonate; moderately alkaline (pH 8.2); clear smooth boundary. (3 to 8 cm thick)

C1--4 to 10 cm; pale brown (10YR 6/3) extremely gravelly loamy sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; many coarse, medium, fine and very fine roots; many fine and very fine irregular interstitial pores; 70 percent gravel and a trace of cobbles; violently effervescent; disseminated calcium carbonate; moderately alkaline (pH 8.2); clear wavy boundary.

C2--10 to 22 cm; pale brown (10YR 6/3) extremely gravelly loamy sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; many coarse, medium, fine and very fine roots; many fine and very fine irregular interstitial pores; 80 percent gravel and a trace of cobbles; violently effervescent; disseminated calcium carbonate; moderately alkaline (pH 8.2); abrupt wavy boundary. (combined thickness of C horizons - 10 to 20 cm thick)

R--22 to 152 cm; indurated calcareous conglomerate bedrock.

TYPE LOCATION: Beaverhead County, Montana; located about 2000 feet north and 600 feet west of the SE corner of sec. 5, T. 12 S., R 8 W. Rock Island Ranch topographic quadrangle. UTM 12T, 373774e, 4963916n. NAD 83

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 1 to 4 degrees C.
Depth to lithic contact - 10 to 25 cm

A horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 3 to 5 moist
Chroma: 2 or 3; dry or moist
Textures: loamy sand or sandy loam
Clay content: 1 to 10 percent
Rock fragments: 15 to 50 percent--15 to 50 percent gravel, 0 to 20 percent cobbles
Calcium carbonate equivalent: 15 to 35 percent
Reaction: pH 7.9 to 8.4

C horizons
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: loamy sand or sand
Clay content: 1 to 10 percent
Rock Fragments: 35 to 80 percent--35 to 80 percent gravel, 0 to 25 percent cobbles
Calcium carbonate equivalent: 15 to 35 percent
Reaction: pH 7.9 to 8.4

COMPETING SERIES:
GOLDFLINT (MT) - has lithic contact at depths greater than 25 cm
GRANYLITH (CA) - has lithic contact at depths greater than 25 cm
RODELL (NV) - has lithic contact at depths greater than 25 cm
ZONITE (MT) - has coarse grained igneous rock fragments

GEOGRAPHIC SETTING:
Landform - escarpments, mountain slopes and canyons
Elevation - 1,850 to 2,440 meters
Slope - 15 to 70 percent
Parent material - colluvium and residuum derived from conglomerate, quartzite, limestone and dolomite
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 380 to 610 mm
Mean annual air temperature - 1 to 4 degrees C.
Frost-free period - 50 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; rapid permeability over nearly impermeable bedrock.

USE AND VEGETATION: Briggsranch soils are used mainly for rangeland and wildlife habitat. Potential native vegetation is mainly curlleaf mountain mahogany, grey horsebrush, bluebunch wheatgrass, kingspike fescue, needleandthread, indian ricegrass, prickly pear cactus and miscellaneous forbs and half shrubs.

DISTRIBUTION AND EXTENT: Briggsranch soils are of small extent in southwestern Montana. MLRA - 43B.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.

SERIES ESTABLISHED: Horse Prairie-South Valley Area - Part of Beaverhead County, Montana, 2011; proposed in Beaverhead County, Montana, 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from the soil surface to 4 cm (A horizon)
Lithic contact - at a depth of 22 cm (R horizon)
Particle-size control section - from 0 to 22 cm (A and C horizons).

Briggsranch soils have a cryic temperature regime and an ustic moisture regime.

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National Cooperative Soil Survey
U.S.A.