LOCATION CLASOIL MT

Established Series
Rev. DES-TJK-RJS
10/2012

CLASOIL SERIES

The Clasoil series consists of very deep, well drained soils that formed in alluvium or outwash derived from granitic and other coarse grained igneous rocks. These soils are on mountains, hills, fan remnants, alluvial fans, stream terraces and outwash fans. Slopes are 0 to 60 percent. Mean annual precipitation is about 430 mm and mean annual air temperature is about 4.5 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Argiustolls

TYPICAL PEDON: Clasoil gravelly loam, bouldery in rangeland (colors are for dry soil unless otherwise noted).

A1--0 to 13 cm; very dark grayish brown (10YR 3/2) gravelly loam, black (10YR 2/1) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine and medium roots; many very fine and fine interstitial pores; 5 percent cobbles, 10 percent gravel; slightly acid (pH 6.2); clear smooth boundary.

A2--13 to 33 cm; dark grayish brown (10YR 4/2) gravelly loam, very dark gray (10YR 3/1) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; many very fine and few fine and medium roots; many very fine and common fine pores; 5 percent cobbles; 25 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (Combined thickness of A horizons is 10 to 38 cm)

Bt1--33 to 61 cm; light yellowish brown (10YR 6/4) gravelly sandy clay loam, yellowish brown (10YR 5/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, moderately sticky and moderately plastic; common very fine and few fine and medium roots; common very fine and fine pores; common thin clay films on the faces of peds and bridging between sand grains; 5 percent cobbles, 15 percent gravel; neutral (pH 6.7); clear smooth boundary.

Bt2--61 to 86 cm; light yellowish brown (2.5Y 6/4) cobbly sandy clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine and few fine and medium roots; common very fine and few fine pores; common thin clay films on faces of peds and bridging between sand grains; 20 percent cobbles, 10 percent gravel; neutral (pH 6.7); clear smooth boundary. (Combined thickness of Bt horizons is 20 to 61 cm)

BC--86 to 152 cm; light yellowish brown (10YR 6/4) very cobbly loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; 25 percent cobbles, 15 percent gravel; neutral (pH 6.6).

TYPE LOCATION: Jefferson County, Montana; 152 meters north and 305 meters east of the SW corner of sec. 13, T. 9 N., R. 2 W.

RANGE IN CHARACTERISTICS:
Soil temperature - 3.2 to 7.8 degrees C.
Moisture control section - between 10 and 30 cm
Mollic epipedon thickness - 18 to 38 cm
Depth to argillic horizon - 10 to 56 cm

A horizons
Hue: 10YR or 2.5Y; dry or moist
Value: 2 to 4 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Texture: loam or sandy loam
Clay content: 12 to 20 percent
Rock fragments: 0 to 35 percent--0 to 25 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction: pH 5.1 to 7.3

Bt horizons
Hue: 10YR or 2.5Y; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 1 to 4; dry or moist
Texture: sandy clay loam, loam or clay loam
Clay content: 18 to 30 percent
Rock fragments: 5 to 35 percent--5 to 35 percent gravel, 0 to 20 percent cobbles and stones
Reaction: pH 5.6 to 7.3

BC horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 to 6; dry or moist
Texture: sandy loam, loam or coarse sandy loam
Clay content: 12 to 20 percent
Rock fragments: 15 to 40 percent--15 to 35 percent gravel, 0 to 25 percent cobbles and stones
Reaction: pH 6.1 to 7.8

COMPETING SERIES:
Absarook (MT) - has a lithic contact at 50 to 100 cm
Archmesa (CO) - has a lithic contact at 50 to 100 cm
Beartooth (MT) - has calcium carbonate present
Beeno (WY) - has a paralithic contact between depths of 50 to 100 cm
Bielenberg (MT) - has a paralithic contact between depths of 100 to 152 cm
Bitterroot (MT) - has a paralithic contact between depths of 50 to 100 cm
Bookcliff (UT) - has calcium carbonate present
Burtoner (MT) - has a paralithic contact at 50 to 96 cm
Clancy (MT) - has a lithic contact above a depth of 152 cm
Dooley (MT) - has calcium carbonate present.
Doughty (MT) - has horizons of secondary carbonate accumulation
Empedrado (CO) - has calcium carbonate present
Fairfield (MT) - has calcium carbonate present
Farnuf (MT) - has calcium carbonate present
Farside (MT) - ustic bordering on udic moisture regime
Felor (SD) - has calcium carbonate present
Greenway (SD) - has calcium carbonate present
Gurney (SD) - has a lithic contact between depths of 50 to 100 cm
Hangdo (UT) - has hues redder than 10YR throughout the profile; has pHs that are mildly to moderately alkaline
Hoppers (MT) - has a lithic contact at 50 to 100 cm
Howbert (CO) - has horizons of secondary calcium carbonate accumulation
Hyalite (MT) - has a lithologic discontinuity of sandy-skeletal material below the argillic horizon
Jeffcity (MT) - has a paralithic contact of grus at depths of 50 to 96 cm; has a lithic contact of granite at depths of 58 to 100 cm
Kokoruda (MT) - has an O horizon
Livona (ND) - has calcium carbonate present
Martinsdale (MT) - has calcium carbonate present
Maudlin (CO) - has a lithic contact between depths of 50 to 100 cm
Meagher (MT) - has a calcic horizon
Moen (CO) - has a lithic contact between depths of 50 to 100 cm
Moento (CO) - has a lithic contact at 50 to 100 cm
Perrypark (CO) - has hues 5YR and redder in the Bt horizons
Pianohill (MT) - has a lithic contact at depths of 50 to 100 cm
Placerton (MT) - has a lithic contact above a depth of 152 cm
Reeder (ND) - has a paralithic contact between depths of 50 to 100 cm
Reedwest (MT) - has a paralithic contact at 50 to 100 cm
Sipple (MT) - has horizons of secondary carbonate accumulation
Snakejohn (UT) - has a lithic contact at 100 to 152 cm
Sponseller (AZ) - has hues redder than 10YR throughout the profile; has less than 45 percent sand in the argillic horizon
Trag (CO) - has hues as red as 7.5YR
Tragmon (CO) - has C horizons; formed in material from shale and sandstone at elevations above 2,164 meters
Trazuni (NM) - has redox concentrations at 90 to 125 cm
Trujillo (CO) - has horizons of secondary carbonate accumulation
Ulrant (WY) - has calcium carbonate present
Vida (MT) - has horizons of secondary carbonate accumulation
Watne (MT) - has horizons of secondary carbonate accumulation
Watrous (ND) - has a lithic contact between depths of 50 to 100 cm
Wemple (MT) - has a lithic contact between 100 to 152 cm
Williams (ND) - has calcium carbonate present
Yegen (MT) - has calcium carbonate present

GEOGRAPHIC SETTING:
Landform - mountains, hills, fan remnants, alluvial fans, stream terraces and outwash fans
Elevation - 1,066 to 2,015 meters
Slope - 0 to 60 percent
Parent material - alluvium or outwash derived mainly from granite and other coarse grained igneous rocks
Climate - long, cold winters; moist springs; warm, dry summers
Mean annual precipitation - 365 to 485 mm
Mean annual air temperature - 2.2 to 7.8 degrees C.
Frost free period - 70 to 110 day

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Sawbuck and Sawicki soils. These soils are loamy-skeletal and are on similar landform positions.

DRAINAGE AND PERMEABILITY: Well drained, moderate permeability in the argillic horizon and moderately rapid below.

USE AND VEGETATION: Clasoil soils are primarily used for rangeland and wildlife habitat. The potential native vegetation is Idaho fescue, bluebunch wheatgrass, rough fescue, Sandberg bluegrass, mountain big sagebrush, and rubber rabbitbrush.

DISTRIBUTION AND EXTENT: Clasoil soils are of limited extent in southwestern Montana. MLRAs 43B, 44B.

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

SERIES ESTABLISHED: Powell County, Montana, 1995. Series proposed: Jefferson County, Montana, 1993.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 33 cm (A1, A2 horizons)
Argillic horizon - from 33 to 86 cm (Bt1, Bt2 horizons)
Particle-size control section - from 33 to 83 cm (Bt1, Bt2 horizon)

Clasoil soils have a frigid temperature regime and an ustic moisture regime.

Additional Data: Soil interpretation records: MT1531, MT3011.

National Cooperative Soil Survey
U.S.A.