LOCATION MCMANNAMY MTTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Inceptic Haplustalfs
TYPICAL PEDON: McMannamy gravelly silt loam, forested (colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; undecomposed needles and twigs.
E--1 to 10 inches; light gray (10YR 7/1) gravelly silt loam, grayish brown (10YR 5/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many fine and medium roots; common coarse roots; common very fine and fine dendritic tubular pores; 5 percent cobbles and 20 percent gravel; neutral (pH 7.2); clear wavy boundary. (3 to 13 inches thick)
Bt--10 to 17 inches; light yellowish brown (2.5Y 6/4) very gravelly silt loam, olive brown (2.5Y 4/4) moist; weak medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine, fine, and medium roots and few coarse roots; few very fine and fine dendritic tubular pores; common distinct discontinuous clay films on faces of peds; 5 percent stones, 5 percent cobbles and 25 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (4 to 14 inches thick)
Bk--17 to 60 inches; light gray (2.5Y 7/2) very gravelly silt loam, grayish brown (2.5Y 5/2) moist; weak medium subangular blocky structure; soft, friable, nonsticky and nonplastic; common fine and very fine roots; few very fine dendritic tubular pores; 5 percent stones, 5 percent cobbles, and 25 percent gravel; disseminated lime, many distinct lime coatings on undersides of rock fragments; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Flathead County, Montana; 500 feet north and 500 feet west of the SE corner of sec. 11, T. 27 N., R. 21 W. Lion Mountain topographic quadrangle. UTM NAD 83, Zone 11: Northing 5332107, Easting 696883.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
Control section - 15 to 30 percent clay.
Rock fragments - 35 to 60 percent in the control section.
Depth to carbonates 13 to 26 inches.
E horizon
Hue: 2.5Y or 10YR Value: 6 or 7 dry; 4 or 5 moist
Chroma: 1, 2 or 3
Clay content: 8 to 18 percent
Rock fragments: 15 to 50 percent--0 to 10 percent cobbles and stones, 15 to 40 percent gravel
Reaction: pH 6.6 to 7.6
Bt horizon
Hue: 2.5Y or 10YR Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture: silt loam or loam
Clay content: 15 to 30 percent
Rock fragments: 35 to 60 percent--0 to 20 percent cobbles and stones, 15 to 45 percent gravel
Reaction: pH 6.8 to 7.6
Bk horizon
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: silt loam or loam
Clay content: 8 to 27 percent
Rock fragments: 35 to 60 percent--0 to 20 percent cobbles and stones, 15 to 45 percent gravel
Calcium Carbonate equivalent: 15 to 40 percent
Reaction: pH 7.8 to 8.4
COMPETING SERIES: This is the Security series. Security soils are moderately deep to a paralithic contact.
GEOGRAPHIC SETTING:
Landforms - moraines in glaciated valleys and on mountain slopes.
Elevations - 2,800 to 5,400 feet.
Slopes - 4 to 60 percent.
Aspects - southerly where evapotranspiration is highest.
Parent material - formed in calcareous till.
Climate - characterized by long, cold winters; moist springs; and warm, dry summers.
Mean annual precipitation - 18 to 24 inches, most of which falls in winter and spring.
Mean annual temperature - 39 to 45 degrees F.
Frost-free period - 70 to 105 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kingspoint, Foyslake, and Jimlake series. Kingspoint soils are on convex positions on south facing slopes. They are shallow to carbonates and lack an argillic horizon. Foyslake soils are dominantly on north facing aspects below 4500 feet elevation. They have an udic moisture regime and are moderately deep to carbonates. Jimlake soils occur on concave, north sloping aspects above 4300 feet elevation. They generally have a thick ash mantle, cryic soil temperature regime, and are deep or very deep to carbonates.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: McMannamy soils are used as woodland and for understory grazing. Native vegetation is Douglas fir ,ponderosa pine, and scattered western larch with an understory of pinegrass, common snowberry, mallow ninebark, Oregon grape, rough fescue, and Idaho fescue.
DISTRIBUTION AND EXTENT: McMannamy soils are of small extent in northwestern Montana. MLRA 43A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Flathead County, Montana, 2005. The name is from McMannamy Draw in the West Valley area of the Upper Flathead Valley in Northwest Montana.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 10 inches (Oi and E horizon);
Argillic horizon - 10 to 17 inches (Bt horizon);
Calcic horizon - 18 to 60 inches (Bk horizon);
Particle-size control section - 10 to 17 inches (Bt horizon).
McMannamy soils have a frigid temperature regime and an ustic moisture regime.