LOCATION JIMLAKE MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Andic Glossocryalfs
TYPICAL PEDON: Jimlake gravelly ashy silt loam, forested. (Colors are for dry soil unless otherwise noted.)
0i--0 to 2 inches; decomposed and slightly decomposed forest litter.
E--2 to 3 inches; light gray (10YR 7/2) gravelly ashy silt loam, grayish brown (10YR 5/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine, medium and coarse roots; many fine pores; 20 percent pebbles; moderately acid (pH 6.0); clear smooth boundary. (0 to 3 inches thick)
Bw--3 inch to 9 inches; brown (7.5YR 5/4) gravelly ashy silt loam, brown (7.5YR 4/4) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine, medium, and coarse roots; many fine pores; 20 percent pebbles; moderately acid (pH 5.7); clear wavy boundary. (7 to 10 inches thick)
2Bt/E--9 to 16 inches; B part (about 65 percent) is light yellowish brown (10YR 6/4) gravelly silt loam, yellowish brown (10YR 5/6) moist; E part (35 percent) is very pale brown (10YR 7/3) gravelly silt loam, pale brown (10YR 6/3) moist; that interfingers into the B part; texture mixed is gravelly silt loam; weak medium and coarse subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common fine and medium roots; many fine pores; 25 percent pebbles; slightly acid (pH 6.5); clear wavy boundary. (4 to 10 inches thick)
2Bt1--16 to 26 inches; light yellowish brown (10YR 6/4) very gravelly silt loam, yellowish brown (10YR 5/6) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine roots; many fine pores; common distinct clay films on faces of peds; 35 percent pebbles; slightly acid (pH 6.4); clear wavy boundary. (8 to 12 inches thick)
2Bt2--26 to 40 inches; light yellowish brown (10YR 6/4) very gravelly silt loam, yellowish brown (10YR 5/6) moist; moderate fine subangular blocky structure; hard, friable, slightly sticky and slighty plastic; common fine roots; many fine pores; common thin clay films on faces of peds; 40 percent pebbles; neutral (pH 6.9); gradual wavy boundary. (10 to 20 inches thick)
BC--40 to 60 inches; light yellowish brown (2.5Y 6/4) very gravelly silt loam, light olive brown (2.5Y 5/4) moist; weak coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine roots; common fine pores; 10 percent cobbles, 35 percent pebbles; neutral (pH 7.2).
TYPE LOCATION: Missoula County, Montana; 1,100 feet west and 900 feet north of the center of sec. 8, T. 20 N., R. 17 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 39 to 44 degrees F.
Moisture control section - approximately between the depths of 4 and 12 inches.
Control section - 10 to 20 percent clay
Rock fragments - 35 to 60 percent in the control section
Depth to carbonates - mainly below 60 inches, but ranges to 40 inches
E horizon - Hue: 10YR to 7.5YR
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Clay content: 7 to 15 percent
Rock fragments: 15 to 35 percent--0 to 5 percent cobbles and stones; 15 to 30 percent pebbles
Reaction: pH 5.6 to 6.5
Moist bulk density: 0.95 g/cc or less
Bw horizon - Hue: 10YR or 7.5YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 or 6
Clay content: 7 to 15 percent
Rock fragments: 15 to 35 percent--0 to 5 percent cobbles and stones, 15 to 30 percent pebbles
Reaction: pH 5.6 to 6.5
Moist bulk density: 0.95 g/cc or less
NOTE: Some pedons may have a thin E/B horizon.
2Bt/E horizon - Hue: B part 2.5Y or 10YR; E part 2.5Y or 10YR
Value: B part 5 or 6, E part 6 or 7 dry; B part 4 or 5, E part 5 or 6 moist
Chroma: B part 3, 4, or 6; E part 2, 3, or 4
Texture (mixed), less than 2 mm: silt loam or loam
Clay content: 10 to 18 percent
Rock fragments: 15 to 35 percent--0 to 5 percent cobbles and stones; 15 to 30 percent pebbles
Reaction: pH 6.1 to 7.3
2Bt horizons - Hue: 2.5Y or 10YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 or 6
Texture, less than 2 mm: silt loam or loam
Clay content: 13 to 20 percent
Rock fragments: 35 to 60 percent--0 to 10 percent cobbles and stones; 35 to 50 percent pebbles
Reaction: pH 6.1 to 7.3
BC horizon - Hue: 2.5Y or 10YR
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 3 or 4
Texture, less than 2 mm: silt loam or loam
Clay content: 10 to 18 percent
Rock fragments: 35 to 60 percent--0 to 10 percent cobbles and stones; 35 to 50 percent pebbles
Reaction: pH 6.6 to 7.8
NOTE: This horizon is not present in some pedons.
COMPETING SERIES: This is the Bata series. Bata soils have a very hard and firm argillic horizon that is 20 to 35 percent clay.
GEOGRAPHIC SETTING: Jimlake soils are on moraines in glaciated valleys and on mountain slopes. Elevation are 3,800 to 6,000 feet. Slopes are 4 to 60 percent. These soils formed in glacial till and have a large component of volcanic ash in the surface layer. The climate is characterized by long, cold winters and moist springs. Mean annual precipitation is 30 to 40 inches, much of which falls as snow or as spring rain. Mean annual temperature is 37to 42 degrees F. The frost-free period is less than 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
DRAINAGE AND PERMEABILITY: Well drained, slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Jimlake soils are used for timber production and watersheds and as wildlife habitat. The native vegetation is subalpine fir, western larch, Douglas-fir, Engelmann spruce, western red cedar, western whitepine, and lodgepole pine with an understory of blue huckleberry, queencup beadlily, twinflower, common beargrass, and Pacific yew.
DISTRIBUTION AND EXTENT: Jimlake soils are of moderate extent in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Missoula County, Montana 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 9 inches (Oi, E, Bw horizons);
Argillic horizon - 9 to 40 inches (2Bt/E, 2Bt1, 2Bt2, horizons);
Particle-size control section - upper 20 inches of the argillic horizon.
Jimlake soils have a cryic temperature regime and a udic moisture regime.