LOCATION LOLOPEAK MTEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed Andic Humicryepts
TYPICAL PEDON: Lolopeak bouldery ashy loam, forested. (Colors are for dry soil unless otherwise noted.)
0i--0 to 3 inches; undecomposed and slightly decomposed forest litter.
A--3 to 12 inches; brown (10YR 4/3) bouldery ashy loam, very dark brown (10YR 2/2) moist; weak medium and coarse granular structure; soft, very friable, nonsticky, and nonplastic; many very fine, fine, and medium roots and common coarse roots; 1 percent boulders and 10 percent gravel; strongly acid (pH 5.4); clear wavy boundary. (7 to 15 inches thick)
2Bw--12 to 30 inches; yellowish brown (10YR 5/4) extremely stony loamy coarse sand, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, and nonplastic; many very fine, fine, and medium roots and common coarse roots; 10 percent stones, 10 percent cobbles, and 45 percent gravel; moderately acid (pH 6.0); gradual wavy boundary. (10 to 20 inches thick)
2C--30 to 60 inches; pale brown (10YR 6/3) extremely stony loamy coarse sand, brown (10YR 4/3) moist; single grain; loose, nonsticky, and nonplastic; few very fine and fine roots; 15 percent stones, 10 percent cobbles, and 50 percent gravel; moderately acid (pH 6.0).
TYPE LOCATION: Missoula County, Montana; 200 feet north and 800 feet west of the E 1/4 corner of sec. 34, T. 11 N., R. 22 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 35 to 38 degrees F
Moisture control section - approximately between the depths of 12 to 35 inches
Mean annual summer temperature - greater than 44 degrees F
Control section - 0 to 5 percent clay
Base saturation - less than 50 percent
A horizon - Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Clay content: 7 to 12 percent
Rock fragments: 15 to 35 percent--5 to 10 percent cobbles, stones, and boulders; 10 to 25 percent gravel
Reaction: pH 5.1 to 6.0
Bulk density: 0.95 g/cc or less
Base saturation: 20 to 50 percent
2Bw horizon - Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Clay content: 0 to 5 percent
Rock fragments: 60 to 85 percent--15 to 35 percent cobbles and stones; 45 to 50 percent gravel
Reaction: pH 5.1 to 6.0
2C horizon - Value: 6 or 7 dry; 4 or 5 moist
Chroma: 3 or 4
Clay content: 0 to 5 percent
Rock fragments: 60 to 85 percent--15 to 35 percent cobbles and stones; 45 to 50 percent grave;
Reaction: pH 5.1 to 6.0
COMPETING SERIES:
Roman (ID) - is medial in the volcanic ash mantle.
GEOGRAPHIC SETTING: Lolopeak soils are on mountain slopes. Elevations are 6,500 to 8,500 feet. Slopes are 50 to 80 percent. These soils formed in colluvium or glacial till derived from granite and gneiss. Lolopeak soils 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 45 to 80, much of which falls as snow and as spring rain. Mean annual temperature is 33 to 36 degrees F. The frost-free period is less than 40 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Excessively drained; rapid runoff; rapid permeability.
USE AND VEGETATION: Lolopeak soils are used for timber production and watersheds and as wildlife habitat. The native vegetation is subalpine fir, Engelmann spruce, lodgepole pine, whitebark pine, and alpine larch with an understory of grouse whortleberry, rusty menziesia, and smooth woodrush.
DISTRIBUTION AND EXTENT: Lolopeak soils are of small extent in western Montana and northern Idaho.
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: an umbric epipedon from the soil surface to 9 inches; a particle- size control section from 10 to 40 inches (2Bw, C horizons). Lolopeak soils have a cryic temperature regime and a udic moisture regime.
The 3/2008 description reflects a change in classification from Sandy-skeletal, mixed Andic Dystrocryepts to Sandy-skeletal, mixed Andic Humicryepts due to revision of the cryepts great groups and subgroups. The competing series section was not updated and should be reviewed after all the cryepts have been re-classified.