LOCATION NEMESIS MT
Established Series
REV. KTS-RJS
01/2012
NEMESIS SERIES
The Nemesis series consists of very deep, somewhat excessively drained soils that formed in slide deposits and colluvium derived from mixed metamorphic and sedimentary rock. These soils occur on avalanche chutes and mountain slopes. Slopes are 40 to 80 percent. Mean annual precipitation is about 800 mm, and the mean annual air temperature is about 3 degrees C.
TAXONOMIC CLASS: Loamy-skeletal over fragmental, mixed, superactive Pachic Haplocryolls
TYPICAL PEDON: Nemesis gravelly loam, in forest on a 65 percent north slope at an elevation of 2317 meters (Colors are for dry soil unless otherwise noted).
Oi--0 to 3 cm; slightly decomposed forest litter; clear smooth boundary. (3 to 8 cm thick)
A--3 to 21 cm; dark brown (7.5YR 3/2) gravelly loam, very dark brown (7.5YR 2.5/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; many very fine and fine irregular pores; 20 percent gravel and 5 percent cobbles; neutral (pH 7.0); clear smooth boundary. (16 to 25 cm thick)
Bw--21 to 48 cm; brown (7.5YR 4/2) very gravelly fine sandy loam, very dark brown (7.5YR 2.5/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; many very fine and fine irregular pores; 40 percent gravel and 5 percent cobbles; neutral (pH 7.2); gradual wavy boundary. (24 to 36 cm thick)
BC--48 to 68 cm; brown (7.5YR 4/2) extremely gravelly fine sandy loam, dark brown (7.5YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, and common medium and coarse roots; common fine irregular pores; 75 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.4); abrupt wavy boundary. (15 to 30 cm thick)
C--68 to 152 cm; brown (7.5YR 5/3) extremely gravelly loamy sand, dark brown (7.5YR 3/3) moist; single grain; loose, nonsticky and nonplastic; about half of volume not occupied by rock fragments are voids; few coarse roots; 85 percent gravel, 5 percent cobbles and 5 percent stones; neutral (pH 7.2).
TYPE LOCATION: Beaverhead County, Montana; located 700 meters east and 265 meters south of the northwest corner of sec. 25, T. 14 S., R 1 E; Mount Jefferson topographic quadrangle; UTM 12T, 456394e., 4937488n. NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 1 to 4 degrees C.
Thickness of the mollic epipedon - 40 to 70 cm
Depth to fragmental layer - 50 to 100 cm
A horizon
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 12 to 18 percent
Rock fragments: 15 to 35 percent--15 to 35 percent gravel, 0 to 10 percent cobbles, and 0 to 10 percent stones
Reaction: pH 6.4 to 7.6
Bw horizon
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam or fine sandy loam
Clay content: 10 to 18 percent
Rock fragments: 35 to 75 percent--35 to 75 percent gravel, 0 to 10 percent cobbles, and 0 to 10 percent stones
Reaction: pH 6.4 to 7.6
BC horizons
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam or fine sandy loam
Clay content: 10 to 18 percent
Rock fragments: 60 to 85 percent--60 to 80 percent gravel, 0 to 10 percent cobbles, and 0 to 10 percent stones
Reaction: pH 6.4 to 7.6
C horizon
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 2 or 3; dry or moist
Texture: sand or loamy sand
Clay content: 0 to 10 percent
Rock fragments: 85 to 95 percent--75 to 90 percent gravel, 0 to 10 percent cobbles, and 0 to 10 percent stones
Reaction: pH 6.4 to 7.6
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - avalanche chutes and mountain slopes
Elevation - 2175 to 2930 meters
Slope - 40 to 80 percent
Parent material - slide deposits and colluvium derived from mixed metamorphic and sedimentary rock
Climate - long, cold winters; moist springs; short warm summers
Mean annual precipitation - 750 to 1150 mm
Mean annual air temperature - 1 to 4 degrees C.
Frost-free period - 30 to 50 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained and moderately rapid over rapid permeability.
USE AND VEGETATION: Nemesis soils are used mainly for wildlife and recreation. The vegetation is mainly Douglas-fir, subalpine fir, lodgepole pine, whitbark pine, snowberry, buffaloberry, spirea, heartleaf arnica, pinegrass, elk sedge and other miscellaneous grasses and forbs.
DISTRIBUTION AND EXTENT: Nemesis soils are of limited 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, 2010.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 3 to 48 cm (A and Bw horizons)
Fragmental layer - from 68 to 152 cm (C horizon)
Particle-size control section - from 28 to 103 cm (part of Bw, BC and part of C horizons)
Nemesis soils have a cryic temperature regime and an udic moisture regime.
Taxonomic version: Eleventh Edition, 2010.
National Cooperative Soil Survey
U.S.A.