LOCATION COSELY MT
Tentative Series
Rev. PHO-JMS-RJS
05/2017
COSELY SERIES
The Cosely series consists of very deep, excessively drained that formed in volcanic ash over alluvium, outwash, colluvium and till from mixed metasedimentary sources. These soils are on alluvial fans, outwash terraces, lateral moraines and glacial-valley walls. Slopes are 4 to 35 percent. Mean annual precipitation is about 1,225 mm and mean annual air temperature is about 4.0 degrees C.
TAXONOMIC CLASS: Sandy-skeletal, isotic, frigid Andic Eutrudepts
TYPICAL PEDON: Cosely gravelly ashy loam, in coniferous forest. This profile was described on an 8 percent slope at 979 meters elevation. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 4 cm; slightly decomposed forest litter
Oe--4 to 8 cm; moderately decomposed forest litter
E--8 to 10 cm; grayish brown (10YR 5/2) gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and nonplastic; many very fine roots and common fine and medium roots; common very fine irregular pores; 15 percent gravel; moderately acid (pH 6.0); clear smooth boundary.
Bw1--10 to 26 cm; yellowish brown (10YR 5/4) gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, and common fine and medium roots; common very fine irregular pores; 20 percent gravel; moderately acid (pH 6.0); clear smooth boundary.
Bw2--26 to 38 cm; light yellowish brown (10YR 6/4) gravelly ashy loam, dark yellowish brown (10YR 4/4) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine, fine and medium roots; common very fine irregular pores; 25 percent gravel, 5 percent cobbles; moderately acid (pH 6.0); gradual smooth boundary.
2C1--38 to 49 cm; light yellowish brown (10YR 6/4) very gravelly coarse sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; 40 percent gravel, 15 percent cobbles; slightly acid (pH 6.2).
2C2--49 to 152 cm; light yellowish brown (10YR 6/4) extremely gravelly coarse sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; 50 percent gravel, 15 percent cobbles; slightly acid (pH 6.2).
TYPE LOCATION: Glacier County, Montana; 588 meters south and 317 meters east of the NW corner of Sec. 23, T. 33 N, R. 18 W; Lake McDonald West topographic quadrangle; Latitude - 48 degrees, 36 minutes, 41 seconds north; Longitude - 113 degrees, 52 minutes, 51 seconds west.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 3.0 to 7.0 degrees C.
Volcanic ash mantle thickness - 18 to 36 cm
Depth to cambic horizon - 6 to 12 cm
Oi, Oe horizons
Thickness: 4 to 10 cm (combined thickness of Oi, Oe)
E horizon
Hue: 10YR or 7.5YR dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 1 to 4 dry or moist
Texture, less than 2mm fraction: medial loam or medial sandy loam
Clay content: 8 to 20 percent
Rock fragments: 15 to 30 percent--10 to 30 percent gravel; 0 to 5 percent cobbles
Reaction: pH 5.9 to 7.0
Thickness: 1 to 8 cm
Bw1, Bw2 horizons
Hue: 10YR or 7.5YR dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 1 or 4 dry or moist
Texture, less than 2mm fraction: medial loam or medial sandy loam
Clay content: 8 to 20 percent
Rock fragments: 15 to 35 percent--10 to 35 percent gravel; 0 to 5 percent cobbles
Reaction: pH 5.9 to 7.0
Thickness: 16 to 36 cm (combined thickness of Bw1, Bw2)
2C1, 2C2 horizons
Hue: 10YR, 7.5YR or 5YR dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 6 dry or moist
Texture, less than 2mm fraction loamy sand, sand or coarse sand
Clay content: 1 to 8 percent
Rock fragments: 50 to 85 percent--40 to 65 percent gravel; 10 to 25 percent cobbles; 0 to 5 percent stones
Reaction: pH 6.0 to 7.0
Thickness (2C1, 2C2 combined): 100 cm or more
COMPETING SERIES: No competing series.
GEOGRAPHIC SETTING:
Landform - alluvial fans, outwash terraces, lateral moraines and glacial-valley walls
Elevation - 950 to 1,500 meters
Slope - 2 to 35 percent
Parent material - volcanic ash over alluvium, outwash, colluvium and till from mixed metasedimentary sources
Climate - long, cold winters; moist springs; short warm summers
Mean annual precipitation - 825 to 1650 mm
Mean annual air temperature - 2.0 to 6.0 degrees C.
Frost-free period - 70 to 95 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Excessively drained; 5 to 15 um/sec in the surface layer and 15 to 150 um/sec below.
USE AND VEGETATION: Recreation, woodland and wildlife habitat. Vegetation is dominated by western red cedar, western hemlock, western larch and white pine with queen's cup bead lily, twin flower, rattlesnake plantain, and one sided wintergreen in the understory.
DISTRIBUTION AND EXTENT: Cosely soils are of small extent in northwestern Montana. MLRA 43A and 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Glacier National Park area in Glacier County, Montana, 2015. The series name is derived from a local landmark.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic subgroup - from 8 to 38 cm (E, Bw1, Bw2 horizons)
Cambic horizon - from 10 to 38 cm (Bw1, Bw2 horizons)
Particle-size control section - from 33 to 108 cm (part of the Bw2, 2C1, part of 2C2 horizons).
Cosely soils have a frigid temperature regime and an udic moisture regime.
Taxonomic version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.