LOCATION LOSTLAKE COEstablished Series
TAXONOMIC CLASS: Loamy, isotic Lithic Dystrocryepts
TYPICAL PEDON: Lostlake loam, on a south facing, simple, 40 percent slope in spruce-fir woodland at an elevation of 10,900 feet. (Colors are for dry soil unless otherwise noted.) Described on September 18, 1980.
Oi--0 to 2 inches; organic layer of needles and leaves. (1 to 3 inches thick)
A--2 to 6 inches; reddish gray (5YR 5/2) loam, dark reddish gray (5YR 4/2) moist; moderate fine granular structure; slightly hard, friable, nonsticky and nonplastic; 10 percent gravel; very strongly acid (pH 4.8); clear smooth boundary. (2 to 5 inches thick)
Bw--6 to 15 inches; light reddish brown (5YR 6/4) gravelly sandy clay loam reddish brown (5YR 4/4) moist; moderate medium granular structure; slightly hard, very friable, nonsticky and slightly plastic; 20 percent gravel; very strongly acid (pH 4.6); abrupt smooth boundary. (6 to 15 inches thick)
R--15 inches; granite bedrock, fractured in upper few inches.
TYPE LOCATION: La Plata County, Colorado; about 20 miles northeast of Durango; located about 2,600 feet west and 2,200 feet south of the northeast corner of sec. 9, T. 37 N., R. 7 W.; Lemon Reservoir USGS quad; lat. 37 degrees 29 minutes 07 seconds N. and long. 107 degrees 38 minutes 58 seconds W., NAD 27
RANGE IN CHARACTERISTICS: (depths given are measured from the mineral soil surface)
Soil moisture regime: udic; dry in some part of the moisture control section for less than 45 cumulative days (typic udic subclass)
Mean annual soil temperature: 34 to 38 degrees F.
Mean summer soil temperature: 43 to 47 degrees F., with an O horizon
Depth to lithic contact: 8 to 20 inches to granite
Depth to cambic horizon: 2 to 5 inches
Lithology of rock fragments: granite
Particle-size control section:
Clay content: 20 to 27 percent
Rock fragment content: 15 to 35 percent
A horizon:
Hue: 5YR or 7.5YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 2 or 3, dry and moist
Rock fragment content: 5 to 15 percent gravel
Base saturation: estimated at 40 to 60 percent
Reaction: very strongly acid or strongly acid
Bw horizon:
Hue: 2.5YR or 5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 6, dry and moist
Texture, fine earth fraction: SCL or L
Clay content: 20 to 27 percent
Rock fragments content: 15 to 35 percent, mostly gravel
Base saturation: estimated at 40 to 60 percent
Reaction: very strongly acid or strongly acid
COMPETING SERIES: There are currently no competitors. A similar soil is the
Granturk series.
Granturk soils: have rock fragments of sandstone lithology
GEOGRAPHIC SETTING:
Parent material: residuum and slope alluvium derived from granite.
Landform: mountain slopes.
Slopes: 30 to 80 percent
Elevation: 9,000 to 11,500 feet
Mean annual temperature: 32 to 38 degrees F.
Mean annual precipitation: 30 to 45 inches.
Wettest months: July and August receive slightly more precipitation than other months.
Driest months: May and June receive the least precipitation, however the soils are still moist from snowmelt.
Frost-free period: 40 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Frisco, Horsethief and Sig series. All are on mountain slopes.
Frisco and
Horsethief soils are very deep.
Sig soils have more than 35 percent rock fragments in the particle size control section.
DRAINAGE AND PERMEABILITY: well drained, high runoff, moderate permeability.
USE AND VEGETATION: These soils are used for timber production, recreation, and wildlife habitat. The native vegetation is Engelmann's spruce, subalpine fir, Rocky Mountain Douglas fir, quaking aspen, whortleberry, elk sedge, Thurber's fescue, wood rush, and wild rose.
DISTRIBUTION AND EXTENT: Southwestern Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: La Plata County, Animas-Dolores Soil Survey Area, Colorado, 1999. The name is taken from a lake in the area.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 2 to 6 inches. (A horizon)
Cambic horizon: The zone from 6 to 15 inches. (Bw horizon)
Lithic contact: The contact with hard bedrock at 15 inches. (R layer)
Particle size control section: The zone from 2 to 15 inches. (A and Bw horizons)
Keys to Soil Taxonomy, classified according to the Eighth Edition, 1998.
The isotic mineralogy class is estimated from data on similar soils. It is presumed to result from the significant amount of iron and aluminum oxides in this pedon.