LOCATION LIZARDHEAD COEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic Alfic Argicryolls
TYPICAL PEDON: Lizardhead loam, on an east facing, convex ridge summit, 5 percent slope, under seral aspen woodland at an elevation of 9,320 feet. (colors are for dry soil unless otherwise noted, described on September 17, 1985)
Oi--0 to 2 inches; mat of slightly decomposed aspen leaves, twigs, and grasses (0 to 3 inches thick)
A--2 to 12 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 5 percent cobbles; slightly acid (pH 6.4); clear wavy boundary. (10 to 15 inches thick)
E--12 to 24 inches; light brownish gray (10YR 6/2) sandy clay loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 5 percent gravel, 5 percent cobbles; neutral (pH 6.8); clear wavy boundary. (7 to 13 inches thick)
Bt1--24 to 43 inches; olive brown (2.5Y 4/4) very cobbly clay, dark olive brown (2.5Y 3/3) moist; strong medium angular blocky structure; hard, firm, very sticky and very plastic; common distinct clay films on faces of peds; 10 percent gravel, 25 percent cobbles, 5 percent stones; neutral (pH 6.8); gradual wavy boundary.
Bt2--43 to 66 inches; light olive brown (2.5Y 5/4) very cobbly clay, dark olive brown (2.5Y 3/3) moist; strong medium angular blocky structure; hard, firm, very sticky and very plastic; common distinct clay films on faces of peds; 20 percent gravel, 25 percent cobbles, 5 percent stones; neutral (pH 6.8). (combined thickness of the Bt horizon is 37 to 43 inches)
TYPE LOCATION: San Miguel County, Colorado; about 8 miles south of Placerville, Colorado; located about 800 feet north and 1,200 feet west of the southeast corner of Section 15, T. 42 N., R. 11 W.; USGS Little Cone topographic quadrangle; latitude 37 degrees, 53 minutes, 54 seconds north and longitude 108 degrees, 03 minutes, 40 seconds west, NAD 1927.
RANGE IN CHARACTERISTICS:
Depths in this section are measured from the top of the mineral soil surface.
Soil moisture regime: udic.
Mean annual soil temperature: 36 to 43 degrees F.
Thickness of mollic epipedon: 10 to 15 inches.
Depth to top of argillic horizon: 17 to 23 inches.
Particle-size control section:
Clay content: 35 to 50 percent
Rock fragment content: 35 to 55 percent
A horizon:
Hue: 10YR or 2.5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3 dry or moist
Rock fragments: granogabbro, granodiorite, or rhyolite; 0 to 10 percent total rock fragments; 0 to 10 percent gravel, 0 to 10 percent cobbles.
Reaction: slightly acid (pH 6.1) to neutral (pH 7.3)
E horizon (albic horizon):
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 2 or 3 dry or moist
Texture: L, SCL, GR-SCL, CB-SCL
Clay content: 25 to 32 percent.
Rock fragments: granogabbro, granodiorite, or rhyolite. 5 to 25 percent total rock fragments, 0 to 15 percent gravel, 0 to 15 percent cobbles.
Reaction: slightly acid (pH 6.1) to neutral (pH 7.3)
Bt horizon:
Hue: 10YR or 2.5Y
Value: 4 to 6 dry, 2 to 4 moist
Chroma: 3 or 4 dry or moist
Texture: CBV-CL, CBV-C
Rock fragments: granogabbro, granodiorite, or rhyolite. 35 to 55 percent total rock fragments, 5 to 20 percent gravel, 20 to 35 percent cobbles, 0 to 10 percent stones.
Reaction: slightly acid (pH 6.1) to neutral (pH 7.3)
COMPETING SERIES: These are the Callings, Grandmesa, and Sunshine series. The Callings soils have hues redder than 10YR in the argillic horizon. The Grandmesa soils have a lithic contact between 20 and 40 inches. The Sunshine soils have a fragmental substratum.
GEOGRAPHIC SETTING: The Lizardhead soils formed in slope alluvium and colluvium from granogabbro, granodiorite, or rhyolite as sills and dikes in shale of the Mancos formation on summits and backslopes of ridges and mountains. Slopes range from 5 to 65 percent. Elevation ranges from 8,800 to 10,800 feet. The mean annual temperature is about 33 to 41 degrees F. The mean annual precipitation is about 25 to 33 inches. The frost-free period is 50 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baird Hollow, Gothic, and Mountpoor soils. The Baird Hollow soils are on footslopes of mountains and have an argillic horizon that begins deeper than 24 inches. The Gothic soils are on backslopes and toeslopes of ridges and mountains and contain less than 35 percent rock fragments in the particle-size control section. The Mountpoor soils are on the backslopes and footslopes of mountains and ridges and have an argillic horizon that begins deeper than 24 inches.
DRAINAGE AND PERMEABILITY: well drained; high runoff; slow permeability.
USE AND VEGETATION: This soil is used for livestock grazing and wood products. Native vegetation is currently seral aspen with an understory of slender wheatgrass, elk sedge, blue wildrye, aspen peavine, and common juniper. Potential native vegetation is Engelmann spruce and subalpine fir with an understory of elk sedge, dwarf blueberry, common juniper, and kinnikinnick. It is in the Engelmann Spruce-Subalpine Fir Woodland Site, Forest Cover Type 206.
DISTRIBUTION AND EXTENT: Southwest Colorado in LRR E and MLRA 48A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Ouray Soil Survey Area, Uncompahgre National Forest, San Miguel County, Colorado, 1998. The name comes from Lizard Head Pass and Lizard Head Peak.
REMARKS: Diagnostic horizons and features recognized in this pedon.
Mollic epipedon: The zone from 2 to 12 inches. (A horizon)
Albic horizon: The zone from 12 to 24 inches. (E horizon)
Argillic horizon: The zone from 24 to 66 inches. (Bt1 and Bt2 horizons)
This pedon does not have an abrupt textural change.
This pedon was classified in accordance with Keys to Soil Taxonomy, 7th Edition, 1996.