LOCATION CORMOL CA+NVEstablished Series
TAXONOMIC CLASS: Ashy, glassy, mesic, shallow Vitritorrandic Argixerolls
TYPICAL PEDON: Cormol very cobbly ashy loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; light brownish gray (10YR 6/2) very cobbly ashy loam, very dark grayish brown (10YR 3/2) moist; strong thick platy structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine roots; many very fine and common fine vesicular pores; 10 percent gravel, 20 percent cobbles, and 10 percent stones; neutral (pH 6.8); clear wavy boundary. (1 to 3 inches thick)
A2--3 to 7 inches; brown (10YR 5/3) ashy loam, dark brown (10YR 3/3) moist; strong thin platy structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine and common fine roots; many very fine vesicular pores; 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (3 to 5 inches thick)
Bt1--7 to 11 inches; grayish brown (10YR 5/2) ashy sandy clay loam, very dark grayish brown (10YR 3/2) moist; strong fine and medium subangular blocky structure; slightly hard, very friable, sticky and plastic; common very fine and fine roots; many very fine tubular pores; common faint and distinct clay films on faces of peds and lining pores; 10 percent gravel; neutral (pH 7.2); clear wavy boundary. (4 to 7 inches thick)
Bt2--11 to 18 inches; yellowish brown (10YR 5/4) very paragravelly ashy sandy clay loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, sticky and plastic; common very fine and fine roots; many very fine tubular pores; many faint and common distinct clay films on faces of peds and lining pores; 40 percent paragravel; slightly alkaline (pH 7.4); clear irregular boundary. (5 to 9 inches thick)
Cr--18 to 34 inches; pale yellow (2.5Y 8/2) soft, weathered andesitic tuff; few roots and soil in some fractures; slightly alkaline (pH 7.8).
TYPE LOCATION: Lassen County, California; near Upper Tuledad Canyon; approximately 950 feet west and 200 feet south of the northeast corner of section 31, T. 37 N., R. 17 E.; USGS Little Hat Mountain 7.5 minute topographic quadrangle; 41 degrees 02 minutes 09.7 seconds north latitude and 120 degrees 04 minutes 48.1 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Moist in winter and spring, dry from June through October; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 47 to 51 degrees F.
Mollic epipedon thickness - 8 to 12 inches; includes the Bt1 horizon.
Depth to bedrock - 14 to 20 inches to a paralithic contact. The paralithic materials below the contact are vitric tuffs.
Volcanic glass content - 35 to 60 percent in the coarse silt through fine sand fractions.
Particle-size control section - Clay content: 20 to 30 percent;
Rock fragments: Averages 15 to 30 percent paragravel and 0 to 15 percent gravel. Lithology of fragments are volcanic rocks such as tuff.
A horizons
Value: 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 2.5 percent.
Bt1 horizon
Hue: 10YR or 7.5YR.
Value: 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: Ashy sandy clay loam, ashy loam, or ashy clay loam.
Rock fragments: 5 to 15 percent gravel.
Reaction: Neutral or slightly alkaline.
Organic matter content: 1 or 2 percent.
Bt2 horizon
Hue: 10YR or 7.5YR.
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very paragravelly ashy sandy clay loam, very paragravelly ashy clay loam, and paragravelly ashy loam.
Pararock fragments: 30 to 45 percent paragravel.
Rock fragments: 0 to 15 percent gravel.
Reaction: Neutral or slightly alkaline.
COMPETING SERIES: These are the Ashcamp and Okayview series.
Ashcamp soils have 10 to 18 percent clay in the argillic horizon and are 7 to 14 inches deep. Okayview soils are intermittently moist for 10 to 20 days cumulative from July to September due to convection storms.
GEOGRAPHIC SETTING: Cormol soils are on plateaus. They formed in volcanic ash and residuum derived from andesitic tuff and similar volcanic rocks of pyroclastic origin. Slopes are 15 to 50 percent. Elevations range from 4,820 to 7,000 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 10 to 12 inches, the mean annual temperature is 45 to 47 degrees F., and the frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bucklake, Devada, and Dosie soils. Bucklake soils are moderately deep and fine textured. Devada soils are clayey and shallow to lithic contacts. Dosie soils are deep and clayey-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderate permeability (moderately high or high saturated hydraulic conductivity).
USE AND VEGETATION: Cormol soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, bluebunch wheatgrass, and Thurber's needlegrass.
DISTRIBUTION AND EXTENT: Northeastern California and northwestern Nevada. These soils are not extensive with about 6,200 acres of the series mapped to date. MLRA 23.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Surprise Valley-Home Camp Area, California-Nevada, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 11 inches (A1, A2, and Bt1 horizons).
Argillic horizon - The zone from 7 to 18 inches (Bt1 and Bt2 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 18 inches (A1, A2, Bt1, and Bt2 horizons).
Paralithic contact - The boundary at 18 inches to underlying soft bedrock (Cr layer).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 7 to 18 inches (Bt1 and Bt2 horizons).