LOCATION SKULL CREEK             NV OR

Established Series
Rev. TSB-RLB-JBF
11/2019

SKULL CREEK SERIES

The Skull Creek series consists of moderately deep, well drained soils that formed in loess high in volcanic ash over alluvium derived from mixed rocks. The Skull Creek soils are on fan piedmonts and fan piedmonts remnants. Slopes are 0 to 8 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Vitrixerandic Haplodurids

TYPICAL PEDON: Skull Creek, ashy very fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 5 cm; pale brown (10YR 6/3) ashy very fine sandy loam, brown (10YR 4/3) moist; strong very thin platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine vesicular pores; slightly alkaline (pH 7.6); clear smooth boundary. (3 to 20 cm thick)

A2--5 to 15 cm; pale brown (10YR 6/3) ashy very fine sandy loam, brown (10YR 4/3) moist; moderate very thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, few fine and medium roots; common very fine vesicular and few very fine tubular pores; slightly alkaline (pH 7.8); clear smooth boundary. (3 to 13 cm thick)

Bw1--15 to 28 cm; light yellowish brown (10YR 6/4) ashy loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular pores; 5 percent gravel; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 13 cm thick)

Bw2--28 to 38 cm; very pale brown (10YR 7/3) gravelly ashy loam, brown (10YR 4/3) moist; weak fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular pores; 15 percent gravel; moderately alkaline (pH 8.2) abrupt smooth boundary. (8 to 20 cm thick)

Bqk1--38 to 58 cm; light gray (10YR 7/2) gravelly sandy loam, brown (10YR 4/3) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine roots; few fine tubular pores; 25 percent gravel; 15 percent 5 to 15 mm durinodes; slightly effervescent with common fine carbonate filaments; moderately alkaline (pH 8.4); clear smooth boundary. (13 to 30 cm thick)

Bqk2--58 to 86 cm; very pale brown (10YR 7/3) gravelly sandy loam, brown (10YR 4/3) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine roots, few fine tubular pores; 20 percent gravel; 25 percent 5 to 15 mm durinodes; strongly effervescent with common medium carbonate filaments; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 28 cm thick)

Bqkm--86 cm; very pale brown (10YR 8/2) indurated duripan; strongly effervescent.

TYPE LOCATION: Elko County, Nevada; approximately 3.5 miles south of Rock Creek Ranch, about 1,600 feet north and 1,600 feet west of the southeast corner of section 6, T. 36 N., R. 47 E; USGS Rock Creek Ranch 7.5 minute topographic quadrangle; latitude 41 degrees 01 minutes 24 seconds N and longitude 116 degrees 42 minutes 28.3 seconds W; WGS84 Decimal Degrees 41.0233333 latitude, -116.7078611 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in winter and spring, dry June through October; aridic bordering xeric soil moisture regime.
Mean annual soil temperature: 8 to 11 degrees C.
Depth to duripan: 50 to 100 cm.

Particle-size control section - Clay content: 8 to 18 percent.
Rock fragments: 0 to 30 percent; mainly gravel. Lithology is mixed, dominated by volcanic and tuffaceous rocks.

A horizon
Value: 6 or 7 dry, 3 or 4 moist.
Chroma: 2 or 3.
Reaction: Slightly alkaline or moderately alkaline.
Volcanic glass: Volcanic glass is estimated to range from 30 to 50 percent of the 0.2 to 2 mm fraction above 25 cm.

Bw horizons
Value: 6 or 7 dry, 3 or 4 moist.
Chroma: 3 or 4.
Texture: Ashy loam or ashy sandy loam.
Structure: Weak or moderate, fine or medium subangular blocky or it is massive.
Reaction: Moderately alkaline or strongly alkaline.
Volcanic glass: Volcanic glass is estimated to range from 20 to 30 percent of the 0.2 to 2 mm fraction.

Bqk horizons
Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 3 through 6.
Texture: Ashy loam or ashy sandy loam.
Rock fragments: 0 to 30 percent, mainly gravel.
Durinodes: 0 to 30 percent.
Reaction: Moderately alkaline or strongly alkaline.
Volcanic glass: Volcanic glass is estimated to range from 10 to 30 percent of the 0.2 to 2 mm fraction.

Bqkm horizons
Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 3 through 6.
Reaction: Moderately alkaline or strongly alkaline.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Skull Creek soils are on fan piedmonts. These soils formed in loess high in volcanic ash over alluvium derived from mixed rocks. Slopes are 0 to 8 percent. Elevations are 1,200 to 1,800 meters. The climate is cool, semiarid with warm dry summers and cool moist winters. The mean annual precipitation is 200 to 300 mm, mean annual temperature is 7 to 10 degrees C, and the frost-free season is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Shabliss and Puett soils. Shabliss soils are shallow to a duripan. Puett soils are shallow to a paralithic contact.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, very slow to medium runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, Sandburg bluegrass, bottlebrush squirreltail and Thurber needlegrass.

DISTRIBUTION AND EXTENT: Northern Nevada. MLRA 25. These soils are moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Humboldt County, Nevada, East Part, 1986.

REMARKS: December, 2008 revision changes the classification from Xeric Haplodurids to Vitrixerandic Haplodurids to accommodate the volcanic ash in soil taxonomy.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (A horizons and part of the Bw1 horizon).
Cambic horizon - The zone from 15 to 38 cm (Bw1 and Bw2 horizons).
Vitritorrandic feature - Volcanic glass is estimated to be 30 to 50 percent of the 0.02 to 2 mm fraction in the zone from 0 to 15 cm (A horizons) and 10 to 30 percent in the lower horizons (Bw and Bqk horizons).
Duripan - The zone beginning at 86 cm (Bqkm layer).
Particle-size control section - The zone from 25 to 86 cm (part of the Bw1, Bw2, Bqk1 and Bqk2 horizons).

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National Cooperative Soil Survey
U.S.A.