LOCATION BADROCK                 CA

Established Series
Rev. EWB-AMB-TM-JVC
02/2017

BADROCK SERIES

The Badrock series consists of shallow, well drained soils that formed in residuum and colluvium derived from rhyolitic or andesitic rocks with surficial additions of eolian volcanic ash. Badrock soils are on hills and mountains. Slopes are 30 to 50 percent. The mean annual precipitation is about 380 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Aridic Lithic Argixerolls

TYPICAL PEDON: Badrock extremely gravelly ashy sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 65 percent gravel, 5 percent cobbles, 10 percent stones, and 2 percent boulders.

A1--0 to 3 cm; grayish brown (10YR 5/2) extremely gravelly ashy sandy loam, dark brown (10YR 3/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 65 percent subangular gravel; neutral (pH 6.8); clear smooth boundary. (3 to 8 cm thick)

A2--3 to 5 cm; grayish brown (10YR 5/2) gravelly ashy loam, dark brown (7.5YR 3/3) moist; moderate medium platy structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots; common very fine interstitial pores; 25 percent subangular gravel; neutral (pH 6.8); clear wavy boundary. (0 to 8 cm thick)

Bt1--5 to 10 cm; brown (7.5YR 5/2) very gravelly ashy loam, dark brown (7.5YR 3/3) moist; weak fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and fine roots; many very fine interstitial and common very fine tubular pores; 5 percent faint clay bridges between sand grains; 45 percent subangular gravel; neutral (pH 6.8); clear wavy boundary. (5 to 20 cm thick)

Bt2--10 to 18 cm; brown (7.5YR 5/2) very gravelly ashy sandy clay loam, dark brown (7.5YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and fine roots; common very fine interstitial and common very fine tubular pores; 25 percent distinct clay films on faces of peds and lining pores; 40 percent subangular gravel; slightly acid (pH 6.5); clear wavy boundary. (8 to 20 cm thick)

Bt3--18 to 38 cm; brown (7.5YR 5/2) very gravelly ashy sandy clay loam, dark brown (7.5YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and fine roots; common very fine tubular and common very fine interstitial pores; 25 percent distinct clay films on faces of peds and lining pores; 40 percent subangular gravel; slightly acid (pH 6.5); abrupt irregular boundary. (0 to 20 cm thick)

R--38 to 63 cm; unweathered rhyolite bedrock.

TYPE LOCATION: Mono County, California; in the Bodie Hills about 4.8 kilometers northeast of the ghost town of Bodie; approximately 244 meters north and 762 meters east of the southeast corner of section 35, T. 5 N., R. 27 E.; USGS Kirkwood Spring 7.5 minute topographic quadrangle; latitude 38 degrees 14 minutes 38.9 seconds N and longitude 118 degrees 58 minutes 3.7 seconds W; WGS84 Decimal Degrees 38.2441389 latitude, -118.9676944 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section during winter and spring; usually dry from July through early October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 18 to 36 cm; Includes the Bt1 horizon and may also include the Bt2 horizon in some pedons.
Depth to bedrock: 36 to 50 cm to a lithic contact.

Particle-size control section - Clay content: Averages 18 to 27 percent.
Rock fragments: Averages 35 to 60 percent, mainly gravel. Lithology of rock fragments is volcanic rock such as rhyolite or andesite.

A horizons
Hue: 10YR or 7.5YR.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 40 to 70 percent in coarse silt through fine sand fractions.

Bt1 and Bt2 horizons
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry.
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly ashy loam or very gravelly ashy sandy clay loam.
Clay content: 18 to 27 percent.
Rock fragments: 35 to 60 percent.
Organic matter content: 1 to 2 percent in Bt1 horizon, 0.5 to 2 percent in the Bt2 horizon.
Reaction: Slightly acid or neutral.
Volcanic glass content: 30 to 50 percent in very fine sand and fine sand fractions.

Bt3 horizon
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry.
Chroma: 2 through 4 dry.
Texture: Very gravelly ashy loam or very gravelly ashy sandy clay loam.
Clay content: 18 to 27 percent.
Rock fragments: 35 to 60 percent.
Organic matter content: 0.5 to 1 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 30 to 50 percent in very fine sand and fine sand fractions.

COMPETING SERIES: These are the Domehill, Farepeak, Hardnut, Hardteph, and Schoolmarm series.

Domehill, Farepeak, and Hardteph soils have lithic contacts at depths of less than 36 cm. Hardnut soils average 60 to 80 percent rock fragments in the particle-size control section. Schoolmarm soils have 27 to 35 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Badrock soils are on hills and mountains. They typically occur on backslope positions. They formed in residuum and colluvium derived from andesite, rhyolite, or rhyolitic tuff with surficial additions of eolian volcanic ash. The probable sources of the volcanic ash are the Mono Craters and Long Valley Caldera in eastern California. Slopes are 30 to 50 percent. Elevations range from 2,286 to 2,720 meters. The climate is semiarid with cold, moist winters and warm, dry summers. The mean annual precipitation is 356 to 406 mm, the mean annual temperature is 6 to 8 degrees C., and the frost-free period is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bodiehill soil and the competing Domehill soil. Bodiehill soils are very deep with bedrock deeper than 152 cm and have more than 60 percent rock fragments in the particle-size control section.

DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderate permeability; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Badrock soils are used for livestock grazing, recreation, watershed, and wildlife habitat. The native vegetation is mainly mountain big sagebrush, green ephedra, Thurber's needlegrass, Indian ricegrass, prairie junegrass, bottlebrush squirreltail, and currant.

DISTRIBUTION AND EXTENT: Eastern California, in the western part of the Great Basin. These soils are not extensive. MLRA 26.

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

SERIES ESTABLISHED: Mono County (Coleville-Bridgeport Area), California, 2010.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 38 cm (A1, A2, Bt1, and Bt2 horizons).
Argillic horizon - The zone from 5 to 38 cm (Bt1, Bt2, and Bt3 horizons).
Lithic contact - The boundary at 38 cm to underlying hard, unweathered bedrock (R layer).
Particle-size control section and ashy-skeletal substitute class with glassy mineralogy - The zone from 5 to 38 cm (Bt1, Bt2, and Bt3 horizons).

Classification was updated to 11th edition on 07/2011 changed from Lithic Argixerolls to Aridic Lithic Argixerolls.

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National Cooperative Soil Survey
U.S.A.