LOCATION BOREALIS                NV

Established Series
Rev. DJM-EWB-WED-JVC
02/2017

BOREALIS SERIES

The Borealis series consists of moderately deep to a duripan, well drained soils that formed in eolian volcanic ash and in residuum derived from basalt. Borealis soils are on plateaus. Slopes are 4 to 30 percent. The mean annual precipitation is about 330 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Ashy, glassy, frigid Abruptic Durixeralfs

TYPICAL PEDON: Borealis very cobbly ashy loamy sand--forestland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with 15 percent gravel, 15 percent cobbles, and 5 percent stones.

A1--0 to 5 cm; grayish brown (10YR 5/2) very cobbly ashy loamy sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine interstitial pores; 15 percent gravel, 15 percent cobbles, and 5 percent stones; neutral (pH 6.6); clear wavy boundary. (5 to 10 cm thick)

A2--5 to 15 cm; light brownish gray (10YR 6/2) ashy fine sandy loam, dark grayish brown (10YR 4/2) moist; moderate medium platy structure parting to moderate very fine subangular blocky; soft, very friable, nonsticky and nonplastic; common fine and medium roots; common very fine and fine interstitial pores; 5 percent gravel; neutral (pH 6.8); gradual smooth boundary. (10 to 18 cm thick)

A3--15 to 28 cm; light gray (10YR 7/2) ashy fine sandy loam, brown (10YR 5/3) moist; strong thick platy structure; soft, very friable, slightly sticky and nonplastic; common very fine through medium roots; many very fine and fine interstitial and few fine tubular and vesicular pores; 10 percent gravel; neutral (pH 7.2); abrupt wavy boundary. (10 to 20 cm thick)

Bt1--28 to 43 cm; pale brown (10YR 6/3) gravelly ashy clay loam, brown (10YR 4/3) moist; strong fine and medium angular blocky structure; hard, firm, very sticky and moderately plastic; common coarse, medium and fine roots; common very fine tubular pores; many prominent clay films on all faces of peds and lining pores; 20 percent gravel; neutral (pH 7.2); clear wavy boundary. (8 to 20 cm thick)

Bt2--43 to 58 cm; yellowish brown (10YR 5/4) ashy clay loam, dark yellowish brown (10YR 4/4) moist; strong coarse and medium angular blocky structure; hard, firm, very sticky and moderately plastic; many very fine, common fine and medium roots; common fine tubular pores; many prominent clay films on all faces of peds and lining pores; 10 percent gravel; neutral (pH 7.2); clear wavy boundary. (13 to 20 cm thick)

Bqkm--58 to 102 cm; white (10YR 8/1) cemented material, yellow (10YR 7/6) moist; massive; 3 to 6 mm indurated laminar cap over soil material that is strongly cemented by secondary silica and carbonates; 35 percent cobbles and 30 percent gravel; violently effervescent; very strongly alkaline (pH 9.6); abrupt wavy boundary. (25 to 50 cm thick)

R--102 cm; hard unweathered basalt.

TYPE LOCATION: Mineral County, Nevada; about 1 mile east of Aurora Crater; about 1,290 feet south and 650 feet east of the northwest corner of section 3, T. 5 N., R. 28 E.; USGS Mount Hicks 7.5 minute topographic quadrangle; latitude 38 degrees 19 minutes 29 seconds N and longitude 118 degrees 51 minutes 15 seconds W; WGS84 Decimal Degrees 38.3248333 latitude, -118.8375000 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring; dry from July through October; xeric moisture regime that borders on aridic.
Mean annual soil temperature: 7 to 8 degrees C.
Ochric epipedon thickness: 25 to 30 cm.
Depth to duripan: 50 to 90 cm.
Depth to bedrock: 89 to 102 cm to a lithic contact.

Particle-size control section - Clay content: 35 to 45 percent.
Rock fragments: Averages 15 to 35 percent, mainly gravel. Lithology of fragments is volcanic rocks such as basalt.

A horizons
Value: 5 through 7 dry, 4 through 6 moist.
Chroma: 2 or 3, dry or moist.
Clay content: 5 to 15 percent.
Reaction: Neutral or slightly alkaline.
Volcanic glass content: 40 to 80 percent in coarse silt through fine sand fractions.
Other features: The high content of light-colored volcanic ash does not allow these horizons to meet mollic epipedon color criteria.

Bt horizons
Value: 4 through 6 dry.
Chroma: 3 through 6, dry or moist.
Texture: Gravelly ashy clay loam, gravelly ashy clay, ashy clay loam, or ashy clay.
Clay content: 35 to 45 percent.
Rock fragments: 15 to 35 percent, mainly gravel; some pedons have subhorizons with 10 to 45 percent gravel.
Reaction: Neutral or slightly alkaline.
Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions.

Bqkm horizon
Cementation class: 3 to 6 mm thick continuous silica cemented lamina stratified with strongly cemented material between pockets of weakly cemented material in some pedons.
Rock fragments: 35 to 65 percent, mainly gravel and cobbles.
Reaction: Moderately alkaline through very strongly alkaline.

COMPETING SERIES: At present, there are no other series in this family.

GEOGRAPHIC SETTING: Borealis soils are on plateaus. These soils formed in eolian volcanic ash and in residuum derived from basalt. The probable sources of the volcanic ash are the Mono Craters and Long Valley Caldera in eastern California. Slopes are 4 to 30 percent. Elevations range from 2,010 to 2,470 meters. The mean annual precipitation is 300 to 360 mm, mean annual temperature is 6 to 7 degrees C., and the frost-free period is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Antholop and Mopana soils. Antholop soils are shallow to duripans and have a mesic temperature regime. Mopana soils are shallow to duripans and have mollic epipedons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high surface runoff; very slow permeability; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Borealis soils are used for forestland, livestock grazing, and wildlife habitat. The native vegetation is a forest canopy of singleleaf pinyon with an understory of desert bitterbrush, green ephedra, bottlebrush squirreltail, Indian ricegrass, and Wyoming big sagebrush.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are moderately extensive. MLRA 26.

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

SERIES ESTABLISHED: Mineral County (Mineral County Area), Nevada, 1985.

REMARKS: The revision of May 2001 updated the taxonomic class from Fine, mixed, frigid Abruptic Durixeralfs and corrected the type location.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 28 cm (A1, A2, and A3 horizons).
Abruptic feature - The abrupt clay increase of more than 15 percent at 28 cm (between the A3 and Bt1 horizons).
Argillic horizon - The zone from 28 to 58 cm (Bt1 and Bt2 horizons).
Duripan - The zone from 58 to 102 cm (Bqkm horizon).
Lithic contact - The boundary at 102 cm to underlying hard, unweathered bedrock (R layer).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 28 to 58 cm (Bt1 and Bt2 horizons).

ADDITIONAL DATA: A similar pedon in the same family was sampled nearby for full characterization by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S82NV-021-005 (pedon #82P0627).

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National Cooperative Soil Survey
U.S.A.