LOCATION ZARK                    NV

Established Series
Rev. TSB-DWW-JVC-JBF
12/2019

ZARK SERIES

The Zark series consists of moderately deep, well drained soils that formed in residuum and colluvium derived from vitric tuff. Zark soils are on hills. Slopes are 2 to 15 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Ashy, glassy, mesic Vitritorrandic Haploxerolls

TYPICAL PEDON: Zark ashy loamy fine sand--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 13 cm; grayish brown (10YR 5/2) ashy loamy fine sand, very dark grayish brown (10YR 3/2) moist; weak thick platy structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine tubular pores; neutral (pH 7.1); abrupt smooth boundary. (8 to 15 cm thick)

A2--13 to 41 cm; grayish brown (10YR 5/2) ashy loamy fine sand, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine tubular pores; slightly alkaline (pH 7.5); clear wavy boundary. (23 to 30 cm thick)

Bq--41 to 74 cm; pale brown (10YR 6/3) ashy loamy fine sand, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots; common very fine tubular pores; 40 percent matrix is firm and brittle when moist; 5 percent hard, firm durinodes 1 to 5 cm in diameter; 5 percent gravel; moderately alkaline (pH 7.9); clear wavy boundary. (13 to 38 cm thick)

Bqk--74 to 89 cm; light brownish gray (2.5Y 6/2) gravelly ashy loamy fine sand, olive brown (2.5Y 4/4) moist; massive; hard, firm and brittle, nonsticky and nonplastic; few very fine roots; few very fine tubular pores; 20 percent gravel; secondary carbonates segregated as few fine strongly effervescent irregularly shaped filaments and masses; noneffervescent matrix; moderately alkaline (pH 8.2); abrupt wavy boundary. (8 to 18 cm thick)

Crk--89 cm; gray (10YR 6/1) soft vitric tuff; few masses of secondary calcium carbonate.

TYPE LOCATION: Elko County, Nevada; about 25 miles east of Jackpot and one mile east of Goose Creek; about 2,000 feet west and 150 feet south of the northeast corner of section 1, T. 46 N., R. 68 E.; USGS Fivemile Gulch 7.5 minute topographic quadrangle; latitude 41 degrees 54 minutes 51.7 seconds N and longitude 114 degrees 11 minutes 39.1 seconds W; WGS84 Decimal Degrees 41.9143056 latitude, -114.1941944longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry from mid-July through October; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 11 degrees C.
Mollic epipedon thickness: 25 to 46 cm.
Depth to horizons with firm, brittle matrix: 25 to 50 cm.
Depth to bedrock: 50 to 100 cm to a paralithic contact. The paralithic materials below the contact are vitric tuff.
Volcanic glass content: 30 to 95 percent in the coarse silt through fine sand fractions.
Reaction: Neutral or slightly alkaline.

Particle-size control section - Clay content: 5 to 15 percent.
Rock fragments: Averages 0 to 15 percent gravel. Lithology of fragments is tuff.

A1 horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 or 3 percent.

A2 horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: Ashy loamy fine sand or ashy loamy sand.
Organic matter content: 1 or 2 percent.

Bq horizon
Hue: 10YR or 2.5Y.
Chroma: 2 through 4, dry or moist.
Texture: Ashy loamy fine sand or ashy loamy sand.
Rock fragments: 0 to 10 percent gravel.
Reaction: Neutral to moderately alkaline.
Durinodes: 5 to 15 percent.

Bqk horizon
Hue: 10YR or 2.5Y.
Chroma: 2 through 4, dry or moist.
Rock fragments: 15 to 25 percent gravel.
Consistence: Hard dry, firm and brittle moist.
Identifiable secondary carbonates: Occurs in some pedons as masses and filaments.
Calcium carbonate equivalent: 0 to 1 percent.
Other features: Some pedons have up to 15 percent pararock fragments as paragravel or parachanners.

COMPETING SERIES: These are the Bitner, Brays, Chelan, Deskamp, Dryhollow, Emagert, Kester, Surprise, Weezweed, Winblow, Yellowhills, and Yotes series.

Bitner soils average 15 to 25 percent rock fragments in the particle-size control section, do not have horizons with identifiable secondary carbonates, and do not have horizons with firm consistence and a brittle manner of failure. Brays, Deskamp, Kester, and Winblow soils are moderately deep to lithic contacts. Chelan soils are deep to duripans. Dryhollow, Emagert, Surprise, Weezweed, Yellowhills, and Yotes soils are very deep.

GEOGRAPHIC SETTING: Zark soils are on hills. They formed in residuum and colluvium derived from vitric air-fall tuff. Slopes are 2 to 15 percent. Elevations range from 1,590 to 1,770 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 300 mm, the mean annual temperature is 7 to 10 degrees C, and the frost-free period is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ashart and Xerxes soils. Ashart soils have argillic horizons. Xerxes soils are shallow to bedrock.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high saturated hydraulic conductivity.

USE AND VEGETATION: Zark soils are used for rangeland and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, needleandthread, bluebunch wheatgrass, Indian ricegrass, and rabbitbrush.

DISTRIBUTION AND EXTENT: Northeastern Nevada. These soils are not extensive with about 8,400 acres of the series mapped to date. MLRA 25.

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

SERIES ESTABLISHED: Elko County (Northeast Part), Nevada, 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 41 cm (A1 and A2 horizons).
Durinodes - The zone from 41 to 74 cm (Bq horizon).
Identifiable secondary carbonates - The zone from 74 to 89 cm (Bqk horizon).
Paralithic contact - The boundary at 89 cm to underlying soft weathered bedrock (2Cr layer).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 25 to 89 cm (Bq and Bqk horizons and part of the A2 horizon).

The revision of February 2008 corrected the type location.

The revision of August 200 updated the taxonomic class from Vitrandic to Vitritorrandic subgroup to clarify that the series has an aridic moisture regime.

ADDITIONAL DATA: The typical pedon at the series type location has full characterization data by the Soil Survey Laboratory (SSL), Lincoln, NE, as user pedon id 83NV007058 (pedon # 84P0612).

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National Cooperative Soil Survey
U.S.A.