LOCATION AURUM                   NV

Established Series
Rev. CWL/JBF
11/2016

AURUM SERIES

The Aurum series consists of shallow to a duripan, well drained soils that formed in a mudflow deposit from welded tuff, limestone and quartzite. Aurum soils are on mountains. Slopes range from 4 to 15 percent. The mean annual precipitation is about 450 mm and the mean annual air temperature is about 5 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Haplic Durixerolls

TYPICAL PEDON: Aurum loam--rangeland. (Colors are for dry soil unless otherwise noted.) The surface is covered with approximately 25 percent gravel, 2 percent cobbles, and 2 percent stones mainly welded tuff, and 1 percent quartzite boulders.

A--0 to 12 cm; dark grayish brown (10YR 4/2), loam, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure parting to strong medium granular; soft, very friable, nonsticky and nonplastic; many very fine and few fine roots; common very fine and fine, few medium interstitial and tubular pores; 10 percent gravel; moderately alkaline (pH 8.2); clear smooth boundary. (10 to 25 cm thick)

ABt--12 to 23 cm; brown (10YR 5/3), clay loam, dark brown (10YR 3/3) moist; strong coarse subangular blocky structure parting to weak fine subangular blocky; slightly hard, firm, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; common very fine and few fine and medium interstitial and tubular pores; common faint clay films on faces of peds; 10 percent gravel; moderately alkaline (pH 8.3); clear smooth boundary. (0 to 13 cm thick)

Btk--23 to 36 cm; yellowish brown (10YR 5/4), gravelly clay loam, dark yellowish brown (10YR 3/4) moist; strong coarse angular blocky structure parting to moderate medium angular blocky; very hard, very firm, moderately sticky and moderately plastic; common very fine and few fine roots; common very fine, and few fine and medium tubular pores; common faint and few distinct clay films on faces of peds; common distinct (5 percent) secondary calcium carbonate concretions on bottom of rock fragments; 15 percent gravel; slightly effervescent; strongly alkaline (pH 8.5); gradual smooth boundary. (8 to 20 cm thick)

Bqkm1--36 to 92 cm; very pale brown (10YR 8/2), cemented material, very pale brown (10YR 7/3) moist; moderate thick platy structure; very hard, very firm; moderately cemented duripan by secondary silica and calcium carbonate; violently effervescent; strongly alkaline (pH 8.6); gradual smooth boundary.

Bqkm2--92 to 155 cm; very pale brown (10YR 8/2), cemented material, very pale brown (10YR 7/3) moist; moderate thick platy structure; extremely hard, slightly rigid; strongly cemented by secondary silica and calcium carbonate; violently effervescent; strongly alkaline (pH 8.6). (combined thickness of the Bqkm1 and Bqkm2 is 100 to 120 cm thick)

TYPE LOCATION: White Pine County, Nevada; about 0.5 mile south of Mud Spring and 100 yards east of the Siegel Creek Road and 50 feet north of jeep trail; section 34, T. 22 N., R. 65E; USGS Silver Canyon 7.5 minute quadrangle; latitude 39 degrees 45 minutes 56.3 seconds N and longitude 114 degrees 36 minutes 21.4 seconds W; WGS84 Decimal Degrees 39.7355000 latitude, -114.6047778 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry; moist in winter and spring, dry in all parts at least 45 consecutive days following the summer solstice (July and August); xeric soil moisture regime bordering aridic. Most of the snow received on the site blows off resulting in patchy snow cover from December through February.
Soil temperature: 5.5 to 7 degrees C.
Thickness of mollic epipedon: 18 to 25 cm.
Depth to argillic horizon: 10 to 25 cm.
Thickness of argillic horizon: 10 to 28 cm.
Depth to carbonates: 10 to 25 cm.

Particle-size control section - Clay content: 25 to 35 percent.
Rock fragments: 15 to 35 percent, mainly angular and subangular gravel. Lithology of the fragments is mainly welded tuff.

A horizon
Value: 4 or 5 dry, and 2 or 3 moist
Chroma: 2 or 3, dry and moist.
Organic matter: 2 to 4 percent.
Reaction: Slightly alkaline or moderately alkaline.
Mineralogy: 5 to 15 percent volcanic glass in the 0.02 to 2 mm fraction and averages 0.01 to 0.05 percent Al plus 1/2Fe, extracted by ammonium oxalate.

ABt horizon (when present)
Hue: 7.5 YR or 10 YR.
Value: 5 or 6 dry, and 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Loam or clay loam.
Clay: 20 to 30 percent.
Rock fragments: 10 to 35 percent, mainly as angular and subangular gravel.
Structure: Subangular blocky structure or angular blocky.
Effervescence: None to violently effervescent.
Soil reaction: Slightly alkaline or moderately alkaline.
Calcium carbonate equivalence: 0 to 5 percent.

Btk horizon
Value: 5 or 6 dry, and 3 or 4 moist.
Chroma: 3 or 4, dry and moist.
Texture: Loam or clay loam.
Clay: 25 to 35 percent.
Rock fragments: 15 to 35 percent, angular and subangular.
Structure: Subangular blocky, angular blocky, or platy.
Soil reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalence: 10 to 15 percent.

Bqkm horizons
Value: 7 or 8 dry, and 6 or 7 moist.
Chroma: 1 through 3 dry, and 2 through 4 moist.
Rock fragments: 20 to 40 percent, angular and subangular.
Cementation: Moderately or strongly cemented.
Soil reaction: Moderately alkaline or strongly alkaline.

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

GEOGRAPHIC SETTING: Aurum soils are on mudflows in mountains.
These soils formed in a mudflow deposit. Slopes range from 4 to 15 percent. Elevation ranges from 2,000 to 2,300 meters. The climate is dry-subhumid with cool moist winters and warm dry summers. The mean annual precipitation ranges from 400 to 500 mm.The mean annual air temperature ranges from 4 to 6 degrees C. The frost-free period ranges from about 40 to 70 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mattier, McIvey, and Siegel series.

Mattier soils are shallow to a lithic contact. McIvey soils do not have secondary calcium carbonate in the profile. Siegel soils have 35 to 45 percent clay and 35 to 50 percent rock fragments in the particle-size control section

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

USE AND VEGETATION: Aurum soils are used for livestock grazing, recreation, and wildlife habitat. The potential native vegetation is bluebunch wheatgrass, black sagebrush, and low sagebrush. This pedon is correlated to Ecological Site Description R028BY034NV, Mountain Ridge 12-14 P.Z.

DISTRIBUTION AND EXTENT: East Central Nevada, U.S.A. These soils are not extensive. The series concept and main acreage is in MLRA 28B.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: DAVIS, CALIFORNIA.

SERIES ESTABLISHED: White Pine County, Humboldt-Toiyabe National Forest, South Part, Nevada, 2013 (NV778). The name is from a local mining ghost town.

REMARKS: Diagnostic horizons and features recognized in the profile are:
Mollic epipedon - The zone from 0 to 23 cm (A1 and ABt horizons).
Argillic horizon - The zone from 12 to 36 cm (ABt and Btk horizons).
Duripan - The zone from 36 to 155 cm (Bqkm1 and Bqkm2 horizons).
Particle-size control section - The zone from 12 to 36 cm (ABt and Btk horizons).

ADDITIONAL DATA:
User Pedon ID: 09NV778065-CWL

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National Cooperative Soil Survey
U.S.A.