LOCATION CONTACTMINE             CA

Established Series
Rev: PRR/CAH/ET
04/2015

CONTACTMINE SERIES

The Contactmine series consists of moderately deep, well drained soils that formed in colluvium over residuum derived from granite and/or gneiss. The Contactmine soils are on hills and mountain. Slopes range from 4 to 75 percent. The mean annual precipitation is about 138 millimeters (5.5 inches) and the mean annual air temperature is about 18.5 degrees C (71 degrees F).

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Typic Haplargids

TYPICAL PEDON: Contactmine sandy loam, on a linear south-southwest facing, 31 percent slope under desert shrubs at an elevation of 1,419 meters. (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 25 percent fine gravel, 28 percent medium and coarse gravel, 10 percent cobbles, and 2 percent stones.

A1 -- 0 to 3 centimeters (0 to 1 inches); yellowish brown (10YR 5/4) sandy loam, dark brown (10YR 3/3) moist; moderate thin platy structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine vesicular pores; 4 percent fine gravel and 1 percent medium and coarse gravel; slightly alkaline (pH 7.6); abrupt wavy boundary. (3 to 15 centimeters thick)

A2 -- 3 to 12 centimeters (1 to 5 inches); yellowish brown (10YR 5/4) sandy loam, dark yellowish brown (10YR 3/4) moist; moderate fine granular structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots throughout; 8 percent fine gravel and 4 percent medium and coarse gravel; slightly alkaline (pH 7.4); clear wavy boundary. (0 to 10 centimeters thick)

Bt -- 12 to 23 centimeters (5 to 9 inches); yellowish brown (10YR 5/4) gravelly sandy clay loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; few fine and common very fine and medium roots throughout; common very fine dendritic tubular pores; 15 percent faint, yellowish brown (10YR 5/4) clay films on faces of peds; 4 percent fine gravel, 6 percent medium and coarse gravel and 5 percent cobbles; very slightly effervescent; slightly alkaline (pH 7.8); clear wavy boundary. (12 to 65 centimeters thick)

Btk1 -- 23 to 55 centimeters (9 to 22 inches); yellowish brown (10YR 5/4) cobbly loam, dark yellowish brown (10YR 3/6) moist; moderate medium subangular blocky structure; moderately hard, friable, moderately sticky and slightly plastic; common very fine roots throughout; few very fine dendritic tubular pores; 25 percent distinct, yellowish brown (10YR 5/4), clay films on faces of peds; 3 percent prominent, white (10YR 8/1), calcium carbonate coats on bottoms of rock fragments; 6 percent fine gravel, 2 percent medium and coarse gravel and 15 percent cobbles; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary.

Btk2--55 to 67 centimeters (22 to 26 inches); yellowish brown (10YR 5/4) extremely gravelly loam, dark yellowish brown (10YR 3/6) moist; weak coarse subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; 15 percent faint, yellowish brown (10YR 5/4), clay films on rock fragments; 3 percent prominent, white (10YR 8/1), calcium carbonate coats on bottoms of rock fragments; 25 percent fine gravel and 50 percent medium and coarse gravel; moderately alkaline (pH 8.0); clear wavy boundary. (Combined thickness of Btk horizons is 0 to 69 centimeters thick)

Cr--67 to 150 centimeters (26 to 60 inches); fractured, weakly cemented granite bedrock with fractures greater than 10 centimeters apart; moderate excavation difficulty.

TYPE LOCATION: San Bernardino County, California; approximately 1.3 kilometers north-northeast of the Desertqueen Mine parking area, approximately 80 meters south and 130 meters east of the northwest corner of sec. 5, T 2S., R 9E., San Bernardino Base and Meridian; 34 degrees, 2 minutes, 1 seconds north latitude and 116 degrees, 4 minutes, 8 seconds west longitude; USGS Queen Mountain 7.5 minute topographic quadrangle; UTM 585954e 3766261n (DTM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section: usually dry, moist in some parts for short periods during winter and early spring and for 10 to 20 days cumulative between July and September following summer convection storms. The soils have a typic-aridic soil moisture regime.

Soil temperature: 18.5 to 22 degrees C.

Surface rock fragments: ranges from 20 to 80 percent, with 5 to 50 percent fine gravel, 10 to 50 percent medium and coarse gravel, 10 to 20 percent cobbles, 3 to 10 percent stones, and 0 to 5 percent boulders.

Control section
Rock fragments: ranges from 10 to 75 percent, averaging 15 to 30 percent.
Clay content: averages 18 to 25 percent clay.
Organic matter: 0 to 0.5 percent.
Depth to argillic horizon: 10 to 25 centimeters.
Depth to paralithic contact: 50 to 100 centimeters.

A or A1 horizons
Value: 3 or 4 moist.
Chroma: 3 or 4 moist.
Clay content: 6 to 18 percent.
Rock fragments: 3 to 25 percent, gravel.
Reaction: neutral or slightly alkaline.
Note: some pedons are characterized by vesicular pores in this horizon.

A2 or Bw horizons (when present)
Value: 4 or 5, dry.
Chroma: 3 or 4, moist.
Clay content: 7 to 18 percent.
Rock fragments: 10 to 45 percent, 10 to 40 percent gravel and 0 to 5 percent cobbles.
Reaction: neutral to moderately alkaline.

Bt horizons
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 3 or 4 moist.
Chroma: 4 or 6, dry or moist.
Texture of the fine earth: sandy loam, loam, sandy clay
loam, or clay loam.
Clay content: ranging from 16 to 30 percent, averages 18 to 25
percent.
Rock fragments: ranges from 10 to 42 percent, averaging 15 to
30 percent with 2 to 35 percent gravel and 0 to 7 percent cobbles.

Btk horizon(s) (when present)
Chroma: 4 to 6, moist.
Texture of the fine earth: sandy loam, loam or clay loam.
Clay content: ranging from 18 to 28 percent, averages 18 to 25 percent.
Rock fragments: 15 to 75 percent, with 15 to 75 percent indurated gravel and 0 to 10 percent paragravel.
Reaction: slightly alkaline or moderately alkaline.

Cr horizon:
Cementation: very weakly to moderately cemented.

COMPETING SERIES: These are the Anway (CA), Avenal (AZ), Bryman (CA), Bucklebar (NM+AZ), Dutchflat (AZ), Garlock (CA), Hi Vista (CA), Milham (CA), Neuralia (CA), and Palomas (NM) soils. Anway, Avenal, Bryman, Bucklebar, Dutchflat, Garlock, Milham, Neuralia, and Palomas soils do not have a paralithic contact within 150 centimeters and are formed in alluvial parent material. In addition, Avenal, Bryman, Garlock, Hi Vista, Milham, and Neuralia soils are not moist in the moisture control section for 10 to 20 days following summer convection storms and Anway and Bucklebar soils are moist for more than 20 cumulative days during July through September. Bryman soils have Bt horizons with 5YR hues. Hi Vista soils have a lithic contact between 50 and 100 centimeters. Palomas soils have a hue of 2.5YR in the Bt horizons.

GEOGRAPHIC SETTING: Contactmine soils are on hills and mountains. Slopes range from 4 to 75 percent. These soils formed in colluvium over residuum derived from granite and/or gneiss. Elevation is 762 to 1440 meters (2500 to 4725 feet). The climate is arid with hot, dry summers and warm, moist winters. The mean annual precipitation is 100 to 175 millimeters and the mean annual air temperature is 17 to 20 degrees C. The frost free season is 270 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Desertqueen, Pinecity, Meccapass and Seanna soils. Pinecity, Desertqueen, Meccapass, and Seanna soils are found on similar landscape positions. Pinecity soils are sandy throughout and are very shallow or shallow to a paralithic contact. Desertqueen soils average less than 18 percent clay in the control section and are very shallow or shallow to a paralithic contact. Meccapass soils are found on hot, nearby south-facing slopes, have a cambic horizon that does not have enough increase in clay to be an argillic horizon, have more than 35 percent rock fragments in particle-size control section and less than 18 percent clay in the particle-size control section, while Seanna soils are very shallow and shallow to to a paralithic contact, do not have any diagnostic horizons, and have more than 35 percent rock fragments in the particle size control section.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high to very high runoff; moderately low saturated hydraulic conductivity above the bedrock and moderately high within the bedrock.

USE AND VEGETATION: These soils are used for recreation and wildlife habitat. Vegetation is blackbrush, burrobush, Nevada jointfir, and creosote bush.

DISTRIBUTION AND EXTENT: Southern Mojave Desert of southeastern California; MLRA 30. These soils are of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: San Bernardino County, California; Soil Survey of Joshua Tree National Park, California, 2012. The name is from Contact Mine located within the survey area.

REMARKS: Diagnostic horizons and features in this pedon include:

Ochric Epipedon - from a depth of 0 to 12 centimeters (0 to 5 inches) (A1 and A2 horizon)
Argillic Horizon - from a depth of 12 to 67 centimeters (5 to 27 inches) (Bt and Btk horizons)
Paralithic contact - the zone beginning at 67 centimeters (26 inches) (Cr horizon).
Particle size control section - from a depth of 12 to 62 centimeters (5 to 24 inches)(Bt, Btk1 and upper part of Btk2 horizons)

ADDITIONAL DATA: The NASIS User Pedon ID: 1249712329.

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 5/2012. ET

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National Cooperative Soil Survey
U.S.A.