LOCATION THUNDERCLAP             CA

Established Series
Rev: SMR/LJL/CAH/ET
12/2015

THUNDERCLAP SERIES

The Thunderclap series consists of very deep, somewhat excessively drained soils formed in alluvium over residuum weathered from granitoid and gneissic rock. Thunderclap soils are on fan aprons over pediments. Slopes range from 4 to 8 percent. The mean annual precipitation is 200 millimeters (8 inches) and the mean annual air temperature is 15 degrees C (59 degrees F).

TAXONOMIC CLASS: Mixed, thermic Xeric Torripsamments

TYPICAL PEDON: Thunderclap sand on an east-facing, 8 percent slope at an elevation of 1,564 meters. (Colors are for dry soil unless otherwise stated.) The surface is covered by approximately 10 percent fine gravel.

A1 -- 0 to 6 centimeters (0 to 2 inches); brown (10YR 5/3) sand, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; 2 percent fine gravel; slightly alkaline (pH 7.7); clear smooth boundary.

A2 -- 6 to 28 centimeters (2 to 11 inches); brown (10YR 5/3) sand, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; few very fine tubular pores; 2 percent fine gravel; moderately alkaline (pH 8.0); clear smooth boundary. (Combined thickness of the A horizons is from 23 to 30 centimeters)

C1 -- 28 to 100 centimeters (11 to 37 inches); yellowish brown (10YR 5/4) sand, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; 2 percent fine gravel; moderately alkaline (pH 8.0); gradual smooth boundary.

C2 -- 100 to 160 centimeters (37 to 60 inches); yellowish brown (10YR 5/4) sand, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; moderately few very fine roots; 2 percent fine gravel; slightly alkaline (pH 7.6). (Combined thickness of the C horizons is greater than 100 centimeters)

Cr -- 160 to 200 centimeters (63 to 80 inches); soft granitoid bedrock with cracks greater than 10 centimeters apart; high excavation difficulty.

TYPE LOCATION: San Bernardino County, California; approximately 14.5 kilometers (9 miles) southwest of the Town of Yucca Valley; approximately 730 meters (2,400 feet) west and 355 meters (1,165 feet) south of the NE corner of sec. 2, T. 2 S., R. 6 E., San Bernardino Base and Meridian; USGS Joshua Tree South 7.5 minute topographic quadrangle; 34 degrees, 1 minute and 46 seconds north latitude and 116 degrees, 19 minutes and 34 seconds west longitude; UTM 11S 562203e 3765618n (DTM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section: usually dry from May 1 through November 30, and is moist in some or all parts the rest of the time. Aridic bordering on xeric soil moisture regime.

Soil temperature: 15 to 19 degrees C (59 to 66 degrees F).


Surface rock fragments: 10 to 34 percent, dominated by fine gravel.

Control section -
Rock fragments: 2 to 5 percent, dominantly fine gravel.
Organic matter: 0 to 1 percent.
Clay content: 1 to 4 percent.
Effervescence: noneffervescent throughout.
Depth to paralithic contact: 150 to 200 centimeters (60 to 80 inches).

A horizons
Value: 4 or 5 dry, and 3 or 4 moist.
Chroma: 3 or 4 dry, and 2 or 3 moist.
Texture of the fine earth fraction: sand or loamy sand.
Clay content: 2 to 4 percent.
Rock fragments: 2 to 5 percent, dominantly fine gravel.
Reaction: neutral to moderately alkaline.

C horizons
Chroma: 3 or 4, moist.
Texture of the fine earth fraction: sand or loamy sand.
Clay content: 1 to 4 percent.
Rock fragments: 2 to 17 percent, dominantly fine gravel; 2 to 5 percent in the upper part and 2 to 17 percent in the lower part.
Reaction: neutral to moderately alkaline.

COMPETING SERIES: These are the Cinco (CA), Inyo (CA), Pilotwell (CA), Wheelridge (CA) and Whitewolf (CA) series. Cinco soils have effervescence in the A horizon and average 15 to 35 percent fine gravel in the control section. Pilotwell soils are moderately deep (50 to 100 centimeters) to a paralithic contact. Inyo, Wheelridge and Whitewolf soils do not have bedrock within two meters. In addition, Inyo soils are formed in mixed alluvium and eolian deposits and Wheelridge soils have strongly or violently effervescent Bk horizons.

GEOGRAPHIC SETTING: Thunderclap soils are on fan aprons over pediment. Slopes range from 4 to 8 percent. These soils formed in alluvium over residuum weathered from granitoid and gneissic rock. Elevation ranges from 1,370 to 1,750 meters (4,495 to 5,740 feet). The climate is arid bordering on xeric with warm, dry summers, and cool, moist winters. The mean annual precipitation is 175 to 250 millimeters (7 to 10 inches) and the mean annual air temperature is 13 to 17 degrees C (55 to 63 degrees F). The frost-free season is 210 to 270 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Smithcanyon and Pinecity soils. Smithcanyon and Pinecity soils are on pediments and low hills and are shallow to bedrock. In addition, Pinecity soils are found on drier slopes and have a typic-aridic soil moisture regime.

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

USE AND VEGETATION: Thunderclap soils are used for recreation and wildlife habitat. The native vegetation is blackbrush, California juniper, Muller oak, Desert bitterbrush and Desert almond.

DISTRIBUTION AND EXTENT: Southern Mojave Desert of southeastern California. MLRA 30. The series is 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 coined.

REMARKS: Diagnostic horizons and features in this pedon include:

Ochric epipedon - from a depth of 0 to 18 centimeters (A1 and upper part of A2 horizon).
Paralithic contact - the zone beginning at 160 centimeters (Cr horizon).
Particle-size control section - from a depth of 25 to 100 centimeters
(part of the A2 and the C1 horizons).

ADDITIONAL DATA: NASIS User Pedon ID: 1249806933.

Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 5/2012. ET

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National Cooperative Soil Survey
U.S.A.