LOCATION COUGARBUTTE CA

Tentative Series
REV: CAH/ET
04/2015

COUGARBUTTE SERIES

The Cougarbutte series consists of very shallow, somewhat excessively drained soils that formed in granitic residuum and alluvium. The Cougarbutte soils are on pediments and fan aprons over pediments. Slopes range from 2 to 15 percent. The mean annual precipitation is about 100 millimeters and the mean annual air temperature is about 19 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, thermic, shallow Typic Torriorthents

TYPICAL PEDON: Cougarbutte sandy loam, on a linear-convex, 4 percent slope at an elevation of 1018 meters. (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 15 percent gravel.

A -- 0 to 2 centimeters; very pale brown (10YR 7/4) sandy loam, yellowish brown (10YR 5/4) moist; moderate very thick platy structure; soft, very friable, slightly sticky and nonplastic; common very fine roots; common very fine and fine interstitial and common very fine and fine tubular pores; slightly effervescent; 5 percent gravel; moderately alkaline (pH 8.0); clear wavy boundary. (1 to 4 centimeters thick)

Bt -- 2 to 7 centimeters; strong brown (7.5YR 5/6) sandy loam, strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine interstitial pores; 5 percent faint bridging between sand grains; strongly effervescent; 10 percent gravel and 5 percent paragravel; moderately alkaline (pH 8.0); clear wavy boundary. (5 to 16 centimeters thick when C horizon is present)

Crtk -- 7 to 40 centimeters; weathered granitic bedrock with moderate to high excavation difficulty; common very fine and few fine roots in fractures; 10 percent distinct, strong brown (7.5YR 4/6) clay films on rock fragments; 1 percent distinct, light gray (10YR 7/2) calcium carbonate coats on rock fragments.

TYPE LOCATION: San Bernardino County, California; approximately 2.25 kilometers east of the Cougar Buttes; 50 meters west and south of the NE corner of section 32, T. 5 N., R. 2 E.; 34 degrees, 29 minutes and 9.3 seconds north latitude and 116 degrees, 47 minutes and 21.2 seconds west longitude; USGS Cougar Buttes 7.5 minute quadrangle; UTM 11S 519353e 3816049n (DTM: NAD-83).

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 October following convection storms. The soils have a Typic-Aridic moisture regime.

Soil temperature: 18 to 22 degrees C.

Depth to paralithic contact: 6 to 20 centimeters

Organic matter: 0 to 0.5 percent

Surface rock fragments: ranges from 15 to 50 percent; with 15 to 50 percent gravel (2-5mm), 0 to 1 percent cobbles.

Control section -
Rock fragments: 5 to 25 percent, dominantly gravel
Clay content: 8 to 18 percent

A horizon
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 3 or 4 dry, 3 to 6 moist
Texture: sand, loamy sand, sandy loam and loam
Clay content: 2 to 10 percent
Rock fragments: 3 to 10 percent, dominantly gravel
Effervescence: very slightly to violently effervescent
Reaction: slightly or moderately alkaline

C horizon (when present)
Value: 4 or 5, moist
Chroma: 3 or 4, dry or moist
Texture: sand, loamy sand, and sandy loam
Clay content: 2 to 10 percent
Rock fragments: 5 to 30 percent, dominantly gravel
Effervescence: slightly to strongly effervescent
Reaction: slightly to moderately alkaline

Bt or 2Bw horizon
Hue: 10YR or 7.5YR
Value: 3 to 8 dry, 4 to 7 moist
Chroma: 3 to 6, dry or moist
Clay content: 8 to 18 percent
Rock fragments: 1 to 10 percent, dominantly gravel
Effervescence: very slightly to violently effervescent
Reaction: neutral to moderately alkaline
Note: Bt either does not meet thickness or clay increase requirements to be an argillic horizon

COMPETING SERIES: These are the Randsburg (CA), Chinkle (NV), Cochora (CA), Calwash (NV) and Solis (TX) series. Randsburg soils do not receive summer precipitation and are 20 to 50 centimeters deep to soft bedrock. Chinkle, Cochora, Calwash and Solis soils are all underlain by sedimentary bedrock. Chinkle soils are more than 20 centimeters deep to soft bedrock while Cochora soils are 36 to 50 centimeters to bedrock and are dry throughout April to mid-December.

GEOGRAPHIC SETTING: Cougarbutte soils are on pediments and fan aprons over pediments. Slopes range from 2 to 15 percent. These soils formed in granitic residuum and alluvium. Elevations range from 850 to 1204 meters. The climate is arid with hot, dry summers and warm, moist winters. The mean annual precipitation is 75 to 125 millimeters; mean annual air temperature is 16 to 20 degrees C, and the frost-free season is 280 to 340 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ironped and Coyote soils. Ironped soils are on fan aprons over pediments and are sandy throughout the particle size control section. Coyote soils are on alluvial fans, are moderately deep, have a sandy particle size control section and have a calcic horizon with more than 20 percent durinodes.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very low to low runoff; rapid to moderately rapid permeability above the weathered bedrock.

USE AND VEGETATION: Cougarbutte soils are used for recreation and wildlife habitat. The present vegetation is mainly creosotebush and white bursage.

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

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

SERIES PROPOSED: San Bernardino County, California, Johnson Valley Off-Highway Vehicle Open Area Soil Survey, 2004. The name is from the nearby Cougar Buttes hills.

REMARKS: Diagnostic horizons and features recognized in the profile are:

1. Ochric epipedon: 0 to 2 centimeters (A horizon)
2. Particle size control section: 0 to 7 centimeters (A and Bt horizons)
3. Paralithic contact: the zone beginning at 7 centimeters (Crtk)

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 3/2005. ET

National Cooperative Soil Survey
U.S.A.