LOCATION OROFINO CA

Established Series
REV:EEM/CAH/LJL/SMR
02/2025

OROFINO SERIES

The Orofino series consists of very shallow and shallow to bedrock, somewhat excessively drained soils that formed in eolian sands over residuum and colluvium derived from limestone and dolomite. Orofino soils are on hills. Slopes range from 30 to 75 percent. The mean annual precipitation is about 100 mm, and the mean annual temperature is about 22 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, mixed, hyperthermic Lithic Torriorthents

TYPICAL PEDON: Orofino extremely gravelly fine sand, on an east-northeast facing, convex-concave 45 percent slope under desert shrubs at an elevation of 396 meters (1300 feet). (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 5 percent fine gravel, 42 percent medium and coarse gravel, 25 percent cobbles, 10 percent stones and 2 percent boulders.

A--0 to 5 cm (0 to 2 inches); pale brown (10YR 6/3) extremely gravelly fine sand, brown (10YR 4/3) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots throughout; common very fine irregular and common fine tubular pores; 15 percent distinct, white (10YR 8/1), calcium carbonate coats on rock fragments; 5 percent fine gravel, 45 percent medium and coarse gravel, 15 percent cobbles and 10 percent stones; very slightly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (3 to 7 cm thick)

Ck1--5 to 22 cm (2 to 9 inches); pale brown (10YR 6/3) very gravelly loamy fine sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; common very fine, fine and medium roots throughout; common fine irregular pores; 30 percent distinct white (10YR 8/1) calcium carbonate coats on rock fragments; 10 percent fine gravel, 40 percent medium and coarse gravel, 5 percent cobbles and 2 percent stones; strongly effervescent; strongly alkaline (pH 8.7); clear wavy boundary. (7 to 30 cm thick)

Ck2--22 to 32 cm (9 to 13 inches); pale brown (10YR 6/3) extremely gravelly fine sandy loam, brown (10YR 4/3) moist; massive; loose, nonsticky and nonplastic; common very fine roots throughout; 100 percent prominent, very pale brown (10YR 8/2), calcium carbonate coats on the top of rock fragments; 2 percent medium, distinct, very pale brown (10YR 8/2), very strongly-cemented, platy, calcium carbonate nodules on the bottom of rock fragments; 10 percent fine gravel, 45 percent medium and coarse gravel and 5 percent cobbles; violently effervescent; strongly alkaline (pH 8.7); abrupt wavy boundary. (0 to 15 cm thick)

Rk--32 cm (13 inches); unweathered limestone bedrock; 90 percent distinct, white (10YR 8/1) calcium carbonate coats on the bedrock.

TYPE LOCATION: San Bernardino, California; about 7 miles southeast of Baker, California, in the east end of the Little Cowhole Mountains; 2170 feet east and 460 feet north of the southwest corner of section 26, T. 13 N., R. 9 E., San Bernardino Base Meridian; 35 degrees, 10 minutes, 39.3 seconds latitude and 115 degrees, 59 minutes and 52.5 seconds longitude; USGS Seventeenmile Point, CA 7.5 minute topographic quadrangle; UTM 0591246e 3893197n (DATUM: NAD83).

RANGE IN CHARACTERISTICS:
Soil moisture: usually dry, moist in some part for short periods during winter and early spring and for 10 to 20 days cumulative between July and September following summer convection storms; typic aridic moisture regime.

Soil temperature: 22 to 25 degrees C (72 to 77 degrees F).
Depth to lithic contact: 10 to 36 cm (4 to 14 inches).
Organic matter: 0 to 0.4 percent.

Control section
Rock fragments: 35 to 80 percent
Clay content: Averages 0 to 8 percent

A horizon
Value: 6 or 7 dry, 3 to 5 moist.
Chroma: 2 or 3 moist.
Clay content: 0 to 6 percent.
Rock fragments: 60 to 80 percent gravel with 5 to 20 percent cobbles and 1 to 12 percent stones and 0 to 3 percent boulders.
Effervescence: noneffervescent to strongly effervescent.
Reaction: moderately to strongly alkaline.

Ck1 or Ck horizon(s)
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4 dry
Texture of the fine earth fraction: fine sand, loamy sand, or loamy fine sand
Clay content: 0 to 8 percent
Rock fragments: 35 to 80 percent gravel with 0 to 15 percent cobbles and 0 to 10 percent stones
Effervescence: very slightly to violently effervescent
Reaction: moderately or strongly alkaline
Calcium carbonate equivalence of the fine earth fraction: 0 to 5 percent

Ck2 horizon (when present)
Texture of the fine earth fraction: loamy fine sand or fine sandy loam
Clay content: 2 to 10 percent
Rock fragments: 50 to 80 percent gravel with 0 to 15 percent cobbles and 0 to 5 percent stones
Effervescence: very slightly to violently effervescent
Reaction: moderately or strongly alkaline
Calcium carbonate equivalence of the fine earth fraction: 0 to 5 percent
Calcium carbonate nodules: 0 to 4 percent as pendants

COMPETING SERIES: This is the Bolero (CA) series. Bolero soils have a lithic contact at 36 to 50 cm and are formed from granitic or gneissic bedrock.

GEOGRAPHIC SETTING: Orofino soils are on hills. Slopes range from 30 to 75 percent. These soils formed in eolian sands over residuum and colluvium derived from limestone and dolomite. Elevations range from 350 to 985 meters. The climate is arid with hot, dry summers and warm, moist winters. The mean annual precipitation is 75 to 125 mm (3 to 5 inches); mean annual air temperature is 20 to 23 degrees C (68 to 73.4 degrees F). The frost-free season is 300 to 340 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Iceberg and Carrizo soils. Iceberg soils are on adjacent backslopes. Carrizo soils are in nearby drainageways. Iceberg soils have a lithic contact at 36 to 50 cm and a particle-size control section that is loamy-skeletal with carbonatic mineralogy. Carrizo soils receive flooding, do not have a lithic contact and are greater than 150 cm deep.

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

USE AND VEGETATION: Orofino soils are used for recreation and wildlife habitat. Native vegetation is burrobush, white brittlebush and creosote bush.

DISTRIBUTION AND EXTENT: Mojave Desert of southeastern California, U.S.A., MLRA 30. The series is of small extent.

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

SERIES PROPOSED: San Bernardino, California; Soil Survey of the Mojave National Preserve Area, California, 2013. The name is coined from the Orofino Mine located 9 kilometers (5.5 miles) east-northeast of the typical pedon.

REMARKS: Diagnostic horizons and features recognized in this pedon include:

Ochric epipedon - from a depth of 0 to 5 cm (0 to 2 inches) (A horizon).
Particle-size control section - from a depth of 0 to 32 cm (0 to 13 inches) (A, Ck1 and Ck2 horizons).
Lithic contact - the zone beginning at 32 cm (13 inches) (Rk horizon).

ADDITIONAL DATA: NASIS User Pedon ID: 2013CA0711017

National Cooperative Soil Survey
U.S.A.