LOCATION COLOSSEUM CA

Established Series
Rev: CAH/ET
04/2015

COLOSSEUM SERIES

The Colosseum series consists of very deep, somewhat excessively drained soils that formed in alluvium derived from limestone and dolomite. Colosseum soils are on fan aprons and drainageways. Slopes range from 2 to 15 percent. The mean annual precipitation is 150 millimeters and the mean annual temperature is about 18.5 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, carbonatic, thermic Typic Haplocalcids

TYPICAL PEDON: Colosseum fine sandy loam, on a 4 percent slope under desert rangeland at an elevation of 804 meters. When described the soil was dry throughout. (Colors are for dry soil unless otherwise noted). The surface is covered by 80 percent gravel and 5 percent cobbles.

A--0 to 3 centimeters (0 to 1 inch); pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; moderate thick platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots throughout; common very fine tubular and many very fine vesicular pores; 10 percent total gravel with 3 percent 2 to 5 millimeter limestone fragments and 7 percent 6 to 75 millimeter limestone fragments; violently effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (1 to 5 centimeters thick)

Bk--3 to 10 centimeters (1 to 4 inches); pale brown (10YR 6/3) gravelly loamy sand, brown (10YR 5/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine and medium roots throughout and many very fine roots throughout; common very fine tubular pores; 5 percent distinct white (10YR 8/1), calcium carbonate coats on bottom surfaces of rock fragments; 30 percent total gravel with 10 percent 2 to 5 millimeter limestone fragments and 20 percent 6 to 75 millimeter limestone fragments; violently effervescent (30 percent calcium carbonate equivalent); moderately alkaline (pH 8.2); clear wavy boundary. (7 to 51 centimeters thick)

Bkq--10 to 115 centimeters (4 to 45 inches); pale brown (10YR 6/3) extremely gravelly loamy sand, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots and common very fine roots throughout; 1 percent distinct silica on bottom surfaces of rock fragments; 40 percent distinct white (10YR 8/1), calcium carbonate coats on rock fragments; 70 percent total gravel with 20 percent 2 to 5 millimeter limestone fragments and 50 percent 5 to 75 millimeter limestone fragments; violently effervescent (40 percent calcium carbonate equivalent); moderately alkaline (pH 8.4); clear wavy boundary. (50 to 110 centimeters thick)

2Bkq--115 to 150 centimeters (45 to 59 inches); light yellowish brown (10YR 6/4) very gravelly fine sandy loam, yellowish brown (10YR 5/4) moist; massive parting to weak medium subangular blocky; soft, very friable, nonsticky and nonplastic; common very fine roots throughout; 1 percent distinct yellowish brown (10YR 5/4), silica on bottom surfaces of rock fragments; 4 percent distinct white (10YR 8/1), carbonate coats on bottom surfaces of rock fragments; 40 percent total gravel with 15 percent 2 to 5 millimeter limestone fragments and 25 percent 6 to 75 millimeter limestone fragments; violently effervescent (35 percent calcium carbonate equivalent); moderately alkaline (pH 8.4).

TYPE LOCATION: San Bernardino County, California; approximately 2 miles southeast of the edge of Mesquite Lake on Old Traction Road in the Bureau of Land Managements Clark Mountain Grazing Allotment; approximately 315 meters north and 565 meters east of the southwest corner of Section 23, T. 18 N., R. 13 E.; USGS Mesquite Lake, California 7.5 minute topographic quadrangle; 35 degrees, 29 minutes, 58 seconds N. latitude and 115 degrees, 32 minutes, 59 seconds W. longitude; UTM 11S 631260e, 3947899n; (DTM: 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 to September following summer convection storms. Has a Typic-Aridic moisture regime.

Soil temperature: 19 to 22 degrees C.
Depth to calcic horizon: 8 to 50 centimeters.
Organic matter: 0 to 0.5 percent.
Surface rock fragments: Ranges from 75 to 95 percent, dominated by gravel.

Control section-

Rock fragments: Averages 55 to 80 percent, ranges from 30 to 80 percent gravel and 0 to 7 percent cobbles.
Clay content: 2 to 8 percent.
Calcium carbonate equivalence of the less than 20 millimeter fraction: 40 to 60 percent.

A horizon:
Value: 6 or 7, dry; 4 or 5, moist.
Chroma: 3 or 4, dry or moist.
Texture of the fine earth fraction: Sand, fine sandy loam, loam or sandy loam.
Clay content: 2 to 15 percent.
Rock fragments: 10 to 60 percent, dominated by gravel.
Reaction: Slightly or moderately alkaline.

Bk or Bk1 horizon (s):
Value: 6 or 7, dry; 4 or 5, moist.
Chroma: 3 or 4, moist.
Texture of the fine earth fraction: Sand or loamy sand.
Clay content: 2 to 8 percent.
Rock fragments: Ranges from 30 to 70 percent, dominated by gravel.
Calcium carbonate equivalence of the fine earth: 10 to 30 percent.

Bkq or Bk2 horizon(s):
Value: 6 or 7, dry; 4 or 5, moist.
Chroma: 3 or 4, dry or moist.
Texture of the fine earth fraction: Sand, coarse sand and loamy sand
Clay content: 2 to 7 percent.
Rock fragments: 35 to 85 percent, dominated by gravel.
Calcium carbonate equivalence of the fine earth: 25 to 45 percent.
Silica: 0 to 2 percent visible on bottom of rock fragments.

2Bkq horizon(s):
Value: 5 or 6, dry; 4 or 5, moist.
Texture of the fine earth fraction: Sandy loam, fine sandy loam or loamy sand.
Clay content: 4 to 10 percent.
Rock fragments: 35 to 70 percent, dominated by gravel.
Calcium carbonate equivalence of the fine earth: 10 to 35 percent.
Silica: 1 to 2 percent visible coats on the bottom of rock fragments.
Reaction: Moderately or strongly alkaline.
Electrical Conductivity: 0 to 10 mmhos/cm.
Sodium adsorption ratio: 0 to 20.

COMPETING SERIES: There are no competing series at this time.

GEOGRAPHIC SETTING: Colosseum soils are on fan aprons and drainageways. Slopes range from 2 to 15 percent. These soils formed in alluvium derived from limestone and dolomite. Elevation is 795 to 1060 meters (2605 to 3475 feet). Mean annual precipitation 125 to 175 millimeters. The mean annual temperature is 17 to 20 degrees C. Frost free season is 280 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Weiser soils. Weiser soils are loamy-skeletal throughout the particle size control section and are on upper fan aprons and fan remnants.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; negligible to very low runoff; moderately rapid permeability. The soils are very rarely flooded on fan aprons and occasionally flooded on drainageways.

USE AND VEGETATION: This soil is used for rangeland and wildlife habitat. Vegetation is mainly creosotebush and white bursage on fan aprons and includes bush encelia, catclaw and Anderson wolfberry in drainageways.

DISTRIBUTION AND EXTENT: Southeastern California, U.S.A. MLRA 30. The soils are of moderate extent.

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

SERIES ESTABLISHED: San Bernardino County, Clark Mountain Grazing Allotment, part of the Mojave Desert, North East, California, 2007. The name is from the nearby Colosseum mine.

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

1. Ochric epipedon: 0 to 3 centimeters (0 to 1 inch). (A horizon)
2. Calcic horizon: 10 to 115 centimeters (4 to 45 inches). (Bkq horizon)
3. Particle-size control section: 25 to 100 centimeters (10 to 40 inches). (Part of the Bkq horizon)

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 6/2011. ET

National Cooperative Soil Survey
U.S.A.