LOCATION MESABASE                NV

Established Series
DJM/JVC/ET
11/2015

MESABASE SERIES

The Mesabase series consists of moderately deep, somewhat excessively drained soils that formed in alluvium derived dominantly from sandstone. Mesabase soils are on pediments. Slope ranges from 2 to 15 percent. The mean annual precipitation is about 6 inches and the mean annual temperature is about 72 degrees F.

TAXONOMIC CLASS: Sandy-skeletal, mixed, hyperthermic Typic Haplocalcids

TYPICAL PEDON: Mesabase extremely gravelly sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 65 percent pebbles and 5 percent cobbles.

A1--0 to 1 inch; light brown (7.5YR 6/3) extremely gravelly sandy loam, brown (7.5YR 4/3) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine interstitial pores; 65 percent pebbles and 5 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (1 to 3 inches thick)

A2--1 to 5 inches; light brown (7.5YR 6/3) very gravelly sandy loam, brown (7.5YR 5/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots; many very fine interstitial pores; 40 percent pebbles; violently effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (0 to 5 inches thick)

Bw--5 to 11 inches; light brown (7.5YR 6/3) extremely gravelly loamy sand, brown (7.5YR 5/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; 65 percent pebbles; strongly effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 7 inches thick)

Bk1--11 to 30 inches; light brown (7.5YR 6/3) very gravelly loamy sand, brown (7.5YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots; many very fine interstitial pores; few thin strata of very gravelly sandy loam; 15 percent medium and coarse calcium carbonate coats and pendants on the bottom of rock fragments; 45 percent pebbles; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary.

Bk2--30 to 38 inches; light brown (7.5YR 6/3) very gravelly loamy coarse sand, brown (7.5YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine interstitial pores; 20 percent medium and coarse calcium carbonate coats and pendants on the bottom of rock fragments; 50 percent pebbles; violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (Combined thickness of Bk horizons is 17 to 28 inches)

2Cr--38 inches; soft weathered sandstone.

TYPE LOCATION: Clark County, Nevada; in the Lake Mead National Recreation Area about 1 mile south of Pinto Ridge in the southwest end of Pinto Valley; about 560 feet south and 2480 feet east of the northwest corner of section 27, T.20s., R.66E.; USGS Boulder Canyon, NV 7.5 minute topographic quadrangle; 36 degrees 11 minutes 13 seconds north latitude and 114 degrees 36 minutes 26 seconds west longitude; UTM 11s, 0715164e, 4007337n; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture - Usually dry, moist in some part during winter and spring and intermittently moist in the upper part following summer convection storms; typic aridic soil moisture regime.

Soil temperature - 72 to 78 degrees F.

Depth to calcic horizon - 3 to 12 inches.

Depth to paralithic contact - 20 to 40 inches.

Reaction - Moderately alkaline or strongly alkaline.

Control section - Clay content: Averages 3 to 8 percent.

Rock fragments: Averages 35 to 60 percent, mainly gravel.

A horizons - Hue: 7.5YR through 2.5YR.

Value: 6 or 7 dry, 4 or 5 moist.

Chroma: 3 or 4 dry or moist.

Bw horizon (when present) - Hue: 7.5YR through 2.5YR.

Value: 4 or 5 moist.

Chroma: 3 through 5 moist.

Texture: Loamy coarse sand or loamy sand.

Clay content: 3 to 8 percent.

Rock fragments: 60 to 80 percent.

Bk horizons - Hue: 7.5YR through 2.5YR.

Value: 4 or 5 moist.

Texture: Loamy coarse sand or loamy sand; thin strata of very gravelly sandy loam are in some pedons.

Clay content: 5 to 8 percent.

Rock fragments: 35 to 60 percent.

Structure: Massive or subangular blocky.

Calcium carbonate: 15 to 25 percent medium to very coarse coats and pendants on the bottom of rock fragments.

Calcium carbonate equivalent in the fine earth fraction: 5 to 20 percent.

COMPETING SERIES: These are the Azsand, Riverbend, and Varwash series. All of these soils are very deep. Azsand soils have a calcic horizon at 12 to 14 inches.

GEOGRAPHIC SETTING: Mesabase soils are on pediments. These soils formed in alluvium derived dominantly from sandstone. Slope ranges from 2 to 15 percent. Elevations range from 1,400 to 2,800 feet. The climate is low latitude desert, with mild winters and very hot summers. Precipitation is greatest in the winter with lesser secondary peak in summer, typical of the Mojave Desert. The mean annual precipitation is 5 to 7 inches, the mean annual temperature is 69 to 75 degrees F., and the frost-free period is 300 to 360 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the competing Azsand soil which occurs on adjacent sand sheets.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very high runoff; rapid permeability.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly creosotebush, white bursage, and range ratany.

DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada; MLRA 30. These soils are not extensive.

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

SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County, Nevada, 1999. The name is coined.

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

Ochric epipedon - 0 to 7 inches (A1, A2 and part of the Bw horizons).

Calcic horizon - 11 to 38 inches (Bk1 and Bk2 horizons).

Paralithic contact - 38 inches (2Cr layer).

Particle-size control section - 10 to 38 inches (Bk1 and Bk2 and part of the Bw horizons).

Responsibility for this series was transferred from Davis to Phoenix 11/2015. The last revision to the series was 7/2006. ET

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National Cooperative Soil Survey
U.S.A.