LOCATION TABLETOP CA

Established Series
SMR/LJL/RVP/MEB
02/2025

TABLETOP SERIES

The Tabletop series consists of very shallow and shallow, well drained soils formed in calcareous eolian deposits over colluvium and/or residuum weathered from basalt and andesite. These soils are on lava flows. Slope ranges from 4 to 15 percent. The mean annual precipitation is about 150 mm, and the mean annual temperature is 18 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Argic Petrocalcids

TYPICAL PEDON: Tabletop fine sandy loam, on a south-facing, 4 percent slope under rangeland at an elevation of 1,257 meters. (Colors are for dry soil unless otherwise stated.) The surface is covered by approximately 5 percent fine gravel, 12 percent medium and coarse gravel, 15 percent cobbles, 1 percent stones, and 12 percent calcium carbonate nodule gravel.

A--0 to 3 cm (0 to 1 inches); brown (10YR 5/3) fine sandy loam, brown (7.5YR 4/3), moist; moderate thick platy structure; soft, very friable, slightly sticky and moderately plastic; many very fine roots throughout; common very fine irregular pores; 2 percent medium faint platy strongly coherent cemented white (10YR 8/1), dry, carbonate nodules with sharp boundaries at top of horizon; 5 percent fine gravel, 5 percent medium and coarse gravel, 2 percent cobbles; violent effervescence (8 percent calcium carbonate equivalent of the fine earth); moderately alkaline (pH 8.3); clear smooth boundary. (3 to 6 cm thick)

Bw--3 to 17 cm (1 to 7 inches); brown (7.5YR 5/3) fine sandy loam, brown (7.5YR 4/4), moist; moderate coarse subangular blocky structure; soft, very friable, moderately sticky and moderately plastic; common very fine roots throughout; common very fine irregular pores; 3 percent fine gravel, 2 percent medium and coarse gravel, 2 percent cobbles; violent effervescence (9 percent calcium carbonate equivalent of the fine earth); moderately alkaline (pH 8.3); gradual smooth boundary. (0 to 15 cm thick)

Btk--17 to 36 cm (7 to 14 inches); brown (7.5YR 5/4) gravelly loam, brown (7.5YR 4/4), moist; weak medium subangular blocky structure; slightly hard, very friable, moderately sticky and very plastic; common very fine roots throughout; common very fine irregular pores; 15 percent faint brown (7.5YR 5/4), dry, clay bridges between sand grains and 20 percent distinct very pale brown (10YR 8/2), dry, carbonate coats on bottom surfaces of rock fragments; 5 percent fine gravel, 10 percent medium and coarse gravel, 5 percent cobbles, 2 percent stones; violent effervescence (10 percent calcium carbonate equivalent of the fine earth); moderately alkaline (pH 8.2); abrupt wavy boundary. (15 to 30 cm thick)

Bkkm--36 to 69 cm (14 to 27 inches); very pale brown (10YR 8/2) cemented gravelly loam, pale brown (10YR 6/3), moist; strong very fine platy structure; extremely hard, extremely firm, moderately coherent by carbonates, slightly sticky and slightly plastic; few very fine roots in cracks; 100 percent prominent white (10YR 8/1), dry, carbonate coats on rock fragments; 15 percent coarse faint platy strongly coherent cemented white (10YR 8/1), dry, carbonate nodules with sharp boundaries at top of horizon; 5 percent fine gravel, 7 percent medium and coarse gravel, 5 percent cobbles, 2 percent stones; violent effervescence (40 percent calcium carbonate equivalent of the fine earth); strongly alkaline (pH 8.5); abrupt smooth boundary. (20 to 40 cm thick)

Rk--69 cm (27 inches); indurated basalt bedrock (fractures 10 to <45 cm apart); 100 percent prominent white (10YR 8/1), dry, carbonate coats on bedrock.

TYPE LOCATION: San Bernardino County, California; approximately 19 miles southeast of the Town of Nipton, California; approximately 2300 feet south and 125 feet west of the northeast corner of section 28, T. 14 N., R. 18 E., San Bernardino Base and Meridian; USGS Hart Peak, California 7.5 minute topographic quadrangle; 35 degrees, 16 minutes, 0.1 seconds north latitude and 115 degrees, 2 minutes, 1.2 seconds west longitude; UTM 11S 678858e 3904392n (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 and September following summer convection storms; typic aridic moisture regime.

Soil temperature: 19 to 22 degrees C (66 to 72 degrees F).
Surface rock fragments: 15 to 75 percent, dominated by gravel.

Control section
Rock fragments: averages 5 to 25 percent.
Clay content: averages 15 to 25 percent.
Organic matter: 0 to 0.25 percent.
Depth to argillic horizon: 3 to 18 cm (1 to 7 inches).
Depth to petrocalcic horizon: 25 to 50 cm (10 to 20 inches).
Depth to lithic contact: 50 to 75 cm (20 to 30 inches).

A horizon
Hue: 10YR or 7.5YR moist.
Value: 4 to 6 dry, 3 or 4 moist.
Clay content: 7 to 15 percent.
Rock fragments: 5 to 15 percent.
Effervescence: strongly to violently effervescent.
Calcium carbonate equivalent: 5 to 10 percent.
Reaction: slightly alkaline or moderately alkaline.

Bw, Bk or Bt horizons (when present)
Hue: 10YR or 7.5YR, dry and moist.
Value: 5 or 6 dry.
Chroma: 3 or 4 moist.
Texture of the fine earth fraction: fine sandy loam or loam.
Clay content: 10 to 18 percent.
Rock fragments: 5 to 35 percent, dominantly gravel.
Effervescence: strongly to violently effervescent.
Calcium carbonate equivalence: 5 to 15 percent.

Btk horizon
Hue: 10YR or 7.5YR, dry and moist.
Chroma: 3 or 4 dry.
Clay content: 15 to 25 percent.
Rock fragments: 5 to 25 percent, dominantly gravel.
Calcium carbonate equivalence: 5 to 15 percent.

Bkkq or Bkkqm horizon
Value: 6 or 7 moist.
Chroma: 1 or 2 dry, 2 to 4 moist.
Texture of the fine earth fraction: sandy loam or loam.
Clay content: 8 to 15 percent.
Rock fragments: 5 to 35 percent, dominantly gravel.
Calcium carbonate equivalent: 35 to 55 percent.
Cementation: 60 to 90 percent, weakly to strongly cemented.
Reaction: moderately alkaline to strongly alkaline.

COMPETING SERIES: These are the Cruces and Mormount series. These soils do not have a lithic contact below the petrocalcic horizon. In addition, Cruces soils are moist for greater than 20 days during the summer, and have hues of 2.5YR and 5YR in the argillic horizon. Mormount soils have an indurated petrocalcic, and formed in alluvium from limestone.

GEOGRAPHIC SETTING: Tabletop soils are on lava flows. Slope ranges from 4 to 15 percent. These soils formed in calcareous eolian deposits over colluvium and/or residuum weathered from basalt and andesite. Elevation ranges from 1030 to 1500 meters. The mean annual precipitation is 125 to 175 mm. The mean annual air temperature is 17 to 20 degrees C. The frost-free period is 270 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Newera and Highland soils. Newera soils occur on very steep slopes, have greater than 35 percent rock fragments within the particle size control section, do not have a petrocalcic horizon, and have a lithic contact within 36 cm. Highland soils occur on steep hillslopes, have greater than 35 percent rock fragments within the particle size control section, do not have a petrocalcic horizon, and have a lithic contact within 50 to 100 cm.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high runoff; moderately high saturated hydraulic conductivity in the upper part and moderately low in the lower part.

USE AND VEGETATION: Tabletop soils are used for recreation and wildlife habitat. The native vegetation is big galleta, creosote bush, Mojave yucca, and bush muly.

DISTRIBUTION AND EXTENT: Mojave Basin and Range of California, U.S.A.; MLRA 30. The series is of small extent.

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

SERIES PROPOSED: San Bernardino County, California, Soil Survey of Mojave National Preserve Area, California, 2022. The name is coined.

REMARKS: Diagnostic horizons and features in this pedon include:

Ochric epipedon - the zone from 0 to 17 cm.
Argillic horizon - the zone from 17 to 36 cm.
Petrocalcic horizon - the zone from 36 to 69 cm.
Lithic contact - the zone beginning at 69 cm.
Particle size control section - the zone from 0 to 36 cm.

ADDITIONAL DATA: NASIS User/Pedon Site ID: 2013CA0710060.

National Cooperative Soil Survey
U.S.A.