LOCATION TAN                ID
Tentative Series
Rev. BJD/TDT
03/2001

TAN SERIES


The Tan series consists of very deep, well-drained soils formed in alluvium from limestone. These soils are on outwash fans and fan terraces. Slopes are 0 to 2 percent. Permeability is rapid to very rapid. The average annual precipitation is about 9 inches and the average annual temperature is about 43 degrees F .

TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Durinodic Haplocalcids

TYPICAL PEDON: Tan gravelly loam, rangeland-on a flat outwash terrace at an elevation of 5,100 feet. (Colors are for dry soil unless otherwise stated.)

A--0 to 3 inches; light brownish gray (10YR 6/2) gravelly loam, dark grayish brown (10YR 4/2) moist; moderate fine platy structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine and fine roots; common very fine and fine interstitial pores; disseminated lime; 15 percent pebbles and 2 percent cobbles; slightly effervescent; slightly alkaline (7.8); clear smooth boundary. (1 to 4 inches thick)

Bw--3 to 11 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and slightly plastic; many very fine and fine and common medium roots; common very fine interstitial pores; disseminated lime; 20 percent pebbles and 5 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (7 to 12 inches thick)

Bkq1--11 to 20 inches; light gray (10YR 7/2) extremely gravelly sandy loam, grayish brown (10YR 5/2) moist; weak fine and very fine subangular blocky structure; hard, firm, nonsticky and slightly plastic; many very fine and fine and few medium roots; few very fine interstitial pores; weak discontinuous cementation; 2 to 3 mm thick lime and silica coats on undersides of rock fragments; 55 percent pebbles and 10 percent cobbles; violently effervescent; moderately alkaline (pH 8.1); clear wavy boundary. (7 to 12 inches thick)

Bkq2--20 to 29 inches; light gray (10YR 7/2) extremely gravelly loamy sand, grayish brown (10YR 5/2) moist; single grain; loose, nonsticky and nonplastic; common very fine and fine and few medium roots; few very fine interstitial pores; 1 to 2 mm thick lime and silica coats on undersides of rock fragments; 60 percent pebbles and 10 percent cobbles; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary.

Bkq3--29 to 49 inches; light gray (10YR 7/2) extremely gravelly loamy sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; few very fine interstitial pores; 1 to 2 mm thick lime and silica coats on undersides of rock fragments; 60 percent pebbles and 15 percent cobbles; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary.

Bkq4--49 to 60 inches; light gray (10YR 7/2) extremely gravelly loamy sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; 1 to 2 mm thick lime and silica coats on undersides of rock fragments; 60 percent pebbles and 15 percent cobbles; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary.

TYPE LOCATION: Butte County, Idaho; about 4 miles north of the INEEL TAN facility, 1,900 feet east and 1,200 feet north of the southwest corner of section 13, T. 7 N., R. 31 E. (Latitude 43 degrees 55 minutes 55 seconds N., Longitude 112 degrees 42 minutes 25 seconds W.)

RANGE IN CHARACTERISTICS:

Soil moisture control section- Dry in all parts for over three-fourths of the time when the soil temperature is above 5 degrees C.
Average annual soil temperature - 42 to 47 degrees F.
Depth to hard, firm, brittle layer - 8 to 14 inches

Particle-size control section
Clay content -5 to 10 percent
Rock fragments -55 to 75 percent

A horizon
Chroma - 2 or 3 dry or moist
Textures - gravelly loam
Clay content - 15 to 18 percent
Rock fragments - 15 to 20 pebbles, 0 to 5 percent cobbles
Calcium carbonate equivalent -10 to 20 percent
Reaction- slightly to moderately alkaline

Bw horizon
Chroma - 2 or 3 dry or moist
Textures - gravelly loam
Clay content - 15 to 18 percent
Rock fragments - 15 to 20 percent pebbles, 0 to 5 percent cobbles
Calcium carbonate equivalent -.10 to 20 percent
Reaction- slightly to moderately alkaline

Bkq1 horizon
Value - 6 or 7 dry, 3 or 4 moist
Chroma - 2 or 3 dry or moist
Textures - extremely gravelly sandy loam
Clay content - 5 to 10 percent
Rock fragments - 50 to 65 percent pebbles, 5 to 15 percent cobbles
Calcium carbonate equivalent - 20 to 35 percent
Reaction - moderately alkaline

Bkq2, Bkq3, and Bkq4 horizons
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 or 3 dry or moist
Textures - extremely loamy sand
Clay content - 3 to 8 percent
Rock fragments - 55 to 65 percent pebbles, 5 to 15 percent cobbles
Calcium carbonate equivalent - 20 to 30 percent
Reaction - moderately alkaline

COMPETING SERIES: There are no competing series

GEOGRAPHIC SETTING:
Landform: outwash terrace and fan terrace
Elevation: 5,000 to 5,200 feet
Slope: 0 to 2 percent
Parent material: alluvium from limestone
Climate: long, cool winters; dry, warm summers
Average annual precipitation: 7 to 10 inches
Average annual temperature: 40 to 44 degrees F.
Frost-free season: 70 to 120 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fallert, Paint, and Simeroi soils. Fallert soils are on fan terraces and have carbonatic mineralogy and an aridic moisture regime bordering on xeric. Paint soils are on fan terraces and alluvial fans, have carbonatic mineralogy, a loamy-skeletal control section, and a duripan at a shallow depth. Simeroi soils are on fan terraces and alluvial fans, have carbonatic mineralogy, a loamy-skeletal control section, and an aridic moisture regime bordering xeric.

DRAINAGE AND PERMEABILITY: Well drained, rapid to very rapid permeability.

USE AND VEGETATION: These soils are mainly used for rangeland and wildlife habitat. The dominant native vegetation is Wyoming big sagebrush, shadscale saltbrush, Indian ricegrass, needleandthread, Sandberg bluegrass, winterfat, and prickly pear cactus.

DISTRIBUTION AND EXTENT: East-central Idaho. These soils are of small extent.

MLRA OFFICE RESPONSIBLE: Portland, Oregon

SERIES PROPOSED: Clark County, Idaho, 2000. The name is from the Idaho National Environmental and Engineering Laboratory facility.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Calcic horizon - the zone from 11 to 60 inches. (Bkq horizons)
Depth to hard, firm, brittle layer- 8 to 14 inches


National Cooperative Soil Survey
U.S.A.