LOCATION ESTABAN NMTentative Series
TAXONOMIC CLASS: Fragmental, mixed, frigid Typic Haplustepts
TYPICAL PEDON: Estaban extremely gravelly loam--on a backslope of a canyon sloping 65 percent to the north-northeast at 8,758 feet elevation--forestland. (Colors are for dry soil unless otherwise noted. When described on September 6, 2000, the soil was dry to 12 inches and slightly moist from 12 to 84 inches.) Surface is covered with 1 percent stones.
Oi--0 to 1 inch; slightly decomposed needles, twigs, and cones; abrupt smooth boundary. (1 to 4 inches thick.)
A--1 to 4 inches; brown (10YR 5/3) extremely gravelly loam, brown (10YR 4/3) moist; weak fine subangular blocky structure parting to weak fine granular; soft, very friable, slightly sticky and nonplastic; few coarse, common medium, few fine, and common very fine roots; few fine and few very fine irregularly shaped pores; 55 percent gravel, 10 percent cobbles, and 1 percent stones; neutral (pH 7.2); clear smooth boundary. (3 to 6 inches thick.)
AB--4 to 14 inches; light brownish gray (10YR 6/2) extremely gravelly loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few coarse, common medium, common fine, and common very fine roots; common fine tubular pores; 60 percent gravel and 5 percent cobbles; neutral (pH 6.8); gradual wavy boundary. (5 to 12 inches thick.)
Bw--14 to 21 inches; light brownish gray (10YR 6/2) extremely gravelly sandy loam, dark grayish brown (10YR 4/2) moist; single grain; loose, slightly sticky and nonplastic; few coarse, common medium, common fine, and few very fine roots; common fine and few very fine tubular pores; 70 percent gravel, 10 percent cobbles, and 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (6 to 9 inches thick.)
C--21 to 84 inches; cobbles; fine earth is light gray (10YR 7/2) sandy loam, grayish brown (10YR 5/2) moist; single grain; loose, slightly sticky and nonplastic; few coarse, few medium, common fine, and common very fine roots; many very coarse irregularly shaped voids; 35 percent gravel, 50 percent cobbles, 10 percent stones, and 1 percent boulders; rock fragments are angular dacite fragments separated by voids lacking fine earth in some parts; slightly acid (pH 6.4).
TYPE LOCATION: Bandelier National Monument, Los Alamos County, New Mexico; about 8 miles southwest of Los Alamos; USGS Bland 7.5 minute topographic quadrangle; Latitude 35 degrees 48 minutes 47.31 seconds North and Longitude 106 degrees 24 minutes 45.06 seconds West, NAD 27.
RANGE IN CHARACTERISTICS: (Depths given are measured from the mineral soil surface)
Soil moisture - The soil moisture control section (SMCS) is moist in all parts from January to May and intermittently moist in some part from June to December. The SMCS is dry in all parts less than 40 percent of the time and dry in some or all parts more than 105 cumulative days when the soil temperature at 20 inches (50 cm) is above 41 degrees F. The soil moisture regime is typic ustic.
Average annual soil temperature: 43 to 45 degrees F
Thickness of ochric epipedon: 3 to 6 inches
Depth to fragmental material: 14 to 25 inches
Lithology of rock fragments: Dacite and latite
Particle size control section weighted averages:
Silicate clay content: 8 to 18 percent
Sand content: 40 to 55 percent
Fine sand or coarser content: 30 to 45 percent
Rock fragment content: 90 to 95 percent
A horizon
Value- 4 to 6 dry, 2 to 4 moist
Chroma- 1 to 3 dry or moist
Clay content: 8 to 18 percent
Base saturation: 70 to 95 percent
Rock fragments: total range is 60 to 80 percent
50 to 60 percent gravel
5 to 20 percent cobbles
0 to 2 percent stones
AB horizons
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 1 to 4, dry or moist
Texture: extremely gravelly loam, extremely gravelly sandy loam, extremely cobbly loam
Clay content: 8 to 18 percent
Base saturation: 65 to 90 percent
Rock fragments: total range is 60 to 80 percent
45 to 60 percent gravel
15 to 30 percent cobbles
0 to 5 percent stones
Other features: This horizon does not have mollic colors.
Bw horizons
Value: 5 to 8 dry, 4 to 6 moist
Chroma: 1 to 3 dry, 2 or 3 moist
Texture: extremely gravelly sandy loam, extremely gravelly loam, extremely cobbly loam
Clay content: 8 to 18 percent
Base saturation: 60 to 85 percent
Rock fragments: total range is 60 to 90 percent
55 to 70 percent gravel
15 to 30 percent cobbles
0 to 5 percent stones
C horizons
Value: 6 to 8 dry, 5 or 6 moist
Chroma: 1 to 4 dry, 2 to 4 moist
Texture: gravel, cobbles
Clay content: 8 to 18 percent (in fine earth
Base saturation: 60 to 85 percent (in fine earth)
Rock fragments: total range is 90 to 95 percent
35 to 65 percent gravel
25 to 50 percent cobbles
0 to 5 percent stones
0 to 5 percent boulders
COMPETING SERIES: There are no competing series in this family. A similar soil in another family is the Lazaro soil. Lazaro soils are in the mesic temperature regime and do not have cambic horizons.
GEOGRAPHIC SETTING: Estaban soils are on backslopes of canyons. They formed in colluvium derived from Tertiary age latite and dacite. Slopes are 45 to 90 percent. Elevation ranges from 8,000 to 9,000 feet. The mean annual precipitation is 20 to 26 inches with about 45 percent falling as rain from high-intensity convective thunderstorms between July and September. The mean annual air temperature is 41 to 43 degrees F. The frost-free period is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lucito, Tschicoma, and Urioste soils. Lucito soils are clayey skeletal, have a mollic epipedon, and occur on summits of plateaus. Tschicoma soils are fine-loamy, have an argillic horizon, and occur on toeslopes of valley sides. Urioste soils are very shallow, do not have subsurface diagnostic horizons, and occur on south-facing backslopes of canyons.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; high surface runoff; moderately rapid permeability in the surface and subsoil and very rapid in the substratum.
USE AND VEGETATION: Estaban soils are used for recreation and wildlife habitat. Present vegetation is Douglas fir, white fir, and Rocky Mountain maple.
DISTRIBUTION AND EXTENT: Estaban soils are of small extent on the Jemez Volcanic Field part of the Southern Rocky Mountains province in northcentral New Mexico. The MLRA is 48A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Bandelier National Monument, Los Alamos County, New Mexico; Bandelier National Monument Soil Survey; 2000. Estaban is a place name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon- The zone from 1 to 4 inches. (A horizon)
Cambic horizon- The zone from 4 to 21 inches. (AB and Bw horizons)
Fragmental feature- From 21 to about 84 inches. (C horizon)
Classified according to Soil Taxonomy Second Edition, 1999.