LOCATION DUNDERBERG CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Vitrandic Haplocryolls
TYPICAL PEDON: Dunderberg very gravelly ashy sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 55 percent gravel, 2 percent stones, and 2 percent boulders.
A1--0 to 5 inches; dark grayish brown (10YR 4/2) very gravelly ashy sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; common very fine interstitial pores; 55 percent gravel; slightly acid; clear smooth boundary. (3 to 6 inches thick)
A2--5 to 9 inches; dark grayish brown (10YR 4/2) extremely gravelly ashy sandy loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and many fine roots; common very fine tubular and common very fine and fine interstitial pores; 55 percent gravel and 15 percent cobbles; slightly acid; clear wavy boundary. (4 to 7 inches thick)
A3--9 to 19 inches; dark grayish brown (10YR 4/2) extremely cobbly ashy sandy loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many very fine and many fine roots; common very fine tubular and common very fine and fine interstitial pores; 40 percent gravel and 45 percent cobbles; slightly acid; clear wavy boundary. (0 to 11 inches thick)
Bw1--19 to 28 inches; brown (10YR 5/3) extremely cobbly ashy sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and common fine roots; common very fine tubular and common very fine and fine interstitial pores; 50 percent gravel and 35 percent cobbles; slightly acid; clear wavy boundary. (8 to 12 inches thick)
Bw2--28 to 39 inches; brown (7.5YR 5/4) extremely gravelly ashy sandy loam, dark brown (7.5YR 3/4) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and few fine roots; common very fine tubular and common very fine and fine interstitial pores; few faint clay bridges between sand grains; 65 percent gravel and 20 percent cobbles; slightly acid; clear wavy boundary. (8 to 14 inches thick)
Bw3--39 to 60 inches; yellowish brown (10YR 5/4) extremely gravelly sandy loam, dark yellowish brown (10YR 3/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine, few fine, and few medium roots; common very fine interstitial pores; 65 percent gravel and 20 percent cobbles; slightly acid.
TYPE LOCATION: Mono County, California; on the Toiyabe National Forest about 2.8 miles southwest of Conway Summit; approximately 1,450 feet north and 150 feet east of the southwest corner of section 33, T. 3 N., R. 25 E.; USGS Lundy 7.5 minute topographic quadrangle; 38 degrees 04 minutes 25.0 seconds north latitude and 119 degrees 13 minutes 49.2 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during late fall, winter, and spring; dry from July through early October; Xeric moisture regime.
Mean annual soil temperature - 44 to 47 degrees F.
Mean summer soil temperature - 53 to 59 degrees F.
Mollic epipedon thickness - 16 to 30 inches; includes the Bw1 horizon.
Particle-size control section - Clay content: Averages 8 to 18 percent; Rock fragments: Averages 60 to 85 percent, mainly gravel and cobbles. Lithology of fragments are mixed igneous and metamorphic rocks such as granodiorite, andesite, schist, and gneiss.
A1 and A2 horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 3 to 5 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 15 to 45 percent in coarse silt through fine sand fractions.
A3 and Bw1 horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 15 to 30 percent in coarse silt through fine sand fractions.
Bw2 horizon - Hue: 7.5YR through 2.5Y.
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Extremely cobbly ashy sandy loam or extremely gravelly ashy sandy loam.
Clay content: 8 to 18 percent.
Rock fragments: 60 to 85 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 15 to 30 percent in coarse silt through fine sand fractions.
Bw3 horizon - Hue: 7.5YR through 2.5Y.
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Extremely cobbly sandy loam or extremely gravelly sandy loam.
Clay content: 8 to 18 percent.
Rock fragments: 60 to 85 percent.
Reaction: Slightly acid or neutral.
COMPETING SERIES: These are the Lagall and Lowland series.
Lagall soils have mean summer soil temperature of 43 to 46 degrees F., have mollic epipedons 10 to 15 inches thick, and have a udic moisture regime. Lowland soils have mean annual soil temperature of 38 to 42 degrees F., have mollic epipedons 8 to 16 inches thick, and have an ustic moisture regime.
GEOGRAPHIC SETTING: Dunderberg soils are on moraines. They typically occur on shoulder positions. They formed in till derived from igneous and metamorphic rocks such as granodiorite, andesite, schist, and gneiss with surficial additions of eolian volcanic ash. The probable sources of the volcanic ash are the Mono Craters and Long Valley Caldera in eastern California. Slopes are 8 to 30 percent. Elevations range from 8,000 to 9,500 feet. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 30 to 45 inches, mean annual temperature is 36 to 40 degrees F., and the frost-free period is 40 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aspetill and Conwayridge soils. Aspetill soils have an argillic horizon. Conwayridge soils have a frigid soil temperature regime and have mollic epipedons less than 16 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; low surface runoff; moderately rapid permeability (high saturated hydraulic conductivity).
USE AND VEGETATION: Dunderberg soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly low-stature mountain big sagebrush, snowberry, western needlegrass, bluegrass, and sedge.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 5,000 acres of the series mapped to date. MLRA 22A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mono County (Toiyabe National Forest Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 28 inches (A1, A2, A3, and Bw1 horizons).
Cambic horizon - The zone from 28 to 60 inches (Bw2 and Bw3 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 30 inches (A1, A2, A3, and Bw1 horizons and part of the Bw2 horizon).
Particle-size control section - The zone from 10 to 40 inches (Bw1 and Bw2 horizons and parts of the A3 and Bw3 horizons).
ADDITIONAL DATA: Volcanic glass content determined locally by optical grain counts using a polarizing petrographic microscope.