LOCATION LAVASPRING CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Aquandic Cryaquolls
TYPICAL PEDON: Lavaspring mucky ashy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 5 percent gravel.
A1--0 to 3 inches; dark grayish brown (10YR 4/2) mucky ashy loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, many fine, and many medium roots; many very fine interstitial pores; 5 percent gravel; slightly acid; clear wavy boundary. (1 to 5 inches thick)
A2--3 to 7 inches; dark grayish brown (10YR 4/2) ashy loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, many, fine, and many medium roots; many very fine interstitial and common very fine tubular pores; common fine distinct dark yellowish brown (10YR 4/4) moist irregular masses of iron accumulation in the matrix; 10 percent gravel; slightly acid; abrupt smooth boundary. (3 to 6 inches thick)
A3--7 to 11 inches; dark grayish brown (10YR 4/2) extremely gravelly loamy coarse sand, very dark brown (10YR 2/2) moist; single grain; loose, nonsticky and nonplastic; many very fine, many fine, and many medium roots; many very fine and fine interstitial pores; common fine distinct brown (7.5YR 4/4) moist irregular masses of iron accumulation in the matrix; 65 percent gravel; neutral; abrupt smooth boundary. (0 to 6 inches thick)
A4--11 to 20 inches; very dark gray (10YR 3/1) clay loam, black (N 2.5/0) moist; strong fine and medium subangular blocky structure; slightly hard, very friable, very sticky and moderately plastic; common very fine, many fine, and many medium roots; common very fine tubular and interstitial pores; common fine prominent brown (7.5YR 4/4) moist irregular masses of iron accumulation in the matrix; 5 percent gravel; neutral; clear wavy boundary. (7 to 16 inches thick)
A5--20 to 31 inches; gray (10YR 5/1) loam, black (10YR 2/1) moist; weak coarse prismatic structure; very hard, firm, moderately sticky and moderately plastic; common very fine, common fine, and common medium roots; common very fine tubular and few very fine interstitial pores; common fine distinct dark yellowish brown (10YR 3/4) moist irregular masses of iron accumulation in the matrix; 10 percent gravel; neutral; clear wavy boundary. (8 to 16 inches thick)
A6--31 to 37 inches; grayish brown (10YR 5/2) gravelly coarse sandy loam, very dark grayish brown (10YR 3/2) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine, few fine, and few medium roots; common very fine tubular and interstitial pores; common distinct dark yellowish brown (10YR 4/4) moist irregular masses of iron accumulation in the matrix; 30 percent gravel; neutral; clear wavy boundary. (3 to 15 inches thick)
A7--37 to 60 inches; grayish brown (10YR 5/2) extremely gravelly coarse sandy loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; few very fine and few fine roots; common very fine tubular and interstitial pores; common fine and medium distinct dark yellowish brown (10YR 3/4) moist irregular masses of iron accumulation in the matrix; 70 percent gravel; neutral.
TYPE LOCATION: Mono County, California; on the Toiyabe National Forest along Burcham Creek; approximately 1,520 feet south and 1,080 feet west of the northeast corner of section 10, T. 6 N., R. 23 E.; USGS Chris Flat 7.5 minute topographic quadrangle; 38 degrees 23 minutes 01.5 seconds north latitude and 119 degrees 25 minutes 56.5 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually saturated in some part of the moisture control section during winter, spring, and early summer, usually dry in all parts during summer and fall; Xeric moisture regime with seasonal periods of aquic moisture regime from November through June during saturation with ground water and anaerobic conditions.
Mean annual soil temperature - 42 to 47 degrees F.
Mean summer soil temperature - 52 to 59 degrees F.
Mollic epipedon thickness - 30 to 60 inches.
Thickness of ashy subhorizons - 7 to 11 inches, occurring immediately below the soil surface.
Particle-size control section - Clay content: Averages 18 to 25 percent; strata in the upper part average 18 to 28 percent and strata in the lower part average 8 to 18 percent.
Rock fragments: Averages 15 to 35 percent, mainly gravel. Lithology of fragments is granitic rocks such as granodiorite, volcanic rocks such as tuff or andesite, and minor metamorphic rocks such as quartzite.
A1 and A2 horizons - Hue: 10YR or neutral (N).
Value: 3 or 4 dry.
Chroma: 1 or 2 dry, 0 (when hue is N), 1, or 2 moist.
Organic matter content: 6 to 10 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 5 to 25 percent in the coarse silt through fine sand fractions.
Oxalate extractable aluminum plus one-half oxalate iron: 0.2 to 0.4 percent.
A3, A4, and A5 horizons (stratified subhorizons in the upper part of the particle-size control section - Hue: 10YR or neutral (N).
Value: 3 through 5 dry.
Chroma: 1 or 2 dry, 0 (when hue is N) 1, or 2 moist.
Texture: Stratified extremely gravelly loamy coarse sand to clay loam; loam or clay loam textures predominate.
Clay content: Averages 18 to 28 percent.
Rock fragments: Averages 15 to 35 percent.
Organic matter content: 3 to 5 percent.
Reaction: Slightly acid or neutral.
A6 and A7 horizon (stratified subhorizons in the lower part of the particle-size control section and below - Hue: 10YR or 2.5Y.
Value: 4 or 5 dry, 2 or 3 moist.
Texture: Stratified extremely gravelly coarse sandy loam to gravelly sandy loam.
Clay content: 8 to 18 percent.
Rock fragments: Averages 50 to 80 percent.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.
COMPETING SERIES: This is the
Gerow (T) series.
Gerow soils have 27 to 35 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Lavaspring soils are on stream terraces and flood plains. They formed in alluvium derived mainly from mixed igneous rocks such as granodiorite, tuff, and andesite, minor amounts of metamorphic rock such as quartzite, and 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 0 to 4 percent. Elevations range from 7,000 to 9,000 feet. The climate is continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 16 to 25 inches, the mean annual temperature is 40 to 44 degrees F., and the frost-free period is 40 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Trespass soil. Trespass soils are loamy-skeletal and have argillic horizons.
DRAINAGE AND PERMEABILITY: Poorly drained; very high surface runoff; moderately slow permeability (moderately high saturated hydraulic conductivity). Endosaturation is present with an apparent seasonal high water table between the soil surface and 20 inches (very shallow or shallow free water occurrence classes) from November through June. Cumulative annual duration classes are Common or Persistent. Some areas of these soils are susceptible to occasional flooding for brief periods between December and June.
USE AND VEGETATION: Lavaspring soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly sedges and rushes.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 1,300 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 60 inches (A1, A2, A3, A4, A5, A6, and A7 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 7 inches (A1 and A2 horizons).
Aquic conditions - The conditions of endosaturation and reduction in horizons between the soil surface and 60 inches at certain times in normal years (A1, A2, A3, A4, A5, A6, and A7 horizons).
Particle-size control section - The zone from 10 to 40 inches (A4, A5, and A6 horizons and parts of the 2A3 and 4A7 horizons).