LOCATION ROCKBOUND CAEstablished Series
The Rockbound series consists of shallow and very shallow, excessively drained soils that formed in glacial drift, slope alluvium and colluvium derived predominantly from granodiorite. Due to glaciation some areas have a mix of rock types. The Rockbound soils are on glacial-valley floors and walls in the mountains. Slopes range from 5 to 70 percent. The mean annual precipitation is about 1499 millimeters and the mean annual air temperature is about 6 degrees C.
TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Lithic Xerorthents
TYPICAL PEDON: Rockbound very gravelly loamy sand on an east facing (100 degree), 15 percent slope at an elevation of 2134 meters. When described on 06/18/2002 the soil was dry throughout. Colors are for dry soils unless otherwise noted.
A--0 to 15 cm; brown (10YR 4/3) very gravelly loamy sand, very dark brown (10YR 2/2) rubbed moist; weak fine granular structure; many very fine roots throughout; 35 percent gravel; moderately acid, pH 5.8. (10 to 20 cm thick)
Bw--15 to 20 cm; brown (10YR 5/3) very gravelly loamy sand, dark brown (10YR 3/3) rubbed moist; weak fine granular structure; many very fine roots throughout; 35 percent gravel; moderately acid, pH 5.8. (8 to 30 cm thick)
R--20 cm; Indurated granodiorite bedrock;
TYPE LOCATION: El Dorado County, CA, Between Grass Lake and Angora Peak, 445 meters west and 629 meters south of Section 22, Township 11N, Range 17E, 38 degrees, 52 minutes, 23 seconds North latitude and 120 degrees, 6 minutes, 0 seconds West longitude, NAD83 - U.S.G.S Quad: Echo Lake, California.
RANGE IN CHARACTERISTICS:
Soil moisture: Soil moisture: usually moist but are dry in all parts from mid-July until early October. The soils have a xeric moisture regime.
Depth to lithic contact: 18 to 50 cm
Surface rock fragment content:
20 to 60 percent consisting of: 5 to 25 percent boulders, 5 to 20 percent gravel, 5 to 30 percent cobbles, 5 to 30 percent stones
Reaction: strongly to slightly acid
Control section: the entire soil minus any organic material on the surface.
Rock fragments: 35 to 60 percent, with 35 to 60 percent gravel, 0 to 50 percent cobbles, 0 to 50 percent stones and 0 to 50 percent boulders.
Clay content: averages 3 to 12 percent clay
Mineralogy: mixed
A horizon:
Hue: 10YR
Value: 3 through 5 dry; 2 or 3 moist
Chroma: 2 or 3 dry or moist
Organic matter: 3 to 12 percent
Texture of the fine earth fraction: Loamy sand, loamy coarse sand
Rock fragments: 35 to 60 percent
5 to 60 percent gravel
0 to 40 percent cobbles
0 to 35 percent stones
0 to 40 percent boulders
Bw horizon:
Hue: 10YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 3 or 4 dry; 3 or 4 moist
Organic matter: 2 to 5 percent
Texture of the fine earth fraction: Loamy sand, loamy coarse sand
Rock fragments: 35 to 60 percent
25 to 60 percent gravels
0 to 10 percent cobbles
0 to 10 percent stones
COMPETING SERIES: There are no other series in this family at this time.
GEOGRAPHIC SETTING: The Rockbound soils are on glacial valley floors and walls. Slopes range from 5 to 70 percent. These soils formed in drift and slope alluvium derived predominantly from granodiorite. Elevation is 1910 to 2830 meters. The climate is subhumid with warm dry summers and cold wet winters. The mean annual precipitation is 940 to 1650 millimeters and the mean annual air temperature is 4 to 7 degrees C. The frost free season is 50 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Glenalpine and Dagget soils. The Dagget soils are deep to and have a more closed canopy of trees and the Glenalpine soils are deep predominantly from volcanic materials.
DRAINAGE AND PERMEABILITY: Excessively drained, moderately rapid permeability above the bedrock, very high runoff, no flooding or ponding
USE AND VEGETATION: This soil is used for wildlife and recreation. Vegetation is sparse conifers such as sierra juniper and Jeffrey pine and shrubs huckleberry oak and green leaf manzanita.
DISTRIBUTION AND EXTENT: Rockbound is of moderate extent in California in MLRA 22A -- Sierra Nevada Mountains
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: El Dorado County, (Tahoe Basin Area), California, 2007. Source of name from local valley.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle Size Control Section for this pedon: 0 to 20 cm (the A and Bw horizons)