LOCATION IDRIAPEAK CA
Established Series
Rev. KDA-BRY-KP
12/2022
IDRIAPEAK SERIES
The Idriapeak series consists of moderately deep, well drained soils on mountain slopes. These soils formed in colluvium over residuum weathered from serpentinite. Slope is 20 to 50 percent. The mean annual precipitation is about 21 inches (53 centimeters) and the mean annual temperature is about 14 degrees C (57.2 degrees F).
TAXONOMIC CLASS: Loamy-skeletal, magnesic, thermic Mollic Haploxeralfs
TYPICAL PEDON: Idriapeak gravelly sandy loam-on a south aspect slope of 32 percent under chamise, bigberry manzanita, buckbrush and Coulter pine. The elevation is about 1,143 meters (3,750 feet). (Color is for dry soil unless otherwise stated. When described on April 6, 2009 the soil was slightly moist throughout.) The surface is covered by 50 percent 2 to 75 millimeter serpentine pebbles and 10 percent 75 to 250 millimeter serpentine cobbles.
A--0 to 5 centimeters (0 to 2 inches); reddish brown (5YR 4/4) gravelly sandy loam, dark reddish brown (5YR 3/3) moist; weak thin platy parting to weak medium subangular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular pores; 23 percent, 2 to 75 millimeter pebbles; neutral (pH 6.7); abrupt smooth boundary
Bt1--5 to 15 centimeters (2 to 6 inches); reddish brown (5YR 4/4) gravelly loam, dark reddish brown (5YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine, fine, medium, and coarse roots; common very fine tubular pores; common discontinuous distinct clay films on faces of peds and along surfaces of pores; 22 percent, 2 to 75 millimeter pebbles; neutral (pH 7.2); clear wavy boundary.
Bt2--15 to 25 centimeters (6 to 10 inches); reddish brown (5YR 4/4) gravelly loam, dark reddish brown (5YR 3/4) moist; moderate medium subangular blocky structure; moderately hard, firm, very sticky and moderately plastic; common very fine, fine, medium, coarse, and very coarse roots; common very fine and fine tubular pores; few discontinuous distinct clay films on faces of peds and along surfaces of pores; 30 percent, 2 to 75 millimeter pebbles; neutral (pH 7.3); abrupt wavy boundary.
Bt3--25 to 44 centimeters (10 to 17 inches); brown (7.5YR 4/4) very gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; moderately hard, firm, very sticky and moderately plastic; common very fine, fine, medium, coarse, and very coarse roots; common very fine tubular pores; few discontinuous distinct clay films on faces of peds and along surfaces of pores; 46 percent, 2 to 75 millimeter pebbles; slightly alkaline (pH 7.4); abrupt wavy boundary.
Bt4--44 to 61 centimeters (17 to 24 inches); brown (7.5YR 4/4) very gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; moderately hard, firm, very sticky and moderately plastic; common fine roots; common very fine tubular pores; few discontinuous distinct clay films on faces of peds and along surfaces of pores; 50 percent, 2 to 75 millimeter pebbles; slightly alkaline (pH 7.5); gradual wavy boundary.
Bt5--61 to 92 centimeters (24 to 36 inches); dark yellowish brown (10YR 3/4) very gravelly sandy clay loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common very fine and fine tubular pores; few discontinuous distinct clay films on faces of peds and along surfaces of pores; 46 percent, 2 to 75 millimeter pebbles and 5 percent 75 to 250 millimeter cobbles; slightly alkaline (pH 7.5); abrupt wavy boundary.
R--92 to 127 centimeters (36 to 50 inches); lithic contact; strongly cemented serpentinite with cracks greater than 10 centimeters (4 inches) apart.
TYPE LOCATION: San Benito County, California, in Clear Creek Management Area; about 1.9 kilometers (1.2 miles) south-southwest of Idria Peak; 287 meters (942 feet) south and 256 meters (840 feet) west of the northeast corner of section 15, T. 18 S., R. 11 E., Mount Diablo Base and Meridian; latitude 36 degrees, 22 minutes, 52.8 seconds north and longitude 120 degrees, 41 minutes, 36.3 seconds west; USGS Idria, California Quadrangle, NAD83.
RANGE IN CHARACTERISTICS: Depth to lithic contact is 51 to 102 centimeters (20 t0 40 inches). Surface fragments are composed of serpentinite; 20 to 50 percent, 2 to 75 millimeter pebbles and 0 to 20 percent, 75 to 250 millimeter cobbles.
A horizon:
Hue: 5YR or 10YR dry and moist
Value: 3 to 5 dry and 3 or 4 moist
Chroma: 2 to 5 dry and 2 to 4 moist
Texture of the fine earth fraction: sandy loam, loam, and sandy clay loam
Content of clay: 10 to 27 percent
Content of organic matter: 4.0 to 7.0
Reaction: Neutral
Content of rock fragments: 10 to 40 percent, 2 to 75 millimeter gravel and 0 to 15 percent, 75 to 250 millimeter cobbles.
Bt horizon:
Hue: 5YR, 7.5YR, or 10YR dry and moist
Value: 3 to 6 dry and 3 or 4 moist
Chroma: 4 or 5 dry and 2 to 4 moist
Texture of the fine earth fraction: loam, clay loam, and sandy clay loam
Content of clay: 15 to 34 percent
Content of organic matter: 0.2 to 3.5 percent
Reaction: neutral or slightly alkaline
Content of rock fragments: 15 to 60 percent, 2 to 75 millimeter gravel and 0 to 15 percent, 75 to 250 millimeter cobbles.
COMPETING SERIES: There are no competing series at this time.
GEOGRAPHIC SETTING: Idriapeak soils are on mountain slopes at elevations of 794 to 1,598 meters (2,605 to 5,243 feet). Slope is 20 to 50 percent. Idriapeak soils formed in colluvium over residuum derived from serpentinite. The climate consists of hot dry summers and cool moist winters. Mean annual precipitation is 483 to 610 millimeters (19 to 24 inches). Mean annual temperature is 9 to 17 degrees C (48.2 to 62.6 degrees F). Frost-free period is 150 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Atravesada,
Duckworth, and
Delmexico soils. Atravesada soils are shallow with a loamy particle size class. Duckworth and Delmexico soils have a fine-loamy particle size class.
DRAINAGE AND PERMEABILITY: Well drained; medium or high runoff; moderately high saturated hydraulic conductivity.
USE AND VEGETATION: These soils are used for recreation and wildlife. Many areas have abandoned asbestos mines. The vegetation is chamise, manzanita, buckbrush,and Coulter pine.
DISTRIBUTION AND EXTENT: These soils are in Clear Creek Management Area, San Benito County, CA, in the California Coast Ranges. They are not extensive. MLRA 15.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Benito County, California, 2011. Named after Idriapeak Mine.
REMARKS: These were formerly mapped as Henneke soils in San Benito County, 1969. They are being differentiated by having a loamy-skeletal particle size control section.
ADDITIONAL DATA: The modal pedon ID for the Idriapeak Series is S09CA069003 (Pedon Number 09N0922). Additional supporting pedons are 90CA069065, 90CA069015, 90CA069088, and 90CA069003. Mean annual soil temperature at a depth of 50 cm (20 inches) is 16.7 degrees C (62 degrees F) at the typical profile site, based on 1 year's data (8/1/2009-8/1/2010) measured with a Onset Soil Temperature Recorder.
National Cooperative Soil Survey
U.S.A.