LOCATION ROCK CREEK WA+ID
Established Series
Rev. JJR/KDPL/KH
09/2019
ROCK CREEK SERIES
Landscape--plateaus, canyonlands
Landform--ridgetops, canyons
Slope--0 to 70 percent
Parent material--residuum derived from basalt mixed with loess
Mean annual precipitation--about 250 to 410 mm
Mean annual air temperature--about 9 degrees C
Depth class--shallow, very shallow
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--mesic
Soil moisture subclass--typic
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Lithic Mollic Haploxeralfs
TYPICAL PEDON: Rock Creek gravelly loam, extremely stony, in an area of grassland
A--0 to 5 cm; gravelly loam, reddish brown (5YR 5/3) dry, dark reddish brown (5YR 3/3) moist; weak medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine vesicular pores; 1 percent surface stones; 5 percent cobbles and 15 percent gravel; neutral (pH 6.6); abrupt smooth boundary
Bt1--5 to 18 cm; cobbly clay loam, reddish brown (5YR 5/4) dry, dark reddish brown (5YR 3/4) moist; weak thick platy structure; hard, firm, moderately sticky and moderately plastic; common fine roots; many fine vesicular pores; 15 percent cobbles and 15 percent gravel; few faint clay films; neutral (pH 6.6); gradual wavy boundary
Bt2--18 to 25 cm; extremely cobbly clay loam, reddish brown (5YR 5/4) dry, dark reddish brown (5YR 3/4) moist; massive; hard, firm, moderately sticky and moderately plastic; few roots forming mats on basalt fragments; 30 percent cobbles, 35 percent gravel, and 5 percent stones; few distinct clay films on basalt fragments and along fracture planes; neutral (pH 6.6); abrupt wavy boundary
Bt3--25 to 36 cm; extremely cobbly clay, brown (7.5YR 4/4) dry, dark brown (7.5YR 3/4) moist; massive; extremely hard, firm, very sticky and moderately plastic; few roots forming mats on basalt fragments; 40 percent cobbles, 40 percent gravel, and 5 percent stones; common distinct clay films on basalt fragments and along fracture planes; neutral (pH 6.6); gradual wavy boundary
R--36 cm; fractured basalt
TYPE LOCATION: Yakima County, Washington, about 1 km east of Fort Simcoe, about 180 m north of State Highway 3B; in the SW1/4SE1/4 of section 16, T. 10 N., R. 16 E., Willamette Meridian; latitude 46.34707332, longitude -120.8253860, datum WGS 84 (coordinates estimated from section, township, and range)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature at lithic contact--8 to 11 degrees C
Depth to lithic contact--20 to 50 cm
Particle-size control section--35 to 45 percent clay; 35 to 90 percent rock fragments
Percentage of surface covered with rock fragments--0 to 3 percent
Reaction--6.1 to 7.3
A horizon
Hue--5YR, 7.5YR, 10YR
Value--4 or 5 dry, 2 to 4 moist
Chroma--2 or 3 dry or moist
Texture of fine-earth fraction--loam, clay loam, silt loam
Gravel content--0 to 60 percent
Cobble content--0 to 60 percent
Stone content--0 to 15 percent
Thickness--3 to 8 cm
Bt horizon
Hue--5YR, 7.5YR
Value--4 or 5 dry, 3 or 4 moist
Chroma--2 to 4 dry, 2 or 3 moist
Texture of fine-earth fraction--silty clay loam, clay loam, silty clay, clay
Gravel content--15 to 60 percent
Cobble content--15 to 60 percent
Stone content--0 to 15 percent
Clay films--on faces of peds and rock fragments
Combined thickness--10 to 46 cm
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--370 to 1275 m
Climate--warm, dry summers; cool, moist winters
Mean annual precipitation--250 to 410 m
Mean annual air temperature--8 to 10 degrees C
Frost-free season--120 to 170 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Clint--mollic epipedon; no argillic horizon; on side slopes
Harwood--mollic epipedon; 50 to 100 cm (moderately deep) to a duripan; on uplands and dissected terraces
McDaniel--mollic epipedon; no lithic contact within a depth of more than 150 cm; on canyon side slopes and hillslopes
Simcoe--mollic epipedon; 50 to 100 cm (moderately deep) to a lithic contact (basalt); on hillslopes
Taneum--mollic epipedon; no lithic contact within a depth of 100 cm or more; less than 15 percent coarse fragments; on mountain slopes and hillslopes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturated hydraulic conductivity (Ksat)--moderately high
USE AND VEGETATION:
Use--livestock grazing, wildlife habitat
Native vegetation--bluegrass, bluebunch wheatgrass, bighead clover, hooker balsamroot, biscuitroot, stiff (scab) sagebrush, eriogonum, phlox, wild onion, violet, windflower
DISTRIBUTION AND EXTENT: Southern and eastern Washington; MLRA 8; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yakima County, Washington; 1970
REMARKS:
Diagnostic horizons and other features recognized in this pedon
*Ochric epipedon
*Argillic horizon--zone from 5 to 36 cm
*Depth to lithic contact--36 cm
*Particle-size control section--zone from 5 to 36 cm
*Mollic feature--value of 3 moist to a depth of 38 cm; 0.7 percent organic carbon or more in upper 10 cm
National Cooperative Soil Survey
U.S.A.