LOCATION COOKCREEK ORTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Vitrandic Haploxerolls
TYPICAL PEDON: Cookcreek very gravelly ashy silt loam shrub steppe, on a 90 percent planar northeast-facing slope at an elevation of 2,170 feet. (Colors are for moist soil unless otherwise noted.)
A--0 to 13 inches; black (10YR 2/1) very gravelly ashy silt loam, dark grayish brown (10YR 4/2) dry; weak medium and fine granular structure; soft, friable, slightly sticky and slightly plastic; many fine roots; few medium and common fine irregular pores; neutral (pH 7.0); 30 percent gravel and 5 percent cobbles and 2 percent stones; gradual smooth boundary. (4 to 13 inches thick)
AB--13 to 24 inches; dark brown (10YR 3/3) very gravelly loam, yellowish brown (10YR 5/4) dry; weak fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common fine roots; few fine tubular and common fine irregular pores; 35 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.0); gradual smooth boundary. (8 to 11 inches thick)
BC--24 to 35 inches; brown (10YR 4/3) very gravelly loam, yellowish brown (10YR 5/4) dry; massive; soft, very friable, slightly sticky and slightly plastic; few fine tubular pores; 45 percent gravel and 5 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary.
R--35 inches; fractured, indurated metavolcanic rock.
TYPE LOCATION: Wallowa County, Oregon
Section 24 (SE 1/4, NE 1/4, NE 1/4), T. 05 N., R. 47 E.
Latitude 45 degrees, 54 minutes, 8.3 seconds N
Longitude 116 degrees, 52 minutes, 29.1 seconds W
UTM coordinates: zone 11, north 5082982.8 meters, east 509715.7 meters; NAD27
USGS Quadrangle: Wapshilla Creek
RANGE IN CHARACTERISTICS:
Soil Temperature: mesic regime
Mean Annual Soil Temperature: 48 to 51 degrees F
Mean Summer Soil Temperature: 60 to 64 degrees F
Mean Winter Soil Temperature: 31 to 34 degrees F
Soil Moisture: xeric regime; dry 60 to 90 consecutive days in summer
Particle-size Control Section: from 10 inches below mineral soil surface to bedrock
clay content, average : 12 to 18 percent
rock fragment content, average: 40 to 70 percent
Diagnostic Horizons and Features:
vitrandic subgroup properties: from the mineral soil surface 7 to 13 inches thick
Al+1/2Fe (ammonium oxalate): 0.3 to 0.9 percent
glass content in the 0.02-2.0 mm fraction: 5 to 15 percent
mollic epipedon: 20 to 25 inches thick
lithic contact, depth below mineral soil surface: 20 to 40 inches
A horizon:
color, moist: 10YR 2/1, 3/1, 3/2; 2.5Y 3/2
color, dry: 10YR 3/2, 4/2, 4/3, 5/3; 2.5Y 5/2
texture: GRV-ASHY-SIL, GRV-ASHY-L, CBV-ASHY-SIL
clay content: 10 to 14 percent
rock fragment content: 35 to 45 percent total
gravel: 15 to 35 percent
cobbles: 5 to 15 percent
stones: 0 to 5 percent
reaction: neutral; pH: 6.6 to 7.3
AB horizon; Bw in some pedons:
color, moist: 10YR 3/2, 3/3; 2.5Y 3/2
color, dry: 10YR 4/4, 5/2, 5/4; 2.5Y 5/2
texture: GRV-L, CBV-L
clay content: 12 to 17 percent
rock fragment content: 40 to 55 percent total
gravel: 15 to 40 percent
cobbles: 5 to 25 percent
stones: 0 to 5 percent
reaction: neutral to moderately alkaline; pH: 6.6 to 8.4
BC horizon; includes C horizon in some pedons:
color, moist: 10YR 4/3, 5/3; 2.5Y 4/2
color, dry: 10YR 5/4, 6/4; 2.5Y 6/2
texture: GRV-L, CBV-L, GRX-L, CVX-SL
clay content: 10 to 19 percent
rock fragment content: 50 to 85 percent total
gravel: 20 to 65 percent
cobbles: 5 to 55 percent
stones: 0 to 5 percent
non-effervescent to strongly effervescent
reaction: neutral to moderately alkaline; pH: 6.6 to 8.4
COMPETING SERIES:
Brickmill soils - very deep (lacks a lithic contact within 60 inches); formed in relict alluvium; mollic epipedon 10 to 20 inches thick; redox features at 30 to 40 inches (oxyaquic)
Eaglespring soils - deep (40 to 60 inches) to a lithic contact (sedimentary lithology)
Foggydew soils deep (40 to 60 inches) to a lithic contact (andesite); dry 90 to 105 consecutive days in summer
Garrison soils - very deep (lacks a lithic contact within 60 inches); formed in glacial outwash; mollic epipedon 12 to 20 inches thick; secondary carbonates at 44 inches or more
Metmill soils very deep (lacks a lithic contact within 60 inches) formed in alluvium; mollic epipedon 30 to 60 inches thick; redox features at 20 to 30 inches (oxyaquic); dry 60 to 75 consecutive days in summer
Neviot soils - very deep (lacks a lithic contact within 60 inches); formed in colluvium from basalt; secondary carbonates at 44 inches or more; dry 100 to 120 consecutive days in summer
Northstar soils - moderately deep (20 to 40 inches) to a lithic contact (rhyodacite); O horizons, 2 inches thick; mollic epipedon 8 to 15 inches thick; base saturation (sum of cations) less than 75 percent in one or more horizons between 10 and 30 inches (ultic); dry 75 to 90 consecutive days in summer
Opportunity soils - very deep (lacks a lithic contact within 60 inches); formed in glacial outwash; mollic epipedon 10 to 20 inches thick; secondary carbonates at 44 inches or more; sandy-skeletal material at 36 to 60 inches
Peka soils deep (40 to 60 inches) to densic contact (dense till from granite); O horizon 1 inch thick; mollic epipedon 10 to 18 inches thick; dry 75 to 90 consecutive days in summer
Thuso soils very deep (greater than 60 inches deep) formed in colluvium; mollic epipedon 10 to 25 inches thick; dry 90 to 105 consecutive days in summer
Wagberg soils - greater than 40 inches deep (till); mollic epipedon 10 to 18 inches thick; dry 90 to 105 consecutive days in summer
GEOGRAPHIC SETTING:
Landform: backslopes of canyons and plateaus
Slope gradient: 40 to 90 percent
Parent material: Mazama volcanic ash mixed with loess and colluvium
Lithology: metavolcanic rock or argillite
Elevation: 2,000 to 2,800 feet
Climate: cool, moist winters and hot, dry summers
Mean annual precipitation: 10 to 15 inches
Mean annual air temperature: 47 to 49 degrees F
Frostfree period: 95 to 200 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Cabincreek: on concave slopes and lower backslopes; deep to a lithic contact (metavolcanic); mixed ash and loess mantle, and mollic epipedon 20 to 40 inches thick; under common snowberry, rose, ninebark, silky lupine, mouse-ear, Idaho fescue and bluebunch wheatgrass
DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderate
USE AND VEGETATION:
Use: recreation, wildlife habitat, livestock grazing and watershed
Potential natural vegetation: Idaho fescue, bluebunch wheatgrass, silky lupine, arrowleaf balsamroot, yarrow and deerhorn.
Plant association: FEID-AGSP (Idaho fescue-bluebunch wheatgrass); may include FEID-AGSP/LUSE(Idaho fescue-bluebunch wheatgrass/ silky lupine) or FEID-AGSP/BASA(Idaho fescue-bluebunch wheatgrass/ arrowleaf balsamroot)
DISTRIBUTION AND EXTENT:
Distribution: MLRA: B9; Northeast Oregon, Blue Mountain foothills
Extent: small
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Wallowa-Whitman National Forest, Oregon 2008. Name is from Cook Creek.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon: 0 to 24 inches; A, AB horizons
vitrandic subgroup properties (ash influenced layer): 0 to 13 inches; A horizon
particle-size control section: 10 to 35 inches; A, AB, BC horizons