LOCATION CLARKSCREEK             OR

Established Series
Rev. RJO/JLW/DAL
10/2012

CLARKSCREEK SERIES

The Clarkscreek series consists of moderately deep, well drained soils on glaciated mountain slopes. Clarkscreek soils formed in till from mixed rocks, mixed with volcanic ash and loess in surface horizons. Slopes are 0 to 90 percent. Mean annual precipitation is about 53 inches and mean annual temperature about 36 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, isotic Haploxerandic Humicryepts

TYPICAL PEDON: Clarkscreek gravelly ashy loam - rangeland with scattered trees, on a 22 percent southeastfacing slope at an elevation of 7,100 feet. (Colors are for moist soil unless otherwise noted.)

A1--0 to 9 inches; dark brown (10YR 3/3) gravelly ashy loam, brown (10YR 5/3) dry; weak medium to fine subangular blocky structure parting to medium granular; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots throughout; common very fine irregular pores; 15 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (7 to 14 inches thick)

A2--9 to 19 inches; dark brown (10YR 3/3) very gravelly ashy loam, yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots throughout; few very fine irregular and few fine tubular pores; 30 percent gravel and 5 percent cobbles; moderately acid (pH 6.0); abrupt smooth boundary. (3 to 11 inches thick)

Bw--19 to 30 inches; dark yellowish brown (10YR 3/4) very gravelly loam, yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure; soft, friable, nonsticky and nonplastic; few very fine roots throughout; few very fine tubular pores; 30 percent gravel and 10 percent cobbles; moderately acid (pH 6.0); abrupt boundary. (6 to 16 inches thick)

R--30 inches; basalt

TYPE LOCATION: Baker County, Oregon
Section 9 (NE 1/4, SE 1/4, NW 1/4), T. 6 S., R. 46 E.
Latitude: 45 degrees, 3 minutes, 44 seconds north
Longitude: 117 degrees, 5 minutes, 17 seconds west
UTM Coordinates: zone 11; 4989649.1 northing, 493067.2 easting; NAD27
USGS Quadrangle: Deadman Point

RANGE IN CHARACTERISTICS:
Soil Temperature: cryic regime
Mean Annual Soil Temperature: 35 to 40 degrees F
Mean Summer Soil Temperature: 41 to 47 degrees F
Mean Winter Soil Temperature: 28 to 36 degrees F
Soil Moisture: xeric regime; dry 45 to 60 consecutive days in summer

particle-size control section: from 10 inches below the mineral surface to a lithic contact
clay content, average: 7 to 15 percent
rock fragment content, average: 35 to 65 percent
rock fragment shape: rounded or subrounded

andic subgroup properties: upper boundary at the mineral soil surface; 7 to 14 inch thick ash mantle
Al+1/2Fe(aox): 1.0 to 2.0 percent
bulk density: 0.65 to 0.85 g/cc
P retention: 55 to 75 percent
0.02-2.0 mm fraction: 60 to 70 percent of fine earth
glass content in the 0.02-2.0 mm fraction: 25 to 55 percent
water content 1500 kPa water (air dried): 10 to 12 percent
8Si + 2Fe (aox): 3 to 5 percent
umbric epidedon: 10 to 24 inches thick
cambic horizon: 6 to 16 inches thick
lithic contact, depth: 20 to 40 inches

A1 horizon:
color, moist: 2.5Y 3/2; 10YR 3/2, 3/3
color, dry: 2.5Y 5/2; 10YR 5/3, 5/4
texture: GR-ASHY-L, GR-ASHY-SL
clay content: 7 to 15 percent
rock fragment content: 15 to 35 percent
gravel: 15 to 25 percent
cobbles: 0 to 5 percent
stones: 0 to 5 percent
reaction: strongly acid; pH: 5.1 to 6.0
base saturation (NH4OAc): 35 to 50 percent

A2 horizon; (AB horizon in some pedons):
color, moist: 2.5Y 3/2; 10YR 3/3
color, dry: 2.5Y 5/4; 10YR 5/3, 5/4
texture: GRV-ASHY-SL, STV-ASHY-L, GRV-ASHY-SIL, CBV-ASHY-L, GRV-ASHY-L
clay content: 7 to 15 percent
rock fragment content: 35 to 55 percent
gravel: 20 to 40 percent
cobbles: 5 to 15 percent
stones: 0 to 20 percent
reaction: strongly acid; pH: 5.1 to 6.0
base saturation: 40 to 60 percent

Bw horizon; (also BC or 2C horizons in some pedons):
color, moist: 2.5Y 4/4, 5/4; 10YR 3/4, 4/3, 5/4
color, dry: 2.5Y 5/4, 6/4; 10YR 5/3, 5/4, 7/4
texture: STX-L, CBX-SL, STX-SIL, CBX-L, CBV-SL, GRV-L
clay content: 7 to 15 percent
rock fragment content: 40 to 90 percent
gravel: 15 to 45 percent
cobbles: 10 to 70 percent
stones: 0 to 45 percent
reaction: strongly acid to moderately acid; pH: 5.1 to 6.0
base saturation: 50 to 75 percent

COMPETING SERIES:
Growden: very deep, formed in colluvium from siliceous rocks with a mantle of volcanic ash; no cambic horizon; base saturation (NH4OAc) less than 50 percent in one-half or more of the thickness between 10 and 30 inches
Puzzlecreek: formed in colluvium from basalt mixed with volcanic ash and loess in surface horizons; rock fragments are angular to subangular in shape
Rockcreekbutte (T): formed in colluvium from granite mixed with volcanic ash in surface horizons; rock fragments are subangular to subrounded in shape; base saturation (NH4OAc) 20 to 40 percent between 10 and 30 inches;
Rustlerpeak: moderately deep (20 to 40 inches) to a paralithic contact; 20 to 35 percent clay in the particle-size control section

GEOGRAPHIC SETTING:
Landform: glaciated mountain slopes
Slope gradient: 0 to 90 percent
Parent material: volcanic ash and loess mixed with till
Lithology: mixed, dominantly basalt, andesite, or andesitic basalt
Elevation: 5,800 to 7,200 feet
Climate: cold, wet winters and cool, dry summers
Mean annual precipitation: 40 to 55 inches
Mean annual temperature: 33 to 38 degrees F
Frost-free period: 15 to 60 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Angelbasin: on backslopes of glacially scoured mountains; thin volcanic ash mantle
Bearpawmeadow: on glacially scoured convex backslopes; moderately deep; under closed forest canopy
Burgerbutte: on shoulders and backslopes; shallow to bedrock; under grassland or mountain shrub
Dollarlake: on planar or concave glaciated footslopes; very deep; under alpine meadow
Ducklake: on glacial moraines; 40 to 60 inches to densic contact; ash mantle more than 14 inches thick
Crawfish: on ridgetops, side slopes and shoulders; very shallow; grasslands, has volcanic ash influence
Eastlakesbasin: on convex backslopes and shoulders; shallow to bedrock; under grassland
Haashollow: on concave glaciated backslopes and footslopes; very deep; under closed forest canopy; thick volcanic ash mantle
Marblepoint: on glaciated footslopes; very deep; under a closed forest canopy
Moodybasin: on moraines in glaciated valleys; moderately deep to a densic contact; under a fescue, lupine and scattered subalpine fir
Mudlakebasin: on gently sloping glaciated basins; ash mantle more than 14 inches thick

DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderately rapid

USE AND VEGETATION:
Use: watershed, wildlife habitat and recreation.
Native vegetation: subalpine fir, lodgepole pine, whitebark pine, grouse huckleberry, false hellebore, spurred lupine, western hawkweed, common yarrow, penstemons, larkspur, elk sedge and green fescue
Plant Association: FEVI/LULA3 (green fescue/spurred lupine); may include ABLA/CAGE (subalpine fir/elk sedge)

DISTRIBUTION AND EXTENT:
Distribution: Central Rocky and Blue Mountain Foothills; MLRA 10
Extent: small

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Wallowa-Whitman National Forest, Oregon 2012.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
umbric epipedon: 0 to 19 inches; A1, A2 horizons
cambic horizon: 19 to 30 inches; Bw horizon
andic subgroup properties: 0 to 9 inches; A1 horizon
particle-size control section: 10 to 30 inches; A2, Bw horizons
eutric subgroup properties: more than one-half the thickness between 10 and 30 inches has a base saturation of more than 50 percent

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National Cooperative Soil Survey
U.S.A.