LOCATION SHEEPSKULL              WA

Established Series
IRD. SMB/PHR/MPR
07/2017

SHEEPSKULL SERIES

Landscape--Cascade Mountains
Landform--lahars, moraines, outwash terraces, glacial valley floors
Slope--15 to 100 percent
Parent material--glacial till and lahar sediment over andesite
Mean annual precipitation--about 2200 mm
Mean annual air temperature--about 3 degrees C
Depth class--moderately deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic

TAXONOMIC CLASS: Ashy-skeletal, glassy Typic Vitricryands

TYPICAL PEDON: Sheepskull very gravelly ashy sandy loam on a south-facing forested moraine with a slope of 55 percent and at an elevation of 1435 m (When described on July 11, 2013, the soil was moist throughout.)

Oi--0 to 2 cm; slightly decomposed plant material; very strongly acid (pH 4.5); clear wavy boundary

A1--2 to 30 cm; very gravelly ashy sandy loam, dark gray (10YR 4/1) dry, black (10YR 2/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine, common fine and medium, and few coarse roots; common very fine and fine interstitial pores; 25 percent fine andesite gravel, 15 percent medium and coarse andesite gravel, and 15 percent andesite cobbles; moderately acid (pH 5.7); clear wavy boundary

A2--30 to 64 cm; extremely cobbly ashy sandy loam, dark gray (10YR 4/1) dry, black (10YR 2/1) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and few fine and medium roots; common very fine and fine interstitial pores; 15 percent fine andesite gravel, 20 percent medium and coarse andesite gravel, 20 percent andesite cobbles, and 5 percent andesite stones; moderately acid (pH 5.7); abrupt irregular boundary

2R--64 cm; andesite

TYPE LOCATION: Pierce County, Washington, south of the South Puyallup River, along the Wonderland Trail between Emerald Ridge and South Puyallup River Campground in Mount Rainier National Park; about 275 m south and 15 m east of the northwest corner of section 6, T. 15 N., R. 8 E., Willamette Meridian; Mount Rainier West, Washington, U.S. Geological Survey quadrangle; latitude 46.817974 degrees north, longitude -121.855211 degrees west, datum WGS 84 (coordinates determined with a GPS)

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 6 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October
Depth to lithic contact--50 to 100 cm (moderately deep)

All mineral horizons
*Reaction--5.1 to 6.0
*Organic carbon content--less than 0.6 percent
*Volcanic glass content--50 to 75 percent
*Ammonium oxalate Al plus 1/2 Fe--greater than 0.4 percent

Particle-size control section
*Clay content--1 to 7 percent
*Rock fragment content--35 to 75 percent total, including 15 to 50 percent gravel, 5 to 35 percent cobbles, 0 to 10 percent stones, and 0 to 10 percent boulders

Oi horizon
*Thickness--0 to 5 cm

A1 horizon
*Hue--10YR, 7.5YR
*Value--1 to 3 moist, 3 to 5 dry
*Chroma--1 to 3 moist or dry
*Fine-earth texture--ashy sandy loam, ashy loamy sand
*Thickness--25 to 40 cm

A2 horizon
*Hue--10YR, 7.5YR
*Value--2.5 to 5 moist, 4 to 7 dry
*Chroma--1 to 4 moist or dry
*Fine-earth texture--ashy sandy loam, ashy loamy sand, ashy coarse sandy loam
*Thickness--25 to 60 cm

COMPETING SERIES:
Glacierisland--greater than 150 cm deep to lithic contact (very deep)

GEOGRAPHIC SETTING:
Elevation--1000 to 2000 m
Climate--cool, dry summers; cold, wet winters
Mean annual precipitation--1700 to 2800 mm
Mean annual air temperature--2 to 5 degrees C
Frost-free period--30 to 60 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Sluiskin--lithic contact within 50 cm of soil surface (shallow); associated with areas that have bedrock near surface
Glacierisland--greater than 150 cm to lithic contact; in areas of deeper glacial till and lahar sediment
Wonderland--aquic conditions with an upper limit of 25 cm from soil surface; in gentler sloping positions that receive runoff

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturated hydraulic conductivity (Ksat)--high, very high

USE AND VEGETATION:
Use--wildlife habitat, recreation
Potential natural vegetation--subalpine fir, mountain hemlock, Pacific silver fir, noble fir, Engelmann spruce, Sitka alder, vine maple, thimbleberry, Oregon oxalis, deer fern, western swordfern, oakfern, twinflower

DISTRIBUTION AND EXTENT: Central Cascade Mountains, Washington; MLRA 3; small extent

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

SERIES ESTABLISHED: Mount Rainier National Park, Pierce County, Washington; 2014; name from Sheepskull Gap in Mount Rainier National Park

REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 2 to 64 cm
*Ochric epipedon
*Cambic horizon--zone from 2 to 64 cm
*Andic soil properties--zone from 2 to 64 cm
*Volcanic glass--zone from 2 to 64 cm
*Depth to lithic contact--64 cm

3/2017--This official series description was updated according to SSR1 Technical Note 11--Content and Format of Official Series Descriptions (revised 12/2015). Most of the changes were in formatting; no major technical changes were made.

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National Cooperative Soil Survey
U.S.A.