LOCATION GRANDPLATEAU AK
Established Series
IRD. SAS/NDP/SCD
05/2022
GRANDPLATEAU SERIES
Landscape--hills
Landform--glacially modified hillslopes
Slope--3 to 60 percent
Parent material--volcanic ash over colluvium over residuum
Mean annual precipitation--about 3700 mm
Mean annual air temperature--about 4 degrees C
Depth class--deep
Drainage class--poorly drained
Soil moisture regime--aquic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Medial, amorphic, nonacid Typic Cryaquands
TYPICAL PEDON: Grandplateau medial very fine sandy loam on a glacially modified hillslope of 55 percent at an elevation of 109 m (When described on June 03, 2015, the soil was moist throughout.)
Oa--0 to 2 cm; highly decomposed plant material; slightly acid (pH 6.3); clear smooth boundary
A--2 to 18 cm; medial very fine sandy loam, 85 percent dark gray (10YR 4/1) dry and black (10YR 2/1) moist, 15 percent light brownish gray (10YR 6/2) dry and dark grayish brown (10YR 4/2) moist; weak coarse granular structure; soft, very friable, nonsticky and nonplastic; common very fine, medium, and coarse roots; common very fine and fine irregular pores; slightly acid (pH 6.1); clear smooth boundary
Bw1--18 to 27 cm; medial silt loam, grayish brown (10YR 5/2) dry, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine and few medium roots; common very fine and fine irregular pores; 10 percent medium dark brown (7.5YR 3/3) masses of oxidized iron and 10 percent medium dark gray (10YR 4/1) masses of reduced iron; moderately acid (pH 5.7); abrupt irregular boundary
E--27 to 43 cm; medial silt loam, 60 percent white (2.5Y 8/1) dry and gray (2.5Y 6/1) moist, 40 percent yellowish brown (10YR 5/4) dry and dark yellowish brown (10YR 3/4) moist; moderate very coarse subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few very fine and medium roots; common very fine and fine irregular pores; 10 percent medium dark brown (7.5YR 3/3) masses of oxidized iron; moderately acid (pH 5.7); clear smooth boundary
Bw2--43 to 120 cm; medial silt loam, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; moderate very coarse subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few very fine and fine roots; common very fine and fine irregular pores; 10 percent medium dark gray (10YR 4/1) masses of reduced iron and 20 percent medium yellowish red (5YR 4/6) masses of oxidized iron; 1 percent gravel, 2 percent stones, and 10 percent cobbles; moderately acid (pH 5.7); clear smooth boundary
2Bw3--120 to 130 cm; extremely cobbly silt loam, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; weak medium granular structure; slightly hard, friable, slightly sticky and nonplastic; 2 percent fine dark grayish brown (10YR 4/2) masses of reduced iron and 3 percent fine dark reddish brown (5YR 3/4) masses of oxidized iron; 5 percent gravel, 20 percent stones, and 40 percent cobbles; moderately acid (pH 5.6); clear smooth boundary
3R--130 cm; bedrock
TYPE LOCATION: Glacier Bay National Park and Preserve-Yakutat Area, Alaska; Yakutat City and Borough Census Area; latitude 59.1121320, longitude -138.2368620, datum WGS84 (coordinates determined by a GPS unit)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--1 to 7 degrees C
Soil moisture control section--usually saturated below a depth of 18 cm year round
Thickness of ash-influenced layers--36 to 55 cm
Estimated properties of layers influenced by volcanic ash
*Phosphorous retention--greater than 85 percent
*Ammonium oxalate extractable Al + 1/2 Fe--2 to 4 percent
*Volcanic glass content in 0.02- to 2.0-mm fraction--5 to 30 percent
*Volcanic ash content in 0.02- to 2.0-mm fraction--30 to 40 percent
*1/3-bar bulk density--0.6 to 0.85 g/cm3
*15-bar water retention--45 to 70 percent (undried samples), more than 15 percent (dried samples)
Particle-size control section
*Clay content--2 to 12 percent
*Total rock fragment content--0 to 14 percent
Oa horizon
Thickness--1 to 5 cm
A horizon
Hue--7.5YR or 10YR moist or dry
Value--2 to 4 moist, 4 to 6 dry
Chroma--1 to 6 moist or dry
Fine-earth texture--fine sandy loam, sandy loam, silt loam
Clay content--2 to 5 percent
Reaction (pH)--5.8 to 6.4
Thickness--5 to 17 cm
Bw1 horizon
Hue--7.5YR or 10YR moist or dry
Value--3 or 4 moist, 5 or 6 dry
Chroma--2 to 6 moist or dry
Fine-earth texture--silt loam, sandy loam, fine sandy loam
Clay content--5 to 12 percent
Reaction (pH)--5.4 to 6.4
Thickness--5 to 30 cm
E horizon
Hue--10YR to 2.5Y moist or dry
Value--6 to 8 moist or dry
Chroma--1 to 3 moist or dry
Fine-earth texture--silt loam, sandy loam, fine sandy loam
Clay content--5 to 12 percent
Reaction (pH)--5.3 to 6.4
Thickness--1 to 18 cm
Bw2 horizon
Hue--7.5YR to 2.5 Y moist or dry
Value--3 to 5 moist, 5 to 7 dry
Chroma--3 to 6 moist or dry
Fine-earth texture--silt loam, sandy loam, fine sandy loam
Clay content--5 to 12 percent
Total rock fragment content--5 to 14 percent
Gravel content--2 to 5 percent
Cobble content--3 to 10 percent
Stone content--0 to 5 percent
Reaction (pH)--5.3 to 6.4
Thickness--50 to 90 cm
2Bw3 horizon
Hue--7.5YR or 10YR moist or dry
Value--3 to 5 moist, 5 to 7 dry
Chroma--3 to 6 moist or dry
Fine-earth texture--silt loam, sandy loam, fine sandy loam
Clay content--5 to 12 percent
Total rock fragment content--60 to 75 percent
Stone content--5 to 30 percent
Cobble content--30 to 45 percent
Gravel content--5 to 35 percent
Reaction (pH)--5.3 to 6.1
Thickness--5 to 20 cm
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--35 to 200 m
Climate--cool, moist summers; mild, wet winters
Mean annual precipitation--2150 to 6400 mm
Mean annual air temperature--0 to 8 degrees C
Frost-free period--90 to 154 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Crillon--50 to 100 cm (moderately deep) to a paralithic contact; on similar landforms
Kaknau--50 to 100 cm (moderately deep) to a lithic contact; on similar landforms
Tricklake--mollic epipedon; on similar landforms
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--poorly drained
Depth to saturation in normal years--more 18 cm year round
Saturated hydraulic conductivity (Ksat)--high in A horizon, moderately high in Bw1, E, Bw2, and 2Bw3 horizons
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential natural vegetation--moss, baneberry, Sitka alder, bride's feathers, common ladyfern, devilsclub, salmonberry, Sitka spruce
DISTRIBUTION AND EXTENT: Alexander Archipelago-Gulf of Alaska Coast, Alaska; MLRA 220; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Glacier Bay National Park and Preserve-Gustavus Area, Alaska.
REMARKS:
Diagnostic horizons and other features in this pedon
*Ochric epipedon
*Cambic horizon--zones from 18 to 27 cm and 43 to 130 cm
*Aquic conditions--zone 18 to 130 cm
*Redoximorphic concentrations--zone from 18 to 130 cm
*Redoximorphic depletions that have chroma of 2 or less--zones from 18 to 27 cm and 43 to 130 cm
*Andic soil properties--zone 2 to 120 cm
*Albic material and albic horizon--zone from 27 to 43 cm
*Depth to lithic contact--130 cm
*Depth to lithologic discontinuity--120 cm
*Particle-size control section--zone from 2 to 102 cm
National Cooperative Soil Survey
U.S.A.