LOCATION DISTIN AK

Established Series
Rev. MHC/DLM
02/2022

DISTIN SERIES

Depth class: shallow to deep to permafrost
Drainage class: poorly drained
Landforms: circles on stream terraces, circles on till plains
Parent material: silty eolian deposits over gravelly cryoturbate
Elevation: 427 to 512 feet
Slope: 0 to 5 percent
Annual precipitation: 23 to 24 inches
Annual temperature: 24.8 degrees F
Frost-free period: 60 to 90 days

TAXONOMIC CLASS:

TYPICAL PEDON: Distin silt loam - on a slope of 0 percent under ericaceous shrub/lichen dwarf scrub. (All colors are for moist soil). This profile is separated into two parts, the first part is in an intermound area troughs between circles; the second part is from within the convex circle center or boil. Mound-intermound topography consists of about 80 percent intermounds and 20 percent mounds. One complete cycle of mound-intermound occurs about every 4 meters.

Part I -- eighty percent in convex circle centers

Oe--0 to 1 inch; very dark brown (10YR 2/2) moderately decomposed plant material; many very fine and fine and few medium roots; 2 percent gravel; very strongly acid (pH 4.6); abrupt smooth boundary.

A--1 to 2 inches; very dark brown (10YR 2/2) silt loam; very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; 2 percent gravel; very strongly acid (pH 4.9); clear smooth boundary.

2Bw/Cjj--2 to 14 inches; olive brown (2.5Y 4/4) and dark olive gray (5Y 3/2) gravelly loam; friable, nonsticky and nonplastic; few very fine and fine roots; 15 percent gravel; 2 percent cobble; 5 mm dark yellowish brown (10YR 4/4) high chroma redox concentrations (approximately 10 percent of horizon); strongly acid (pH 5.2); gradual smooth boundary.

2C--14 to 60 inches; dark olive gray (5Y 3/2) gravelly loam; friable, nonsticky and nonplastic; 15 percent gravel; 2 percent cobble; moderately acid (pH 5.7).

2Cf--60 to 72 inches; dark olive gray (5Y 3/2) frozen gravelly loam; friable, nonsticky and nonplastic; 15 percent gravel; 2 percent cobble; moderately acid (pH 5.7).

Part II - 20% in concave circle troughs

Oi--0 to 8 inches; black (7.5YR 2.5/1) peat; many very fine, fine, medium, and few coarse roots; very strongly acid (pH 4.6); clear broken boundary.

A--8 to 10 inches; very dark brown (10YR 2/2) mucky silt loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; many very fine, fine, medium, and few coarse roots; very strongly acid (pH 4.9); clear wavy boundary.

2Cg1--10 to 19 inches; dark gray (5Y 4/1) loam; massive; friable, nonsticky and nonplastic; common very fine and fine and common medium roots; 5 percent gravel; 2 mm yellowish red (5YR 4/6) high chroma redox concentrations (approximately 20 percent of horizon); very strongly acid (pH 5.0); abrupt wavy boundary.

2Cg2--19 to 22 inches; olive brown (2.5Y 4/3) gravelly sandy loam; massive; friable, nonsticky and nonplastic; few very fine and fine roots; 15 percent gravel; 1 mm strong brown (7.5YR 4/6) high chroma redox concentrations (approximately 10 percent of horizon); 1 mm gray (2.5Y 5/1) low chroma redox depletions (approximately 10 percent of horizon); strongly acid (pH 5.5); gradual wavy boundary.

2Cgf--22 to 60 inches; dark grayish brown (2.5Y 4/2) permanently frozen gravelly sandy loam; 25 percent gravel, 5 percent cobbles; 1 mm strong brown (7.5YR 4/6) high chroma redox concentrations (approximately 10 percent of horizon); 1 mm gray (2.5Y 5/1) low chroma redox depletions (approximately 15 percent of horizon); moderately acid (pH 5.7); clear wavy boundary.

TYPE LOCATION: Steward River Training Site, Alaska; UTM coordinates: Zone 3 Easting 477573, Northing 7186504

RANGE IN CHARACTERISTICS:

Range in Characteristics
Soil moisture class: aquic
Average annual soil temperature: about 30 degrees F.
Mean summer soil temperature: about 35 degrees F.
Depth to contrasting textural stratification: 1 to 3 inches
Depth to permafrost: 47 to 60 inches or more

Oi and Oe horizons:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 or 2
Texture: slightly decomposed plant material, moderately decomposed plant material
Organic matter content: 65 to 90 percent
Rock fragments: 0 to 5 percent rounded indurated gravel
Reaction: extremely acid to very strongly acid

A horizon:
Value: 2 or 3
Chroma: 2 or 3
Texture: mucky silt loam; silt loam
Clay content: 0 to 10 percent
Silt content: 55 to 75 percent
Sand content: 15 to 35 percent
Organic matter content: 8 to 12 percent
Rock fragments: 0 to 5 percent rounded indurated gravel
Reaction: extremely acid to very strongly acid

2Bw/Cjj horizon, Bw part:
Hue: 10YR or 2.5Y
2Bw/Cjj horizon, Cjj part:
Hue: 2.5Y or 5Y
Value: 3 or 4
Chroma: 1 or 2
Texture: cobbly sandy loam, very cobbly sandy loam, gravelly loam
Clay content: 5 to 15 percent
Silt content: 10 to 45 percent
Sand content: 40 to 75 percent
Organic matter content: 0 to 1 percent
Rock fragments: 0 to 30 percent subangular very strongly cemented gravel, 0 to 5 percent subangular very strongly cemented cobbles
Reaction: very strongly acid to slightly acid

2C horizon:
Hue: 2.5Y or 5Y
Value: 3 or 4
Chroma: 1 to 3
Texture: cobbly sandy loam, very cobbly sandy loam, gravelly loam
Clay content: 5 to 15 percent
Silt content: 10 to 45 percent
Sand content: 40 to 75 percent
Rock fragments: 0 to 30 percent subangular very strongly cemented gravel, 0 to 5 percent subangular very strongly cemented cobbles
Reaction: very strongly acid to slightly acid

2Cf horizon (when present):
Hue: 2.5Y or 5Y
Value: 3 or 4
Chroma: 1 to 3
Texture: cobbly sandy loam, very cobbly sandy loam, gravelly loam
Clay content: 5 to 15 percent
Silt content: 10 to 45 percent
Sand content: 40 to 75 percent
Rock fragments: 0 to 30 percent subangular very strongly cemented gravel, 0 to 5 percent subangular very strongly cemented cobbles
Reaction: very strongly acid to slightly acid

COMPETING SERIES: This is the Frostcircle series Frostcircle have a mean summer soil temperature greater than 36 degrees F.

GEOGRAPHIC SETTING:
Landforms: circles on stream terraces, circles on till plains
Parent material: silty eolian deposits over gravelly cryoturbate
Elevation: 427 to 512 feet
Slope: 0 to 5 percent
Annual precipitation: 23 to 24 inches
Annual temperature: 24.8 degrees F
Frost-free period: 60 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS: These include Cassiterite, Dirrant, and Tisuk soils. Cassiterite soils are somewhat poorly drained, very deep, and occur on flood plains. Dirrant soils are very poorly drained, shallow to permafrost, and occur on till plains. Tisuk soils are well drained, very deep, and occur on mountains, hill, and till plains.

DRAINAGE AND PERMEABILITY: Poorly drained, negligible or low runoff. Saturated hydraulic conductivity is moderately high to high above the permafrost and very low in the permafrost.

USE AND VEGETATION: Used for military use and wildlife habitat. Native vegetation is ericaceous shrub/lichen dwarf scrub.

DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hill-Southern Seaward Peninsula Highlands, Alaska. The series is of small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES ESTABLISHED: Steward River Training Site, Alaska, 2005

REMARKS: Diagnostic features and horizons recognized in this profile include:
Depth to permafrost: 60 to 72 inches. (2Cf horizon)
Cambic horizon: 2 to 14 inches. (2Bw/Cjj horizon)
Cryoturbation: 2 to 14 inches. (2Bw/Cjj horizon)
Coarse-loamy particle size control section: 10 to 40 inches
Temperature regime: pergelic
Moisture regime: aquic.

ADDITIONAL DATA:

National Cooperative Soil Survey
U.S.A.