LOCATION IKSRUKKAA               AK

Tentative Series
SWD/CBB
10/2024

IKSRUKKAA SERIES

Depth class: moderately deep to bedrock, paralithic
Drainage class: well drained
Parent material: gravelly loamy colluvium over residuum weathered from slate
Landscape: hills
Landform: hillslopes
Slopes: 10 to 45 percent
Mean annual precipitation: about 450 mm (18 in)
Mean annual air temperature: about -3 degrees C. (27 degrees F.)
Frost-free period: 75 to 90 days

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Folistic Dystrocryepts

TYPICAL PEDON: Iksrukkaa very cobbly silt loam in an alder community on a northwest facing convex, linear backslope on a slope of 30 percent at an elevation of 271 m (890 ft)

Oe--0 to 18 cm (0 to 7 in); moderately decomposed plant material, very dark brown (10YR 2/2) moist, dark grayish brown (10YR 4/2) dry; very friable; very strongly acid (pH 4.7); abrupt smooth boundary. (15 to 20 cm, 6 to 8 in thick)

C--18 to 60 cm (7 to 24 in); very cobbly silt loam, brown (10YR 4/3) moist, pale brown (10YR 6/3) dry; structureless massive; very friable, soft, nonsticky, nonplastic; nonfluid; 20 percent gravel, 35 percent cobbles; strongly acid (pH 5.4); clear smooth boundary. (10 to 75 cm, 4 to 30 in thick)

2Cr--60 to 85 cm (24 to 34 in); extremely weakly to moderately coherent slate bedrock (25 to 95 cm, 10 to 37 in thick)

TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64 degrees 7 minutes 22.64 seconds north, longitude 160 degrees 15 minutes 55.48 seconds west, datum WGS84, UTM north 7111327.97 and UTM east 561618.77, zone 57W, datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: udic
Soil temperature regime: cryic
Mean annual soil temperature: 0 to 3 degrees C. (32 to 37 degrees F.)
Thickness of organic material: 15 to 20 cm (6 to 8 in)
Thickness of folistic epipedon: 15 to 20 cm (6 to 8 in)
Depth to lithologic discontinuity: 50 to 100 cm (20 to 40 in)
Depth to paralithic contact: 50 to 100 cm (20 to 40 in)

Oe horizon:
Hue: 10YR or 7.5YR
Value: 2 to 2.5 moist, 4 to 5 dry
Chroma: 1 to 2
Texture: moderately decomposed plant material
Organic matter: 60 to 90 percent
Reaction class: extremely acid to very strongly acid (pH 3.5 to 5.0)

C horizon:
Hue: 10YR or 2.5Y
Value: 3 to 5 moist, 5 to 7 dry
Chroma: 2 to 4
Texture: silt loam, loam, or its cobbly or gravelly analogues
Sand: 15 to 45 percent
Silt: 45 to 80 percent
Clay: 2 to 11 percent
Rock fragments: 35 to 75 percent
Gravels: 15 to 65 percent
Cobbles: 0 to 40 percent
Organic matter: 0.2 to 3 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.5)

2Cr horizon

Some pedons have a paralithic contact at depths from 38 to 114 cm (15 to 45 in).

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 200 to 450 meters (655 to 1480 feet)
Parent material: gravelly loamy colluvium over residuum weathered from slate
Landform: hillslopes
Slopes: 10 to 45 percent
Mean annual precipitation: 400 to 500 mm (16 to 20 in)
Mean annual air temperature: -5 to -1 degrees C. (23 to 30 degrees F.)
Frost free period: 75 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ugguktuk, Tui, Sikuruk, Kimigaak, Siksrik, and Amigak soils.
Ugguktuk soils are somewhat poorly drained with aquic conditions between 37 to 90 cm (15 to 35 in) and occur on broad ridges on summit positions.
Tui soils have a cambic horizon between 6 to 44 cm (2 to 17 in) and occur on similar landforms on nose slopes.
Sikuruk soils have permafrost at depths below 80 cm (31 in), aquic conditions at the surface, and occur on saddles of hills.
Kimigaak soils have andic soil properties at depths between 3 to 16 cm (1 to 6 in) and occur on ridges of hills.
Siksrik soils do not have paralithic contact within 200 cm (80 in) and occur on footslopes and backslopes of hillslopes.
Amigak soils have aquic conditions at the soil surface and a cambic horizon at depths between 27 and 95 cm (11 to 37 in) and occur on side slopes of backslopes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: well drained
Saturated Hydraulic Conductivity: high to very high in the Oe horizon and moderately high in the C horizon
Permeability: very rapid in the Oe horizon and moderate in the C horizon
Runoff: high

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: Siberian alder, dwarf birch, bog blueberry, black crowberry, marsh Labrador tea, Bigelow's sedge, alpine bearbery, polytrichum moss, lingonberry, Beauverd spirea, fireweed, and splendid feather moss.

DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hills-Southern Seward Peninsula Highlands. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Wasilla, Alaska

SERIES ESTABLISHED: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey, Alaska, 2024.

REMARKS: Diagnostic features and horizons recognized in this profile include:

Particle-size control section: 43 to 60 cm (17 to 24 in)

Folistic epipedon: 0 to 18 cm (6 to 8 in) (Oe horizon)

Hemic soil materials: 0 to 18 cm (6 to 8 in) (Oe horizon)

Lithologic discontinuity: 60 to 85 cm (24 to 33 in) (2Cr horizon)

Paralithic contact: 60 to 85 cm (24 to 33 in) (2Cr horizon)

ADDITIONAL DATA:

User pedon ID: 2021AK180867

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National Cooperative Soil Survey
U.S.A.