LOCATION AKLAK AK
Established Series
MPS
11/2024
AKLAK SERIES
Depth class: deep to lithic bedrock
Drainage class: well drained
Parent material: gravelly loamy colluvium over residuum weathered from sandstone
Landscape: mountains
Landform: mountain slopes
Slopes: 15 to 70 percent
Mean annual precipitation: about 450 mm (17.7 in)
Mean annual air temperature: about -4 degrees C. (25 degrees F.)
Frost-free period: 70 to 85 days
TAXONOMIC CLASS: Fragmental, mixed, subgelic Typic Haplogelolls
TYPICAL PEDON: Aklak extremely gravelly silt loam in a dryas lichen alpine scrubland community on a northwest facing linear, linear backslope on a slope of 45 percent at an elevation of 931m (3055 ft)
Oa--0 to 3 cm (0 to 1 in); gravelly highly decomposed plant material; black (10YR 2/1) broken face moist, dark gray (10YR 4/1) broken face dry; many very fine, fine roots throughout and very few medium roots throughout; 30 percent gravel; 16 percent soil organic carbon; 28 percent soil organic matter; noneffervescent; moderately acid (pH 5.7); clear smooth boundary. (0 to 10 cm, 0 to 4 in thick)
A1--3 to 35 cm (1 to 14 in); extremely gravelly silt loam; very dark brown (10YR 2/2) broken face moist, dark grayish brown (10YR 4/2) broken face dry; weak fine subangular blocky parts to weak fine granular structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; many very fine and fine roots throughout; common very fine dendritic tubular pores; 5 percent cobbles, 65 percent gravel; 2 percent prominent white (7.5YR 9/1), moist, carbonate coats on bottom of rock fragments; 5 percent soil organic carbon; 9 percent soil organic matter; noneffervescent; moderately acid (pH 5.6); clear wavy boundary. (14 to 35 cm, 6 to 14in thick)
A2--35 to 45 cm (14 to 18 in); extremely gravelly silt loam; very dark brown (10YR 2/2) broken face moist, dark grayish brown (10YR 4/2) broken face dry; weak fine subangular blocky parts to weak fine granular structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; common very fine and fine roots throughout; few very fine dendritic tubular pores; 10 percent cobbles, 70 percent gravel; 5 percent soil organic carbon; 8 percent soil organic matter; noneffervescent; moderately acid (pH 5.9); gradual wavy boundary. (8 to 33 cm, 3 to 13 in thick)
C--45 to 120 cm (18 to 47 in); gravel; common medium and coarse interstitial pores; 15 percent cobbles, 80 percent gravel; clear wavy boundary. (68 to 82 cm, 27 to 32 in thick)
2R--120 to 145 cm (48 to 58 in); strongly coherent to indurated sandstone bedrock.
TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64.828001, longitude -159.4525920, datum WGS84, UTM north 7189362.64 and UTM east 478520.28, zone 4, datum WGS84.
RANGE IN CHARACTERISTICS:
Soil moisture regime: udic
Soil temperature regime: gelic
Mean annual soil temperature: -1 to 0 degrees C. (30.2 to 32 degrees F.)
Thickness of organic material: 0 to 10 cm (0 to 4 in)
Thickness of mollic epipedon: 40 to 70 cm (16 to 28 in)
Depth to fragmental layer: 22 to 78 cm (9 to 31 in)
Depth to lithic contact: 100 to 150 cm (40 to 60 in)
Oa horizon:
Hue: 7.5YR or 10YR
Value: 2 or 2.5 moist, 4 dry
Chroma: 1 or 2
Texture: highly decomposed material or its gravelly analogue
Rock fragments: 0 to 34 percent
Organic matter: 60 to 90 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
A1 horizon:
Hue: 7.5YR to 10YR
Value: 2 to 3 moist, 4 or 5 dry
Chroma: 1 to 3
Texture: silt loam or their gravelly analogues
Sand: 11 to 45 percent
Silt: 50 to 80 percent
Clay: 3 to 14 percent
Rock fragments: 35 to 80 percent
Gravels: 25 to 70 percent
Cobbles: 0 to 20percent
Organic matter: 3 to 8 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
A2 horizon:
Hue: 10YR
Value: 2 or 3 moist, 4 or 5 dry
Chroma: 1 to 3
Texture: loam, sandy loam, silt loam or their gravelly analogues
Sand: 11 to 45 percent
Silt: 21 to 80 percent
Clay: 3 to 14 percent
Rock fragments: 60 to 85 percent
Gravels: 25 to 75 percent
Cobbles: 0 to 20 percent
Organic matter: 3 to 8 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
C horizon:
In lieu of texture: gravel
Rock fragments: 90 to 100 percent
Gravels: 75 to 85 percent
Cobbles: 10 to 25 percent
2R horizon
Strongly coherent to indurated sandstone bedrock.
Some pedons have a lithic contact at depths between 90 to 165 cm (35 to 65 in).
COMPETING SERIES: none
GEOGRAPHIC SETTING:
Elevation: 300 to 850 meters (985 to 2790 feet)
Parent material: gravelly loamy colluvium over residuum weathered from sandstone
Landform: mountain slopes
Slopes: 15 to 70 percent
Mean annual precipitation: 400 to 600 mm (16 to 24 in)
Mean annual air temperature: -6 to -2 degrees C. (21 to 28 degrees F.)
Frost free period: 70 to 85 days
Aspect: 270 to 90 degrees
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Atkaktuk,
Continentaldivide, Egoosikcreek,
Imnak, Ingik,
Kikku,
Kulik,
Managaarak, and
Tui soils.
Atkaktuk soils have an umbric epipedon, have an acid reaction class, lack a surface organic horizon, and occur on similar landforms on mountainflanks, upper third
Continentaldivide soils have a lithic contact between 25 and 50 cm (10 to 20 in), have a loamy-skeletal particle size class, lack a surface organic horizon, and occur on ridges
Egoosikcreek soils have a cambic horizon, have a fine-loamy particle size class, and occur on swales
Imnak soils have a paralithic contact between 50 to 100 cm (20 to 39 in), have a cryic soil temperature regime, and occur on mountainflanks, center third and upper third
Ingik soils have paralithic contact between 50 to 100 cm (20 to 39in), have an ochric epipedon, have a loamy-skeletal particle size class, have a cryic soil temperature regime, and occur on similar landforms on mountainflanks, upper third
Kikku soils have ponding, have a reduced matrix within 50 cm, have a histic epipedon, have a fine-loamy particle size class, have free carbonates between 40 to 200 cm (16 to 79 in), and occur on on shoulders and mountainflanks, upper third
Kulik soils have a lithic contact between 50 to 100 cm (20 to 39 in), have a cambic horizon, have a loamy-particle size class, and occur on mountainflanks, center third and upper third
Managaarak soils have an ochric epipedon, have a loamy-skeletal particle size class, have an acid reaction class, and occur on similar landforms on mountainflanks, upper third
Tui soils have an ochric epipedon, have a cambic horizon, have a loamy-skeletal particle size class, have a cryic soil temperature regime, and occur on nose slopes and mountainflanks
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: well drained
Saturated Hydraulic Conductivity: very high in the Oa horizon, moderately high to high in the A1 and A2 horizons, and very high in the C horizon
Permeability: rapid to very rapid in the Oa horizon, moderate in the A1 horizon, moderate to rapid in the A2 horizon, very rapid in the C horizon
Runoff: high
USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: eightpetal mountain avens, Flavocetraria cucullata, Flavocetraria nivalis witch's hair lichen, golden asahinea lichen, cup lichen, greygreen reindeer lichen, glacier avens, globe ball lichen, whiteworm lichen
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: 28 to 103 cm (11 to 41 in)
Mollic epipedon: 3 to 45 cm (1 to 18 in) (A1 and A2 horizons)
Lithologic discontinuity: 120 to 145 cm (47 to 57 in) (2R horizon)
Lithic contact: 120 to 145 cm (47 to 57 in) (2R horizon)
ADDITIONAL DATA:
User pedon ID: 2023AK290317
National Cooperative Soil Survey
U.S.A.