LOCATION IYYAGRIK AK
Tentative Series
MPS
10/2024
IYYAGRIK SERIES
Depth class: deep to lithic bedrock
Drainage class: well drained
Parent material: gravelly loamy colluvium over gravelly loamy residuum weathered from graywacke
Landscape: mountains
Landform: mountain slopes
Slopes: 20 to 70 percent
Mean annual precipitation: about 500 mm (20 in)
Mean annual air temperature: about -4 degrees C. (40 degrees F.)
Frost-free period: 70 to 90 days
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Pachic Haplocryolls
TYPICAL PEDON: Iyyagrik very cobbly silt loam in a dryas lichen scrubland community on a southeast facing linear, convex backslope on a slope of 51 percent at an elevation of 611m (2005 ft)
Oe--0 to 6 cm (0 to 2 in); moderately decomposed plant material; black (10YR 2/1) broken face moist, very dark grayish brown (10YR 3/2) broken face dry; many very fine and fine, and moderately few medium roots throughout; slightly acid (pH 6.2); abrupt smooth boundary. (1 to 10 cm, 0.5 to 4 in thick)
A--6 to 19 cm (2 to 8 in); very cobbly silt loam; very dark brown (10YR 2/2) broken face moist, dark yellowish brown (10YR 4/4) broken face dry; weak fine granular structure; very friable, soft, nonsticky, nonplastic; nonsmeary; many very fine and fine roots throughout; common very fine dendritic tubular pores; 20 percent gravel, 35 percent cobbles; noneffervescent; moderately acid (pH 6.0); clear smooth boundary. (8 to 30 cm, 3 to 12 in thick)
Bw1--19 to 38 cm (8 to 15 in); very gravelly silt loam; very dark grayish brown (10YR 3/2) broken face moist, brown (10YR 4/3) broken face dry; weak medium subangular blocky structure; very friable, soft, nonsticky, nonplastic; nonsmeary; moderately few very fine and common fine roots throughout; few very fine dendritic tubular pores; 10 percent cobbles, 30 percent gravel; noneffervescent; slightly acid (pH 6.2); clear smooth boundary. (10 to 22 cm, 4 to 9 in thick)
Bw2--38 to 79 cm (15 to 31 in); very gravelly silt loam; very dark grayish brown (10YR 3/2) broken face moist, brown (10YR 4/3) broken face dry; weak medium subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; moderately few very fine roots and common fine roots throughout; few very fine irregular pores; 15 percent cobbles, 40 percent gravel; noneffervescent; slightly acid (pH 6.2); clear smooth boundary. (25 to 45 cm, 10 to 18 in thick)
Bw3--79 to 100 cm (31 to 39 in); extremely gravelly silt loam; very dark grayish brown (10YR 3/2) broken face moist, brown (10YR 4/3) broken face dry; weak medium subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; moderately few very fine roots throughout; few very fine irregular pores; 21 percent cobbles, 40 percent gravel; noneffervescent; slightly acid (pH 6.3); clear smooth boundary. (10 to 24 cm, 4 to 9 in thick)
2C--100 to 135 cm (39 to 53 in); extremely gravelly silt loam; dark yellowish brown (10YR 3/4) moist, yellowish brown (10YR 5/4) dry; massive; friable, slightly hard, nonsticky, nonplastic; nonsmeary; few very fine irregular pores; 30 percent cobbles, 50 percent gravel; noneffervescent; slightly acid (pH 6.5); gradual irregular boundary. (20 to 60 cm, 8 to 24 in thick)
2R--135 to 160 cm (53 to 63 in); strongly coherent to indurated greywacke bedrock.
TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64.5921475, longitude -159.5130975, datum WGS84, UTM north 7163100.78 and UTM east 475435.97, zone 4, 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: 1 to 10 cm (0.5 to 4 in)
Thickness of mollic epipedon: 53 to 121 cm (21 to 48 in)
Depth to lithic contact: 100 to 150 cm (39 to 60 in)
Oe horizon:
Hue: 5YR, 7.5YR or 10YR
Value: 2 to 2.5 moist, 4 dry
Chroma: 1 or 2
Texture: moderately decomposed material
Organic matter: 60 to 90 percent
Reaction class: very strongly acid to slightly acid (pH 4.5 to 6.5)
A horizon:
Hue: 7.5YR or 10YR
Value: 2 to 3 moist, 4 or 5 dry
Chroma: 1 or 2
Texture: silt loam or their gravelly or cobbly analogues
Sand: 10 to 47 percent
Silt: 50 to 80 percent
Clay: 3 to 11 percent
Rock fragments: 20 to 59 percent
Gravels: 15 to 35 percent
Cobbles: 5 to 40 percent
Organic matter: 2 to 8 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
Bw1 horizon:
Hue: 7.5YR or 10YR
Value: 2 to 3 moist, 4 or 5 dry
Chroma: 1 to 3
Texture: silt loam, sandy loam or their gravelly or cobbly analogues
Sand: 25 to 60 percent
Silt: 30 to 72 percent
Clay: 3 to 10 percent
Rock fragments: 35 to 59 percent
Gravels: 25 to 40 percent
Cobbles: 8 to 30 percent
Organic matter: 2 to 8 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
Bw2 horizon:
Hue: 10YR
Value: 2 or 3 moist, 4 or 5 dry
Chroma: 1 to 3
Texture: silt loam, very fine sandy loam or their gravelly analogues
Sand: 25 to 65 percent
Silt: 23 to 71 percent
Clay: 4 to 12 percent
Rock fragments: 40 to 65 percent
Gravels: 30 to 45 percent
Cobbles: 10 to 20 percent
Organic matter: 2 to 8 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
Bw3 horizon:
Hue: 10YR
Value: 2 or 3 moist, 4 or 5 dry
Chroma: 1 to 3
Texture: silt loam, sandy loam or their gravelly or cobbly analogues
Sand: 25 to 70 percent
Silt: 22 to 70 percent
Clay: 2 to 8 percent
Rock fragments: 60 to 75 percent
Gravels: 25 to 50 percent
Cobbles: 15 to 30 percent
Organic matter: 2 to 8 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
2C horizon:
Hue: 10YR or 2.5Y
Value: 3 or 4 moist, 5 or 6 dry
Chroma: 2 to 4
Texture: silt loam, sandy loam or their gravelly or cobbly analogues
Sand: 35 to 70 percent
Silt: 20 to 63 percent
Clay: 2 to 10 percent
Rock fragments: 60 to 85 percent
Gravels: 30 to 70 percent
Cobbles: 15 to 35 percent
Organic matter: 0.4 to 3 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
2R horizon
strongly coherent to indurated greywacke bedrock.
Some pedons have a paralithic contact at depths between 85 to 100 cm (34 to 40 in), or mollic epipedons with thicknesses from 30 to 40 cm.
COMPETING SERIES : These are the Tagluk (AK), Behanco, Dressel, and Gateview (CO), Behanin (CO, UT), Povey (CO, ID), Lund (ID), Hobacker and Mundos (ID, WY), Nagisty (ID, UT), Boatman and Marcetta (MT), Harcany (NV, OR), Baconcamp (OR), Croesus (NV), Parkcity (UT), and Hapgood (CA, CO, ID, MT, NV, OR) series.
Tagluk soils lack a lithic contact within 200 cm (80 in), have a folistic epipedon
Behanco soils have an albic horizon, have clay films, have a cambic horizon
Dressel soils lack lithic contact within 200 cm (80 in), have an albic horizon, have a cambic horizon
Gateview soils lack lithic contact within 200 cm (80 in).
Behanin soils lack lithic contact within 200 cm (80 in), have a cambic horizon
Povey soils have a xeric soil moisture regime, have a cambic horizon
Lund soils lack lithic contact within 200 cm (80 in), have a calcic horizon below 100 cm (39 in)
Hobacker soils lack lithic contact within 200 cm (80 in), have a cambic horizon, and have a calcic horizon below 15 cm
Mundos soils lack lithic contact within 200 cm (80 in), have calcareous material below 25 cm (10 in), and have a cambic horizon
Nagisty soils have lithic contact at depths between 50 to 100 cm (20 to 40 in), have clay ranging from 18 to 27 percent in the substratum
Boatman soils lack lithic contact within 200 cm (80 in), have clay ranging from 18 to 27 percent in the substratum
Marcetta soils lack lithic contact within 200 cm (80 in), have an albic horizon, have an ustic soil moisture regime
Harcany soils lack lithic contact within 200 cm (80 in), and have a xeric soil moisture regime
Baconcamp soils have lithic contact at depths between 50 to 100 cm (20 to 40 in), have a xeric soil moisture regime
Croesus soils have lithic contact at depths between 50 to 100 cm (20 to 40 in), have a xeric soil moisture regime
Parkcity soils lack lithic contact within 200 cm (80in), have surface rock fragments
Hapgood soils have a xeric soil moisture regime
GEOGRAPHIC SETTING:
Elevation: 200 to 900 meters (655 to 2955 feet)
Parent material: gravelly loamy colluvium over gravelly loamy residuum weathered from graywacke
Landform: mountain slopes
Slopes: 20 to 70 percent
Mean annual precipitation: 400 to 600 mm (16 to 24 in)
Mean annual air temperature: -6 to -1 degrees C. (21 to 30 degrees F.)
Frost free period: 70 to 90 days
Aspect: 90 to 270 degrees
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Continentaldivide,
Debauch, Ingik, Isimnjaatuk,
Iyagak, Kanik, Managaarak,
Myoukchuk, Nautchiak, Nunanjiak, Savik, Siku, Tui, and Tumi soils.
Continentaldivide soils have a lithic contact at depths between 25 to 50 cm (10 to 20 in), have a gelic soil temperature regime, and occur on ridges of mountains
Debauch soils have a paralithic contact at depths between 25 to 50 cm (10 to 20 in), have an ochric epipedon, have a gelic soil temperature regime, and occur on ridges of mountains
Ingik soils have a paralithic contact at depths between 50 to 100 cm (20 to 40 in), have an ochric epipedon, and occur on similar landforms on mountainflanks, upper third
Isimnjaatuk soils have a paralithic contact at depths between 100 to 150 cm (40 to 60 in), have an ochric epipedon, have a cambic horizon, have a gelic soil temperature regime
Iyagak soils have a fragmental layer starting at depths between 25 to 59 cm (10 to 23 in), have an ochric epipedon, have a cambic horizon, have a fragmental particle size class, and occur on swales and mountainflanks, center third
Kanik soils have a lithic contact at depths between 100 to 150 cm (40 to 60 in), have a fragmental layer starting at depths between 66 to 100 cm (26 to 40 in), have an ochric epipedon, have a gelic soil temperature regime, and occur on mountainflanks, upper and center thirds
Managaarak soils have a lithic contact at depths between 100 to 150 cm (40 to 60 in), have a fragmental layer starting at depths between 41 to 93 cm (16 to 37 in), have an ochric epipedon, have a gelic soil temperature regime, have an acid reaction class, and occur on similar landforms on mountainflanks, upper third
Myoukchuk soils have a lithic contact at depths between 100 to 150 cm (40 to 60 in), have a fragmental layer starting at depths between 4 to 16 cm (2 to 6 in), have an ochric epipedon, and occur on valley sides and mountain flanks, upper thirds
Nautchiak soils lack lithic contact within 200 cm (80 in), have an ochric epipedon, have a cambic horizon, clay ranges up to 25 percent in the substratum, and occur on drainageways and swales on mountain slopes
Nunanjiak soils have a paralithic contact at depths between 100 to 150 cm (40 to 60 in), have andic soil properties, have a folistic epipedon, have an umbric epipedon, can have spodic materials, have a cambic horizon, have a medial over loamy-skeletal particle size class, and occur on head slopes and mountainflanks, center third
Savik soils have a paralithic contact at depths between 25 to 50 cm (10 to 20 in), have a fragmental layer starting at depths between 13 to 39 cm (5 to 15 in), have an umbric epipedon, have a gelic soil temperature regime, have a fragmental particle size class, and occur on nose slopes on knife ridges and mountainflanks, upper third on knife ridges
Siku soils have aquic conditions starting between 0 and 25 cm (0 to 10 in), have a reduced matrix within 25 cm (10 in), have a folistic epipedon, have a cambic horizon, have a gelic soil temperature regime, have an acid reaction class, and occur on mountainflanks, upper, center and lower thirds
Tui soils lack lithic contact within 200 cm (80 in), have an ochric epipedon, have a cambic horizon, and occur on nose slopes and mountainflanks
Tumi soils have lithic contact at depths between 50 to 100 cm (20 to 40 in), have a fragmental layer starting at depths between 33 to 141 cm (13 to 56 in), have an ochric epipedon, have a cambic horizon, have a loamy-skeletal over fragmental particle size class, and occur on mountainflanks, upper, center and lower thirds
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: well drained
Saturated Hydraulic Conductivity: very high in the Oe horizon, moderately high to high in the A, Bw1, Bw2, Bw3, and 2C horizons
Permeability: rapid to very rapid in the Oe horizon, moderate in the A horizon, moderate to moderately rapid in the Bw2 horizon, and moderate to rapid in the Bw1, Bw2, and 2C horizons
Runoff: high
USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: eightpetal mountain-avens, alpine bearberry, bog blueberry, black crowberry, rhytidium moss, Flavocetraria cucullata lingonberry, star reindeer lichen, greygreen reindeer lichen, Altai fescue, Fries' pussytoes, alpine sweetvetch, cetraria lichen, snow lichen, reindeer lichen, purple reedgrass
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: 31 to 106 cm (12 to 42 in)
Mollic epipedon: 6 to 100 cm (2 to 39 in) (A, Bw1, Bw2, and Bw3 horizons)
Lithologic discontinuity: 100 to 160 cm (39 to 63 in) (2C and 2R horizons)
Lithic contact: 135 to 160 cm (53 to 63 in) (2R horizon)
ADDITIONAL DATA:
User pedon ID: 2021AK290720
National Cooperative Soil Survey
U.S.A.