LOCATION THIRDLAKE AK

Established Series
SDB/MJS
08/2025

THIRDLAKE SERIES

Depth class: very deep
Drainage class: poorly drained
Parent material: organic material over silty loess over sandy and gravelly glaciolacustrine deposits
Landscape: outwash plains
Landform: glacial lakes (relict), flats, and outwash plains
Slope: 0 to 10 percent
Mean annual precipitation: about 600 mm (24 in)
Mean annual air temperature: about -3 degrees C (27 F)
Frost-free period: 60 to 103 days

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid Typic Cryaquents

TYPICAL PEDON: Thirdlake muck in a dwarf birch black spruce community on a relict glacial lake on a slope of 1 percent at an elevation of 694m (2275 ft).

Oi--0 to 7 cm (0 to 3 in); peat, dark brown (7.5YR 3/2) moist; many very fine, fine, and common medium roots throughout; strongly acid (pH 5.2); clear smooth boundary (3 to 8 cm, 1 to 3 in)

Oa--7 to 16 cm (3 to 6 in); muck, black (10YR 2/1) moist; many very fine, fine, and few medium roots throughout; slightly acid (pH 6.1); clear smooth boundary (3 to 10 cm, 1 to 4 in)

A--16 to 23 cm (6 to 9 in); very cobbly silt loam, very dark gray (10YR 3/1) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky, slightly plastic; nonsmeary; many very fine and common fine roots throughout; very fine and fine pores; 20 percent cobbles and 30 percent gravel by volume; slightly acid (pH 6.5); clear smooth boundary (0 to 9 in, 0 to 4 in)

A/Cg--23 to 32 cm (9 to 13 in); gravelly loamy sand, very fine sandy loam, 70 percent very dark gray (10YR 3/1) and 30 percent dark gray (2.5Y 4/1) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky, nonplastic; nonsmeary; common very fine and few fine roots throughout; very fine and fine pores; 25 percent gravel by volume; noneffervescent; strongly alkaline (pH 8.6); clear broken boundary (5 to 10 cm, 2 to 4 in)

Cg--32 to 150 cm (13 to 59 in); gravelly sandy loam, 75 percent gray (2.5Y 5/1) and 25 percent dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky, nonplastic; nonsmeary; few very fine roots at top of horizon; fine pores; 25 percent fine noncoherent cemented gray (2.5Y 5/1) masses of oxidized iron infused into matrix adjacent to pores and 75 percent coarse noncoherent cemented dark yellowish brown (10YR 4/4) reduced matrix throughout; 20 percent gravel by volume; noneffervescent; strongly alkaline (pH 8.7). (113 to 139 cm, 44 to 55 in)

TYPE LOCATION: North Copper River Soil Survey Area, Alaska; latitude 61.60848, longitude -145.13408, UTM 6831983.30 north and UTM 598974.02 east, zone 6, Datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: aquic
Soil temperature regime: cryic
Mean annual soil temperature: 1 to 5 degrees C. (34 to 41 degrees F)
Thickness of organic material: 6 to 18 cm (2 to 7 in)
Thickness of ochric epipedon: 6 to 27 cm (2 to 11 in)
Depth to redoximorphic concentrations: 6 to 27 cm (2 to 11 in)
Depth to reduced matrix: 6 to 27 cm (2 to 11 in)
Depth to aquic conditions: 6 to 27 cm (2 to 11 in)

Oi, Oe, Oa horizons:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 to 3
Texture: Peat, mucky-peat, muck
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
Chroma: 1 to 3
Texture: loam, very gravelly silt loam, cobbly silt loam
Sand: 18 to 48 percent
Silt: 48 to 78 percent
Clay: 4 to 9 percent
Rock fragments: 10 to 57 percent
Gravels: 8 to 32 percent
Cobbles: 2 to 25 percent
Organic matter: 1 to 7 percent
Reaction class: slightly acid to neutral (pH 6.1 to 7.3)

A/C horizon:
Matrix color (A horizon material) has a hue of 7.5YR or 10YR, Value of 2 to 3, and a Chroma of 1 to 3
Reduced material (Cg horizon material) has a hue of 2.5Y or 5 Y, value of 4 or 5, and a chroma of 1 or 2.
Texture: gravelly loam, gravelly fine sandy loam, gravelly very fine sandy loam, fine sandy loam
Sand: 18 to 48 percent
Silt: 18 to 46 percent
Clay: 9 to 15 percent
Rock fragments: 16 to 28 percent
Gravels: 16 to 28 percent
Organic matter: 0.5 to 1.5 percent
Reaction class: moderately alkaline to strongly alkaline (pH 7.9 to 9)

Cg horizon:
Hue: 10YR or 2.5Y
Value: 4 to 5
Chroma: 1 to 2
Texture: loam, loamy very fine sand, gravelly sandy loam
Sand: 39 to 72 percent
Silt: 15 to 48 percent
Clay: 6 to 13 percent
Rock fragments: 2 to 22 percent
Gravels: 2 to 22 percent
Organic matter: 0.05 to 0.2 percent
Reaction class: moderately alkaline to strongly alkaline (pH 7.9 to 9)

COMPETING SERIES: These are the Aquatna, Beluga, Moose River, Noonku, Ottercreek, and Susivar soils.
Aquatna, Beluga, Moose River, and Noonku soils are very poorly drained.
Ottercreek soils lack an A horizon
Susivar soils are somewhat poorly drained and are formed from stratified loamy alluvium.

GEOGRAPHIC SETTING:
Elevation: 200 to 800 meters (655 to 2625 ft)
Parent material: organic material over silty loess over sandy and gravelly glaciolacustrine deposits
Landform: glacial lakes (relict), flats
Slopes: 0 to 10 percent
Mean annual precipitation: 300 to 1400 mm (12 to 55 in)
Mean annual air temperature: -5 to -1 degrees C. (23 to 30 degrees F)
Frost-free period: 60 to 103 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Basaltlake, Hundell, Manker, Squirrelcreek, Tiekel, and Uranatina soils.
Basaltlake soils are well drained, form in silty deposited over till, and occur on mountains.
Hundell soils are moderately well drained and occur on flats and bluffs in till plains and outwash plains.
Manker soils have permafrost, have cryoturbation, and occur on north facing slopes
Squirrelcreek soils are somewhat excessively drained, have alluvium as parent material, and occur on bluffs, floodplains, and river valleys in outwash plains.
Tiekel soils are very poorly drained, have a histic epipedon, cobbles and gravels in its O horizons, and occur on outwash plains and lake plains.
Uranatina soils are well drained, have mottles in Bw and C horizons, and occur on outwash plains and glacial lakes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: poorly drained
Saturated Hydraulic Conductivity:
Permeability:
Runoff: negligible

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: dwarf birch, spruce and moss

DISTRIBUTION AND EXTENT: MLRA 228 Interior Alaska mountains.
Extent: limited

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

SERIES ESTABLISHED: North Copper River Soil Survey, Alaska, 2024.

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

Particle-size control section: 41 to 116 cm (16 to 46 in)

Ochric epipedon: 0 to 23 cm (0 to 9 in) (Oi, Oa, and A horizons)

Aquic conditions: 23 to 150 cm (9 to 59 in) (A/Cg and Cg horizon)

Redoximorphic concentrations: 23 to 150 cm (9 to 59 in) (A/Cg and Cg horizon)

Depleted matrix: 23 to 150 cm (9 to 59 in) (A/Cg and Cg horizon)

ADDITIONAL DATA:

User pedon Id: 2022AK261007

National Cooperative Soil Survey
U.S.A.