LOCATION TIGARAHA AK
Established Series
Rev. MHC/DLM
02/2022
TIGARAHA SERIES
Depth class: moderately deep
Drainage class: well drained
Landforms: mountains
Parent material: silty eolian deposits over gravelly residuum weathered from schist
Elevation: 568 to 2228
Slope: 0 to 65 percent
Annual precipitation: 22 to 27 inches
Annual temperature: 23 to 25 degrees F
Frost-free period: 60 to 90 days
TAXONOMIC CLASS:
TYPICAL PEDON: Tigahaha silt loam - on a slope of 2 percent under ericaceous shrub/lichen dwarf scrub. (All colors are for moist soil)
Oe--0 to 0.5 inches; very dark brown (7.5YR 2.5/2) moderately decomposed plant material; many very fine and fine and few medium roots; 5 percent channers; 45 percent mica flakes in the fine earth fraction; very strongly acid (pH 4.6); clear wavy boundary.
A--0.5 to 2 inches; very dark grayish brown (10YR 3/2) silt loam; very friable, nonsticky and nonplastic; many very fine and fine and few medium roots; 10 percent channers; 45 percent mica flakes in the fine earth fraction; extremely acid (pH 4.4); clear wavy boundary.
2Bw--2 to 15 inches; olive brown (2.5Y 4/3) very channery loam; friable, nonsticky and nonplastic; common very fine and fine roots; 45 percent channers, 10 percent flagstones; 55 percent mica flakes in the fine earth fraction; very strongly acid (pH 4.9); gradual wavy boundary.
2C--15 to 23 inches; olive gray (5Y 4/2) very channery loam; friable, nonsticky and nonplastic; 45 percent channers, 10 percent flagstones; 55 percent mica flakes in the fine earth fraction; strongly acid (pH 5.1); clear wavy boundary.
2Cr--23 to 60 inches; fractured bedrock.
TYPE LOCATION: Steward River Training Site Area, Alaska; UTM coordinates: Zone 3, Easting 476482, Northing 7182176
RANGE IN CHARACTERISTICS:
Soil moisture class: udic
Average annual soil temperature: about29 degrees F.
Mean summer soil temperature: about 35 degrees F.
Depth to bedrock (paralithic): 20 to 40 inches
Depth to strongly contrasting textural stratification: 0 to 1 inch
Oe horizon:
Hue: 5YR, 7.5YR or 10YR
Value: 2 or 2.5
Chroma: 1 to 3
Organic matter content: 85 to 95 percent
Reaction: extremely acid to moderately acid
A horizon:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 to 3
Clay content: 0 to 10 percent
Silt content: 50 to 80 percent
Sand content: 15 to 50 percent
Organic matter content: 2 to 8 percent
Rock fragments: 0 to 10 percent strongly cemented channers, 0 to 2 percent strongly cemented flagstones
Reaction: extremely acid to moderately acid
2Bw horizon:
Hue: 7.5YR to 2.5Y
Chroma: 3 or 4
Texture: very channery loam, very channery silt loam, extremely channery silt loam
Clay content: 0 to 10 percent
Silt content: 40 to 65 percent
Sand content: 25 to 50 percent
Organic matter content: 1 to 5 percent
Rock fragments: 25 to 50 percent strongly cemented channers, 0 to 20 percent strongly cemented flagstones
Reaction: very strongly acid to slightly acid
2C horizon:
Hue: 10YR, 2.5Y or 5Y
Value: 2.5 to 4
Chroma: 1 to 3
Texture: very channery loam, very channery silt loam, extremely channery silt loam
Clay content: 0 to 10 percent
Silt content: 40 to 65 percent
Sand content: 25 to 50 percent
Rock fragments: 25 to 50 percent strongly cemented channers, 0 to 20 percent strongly cemented flagstones
Reaction: strongly acid to slightly alkaline
COMPETING SERIES: There are no competing series in this classification.
GEOGRAPHIC SETTING:
Landforms: mountains
Parent material: silty eolian deposits over gravelly residuum weathered from schist
Elevation: 568 to 2228
Slope: 0 to 65 percent
Annual precipitation: 22 to 27 inches
Annual temperature: 23 to 25 degrees F
Frost-free period: 60 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
DRAINAGE AND PERMEABILITY: Well drained, low runoff. Saturated hydraulic conductivity is high.
USE AND VEGETATION: Used for military use and wildlife habitat. Native vegetation is ericaceous shrub/lichen dwarf scrub.
DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hills-Southern Seward 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:
Paralithic contact: 23 inches. (Cr horizon)
Depth to permafrost: * to * inches. (* horizon)
Cambic horizon: 2 to 15 inches. (2Bw horizon)
Lithologic discontinuity: At the upper boundary of 2Bw horizon
Loamy-skeletal particle size control section: 10 to 23 inches
Temperature regime: cryic
ADDITIONAL DATA:
The mineralogy class was changed from paramicaceous to micaceous in 07/2010 by the National Soil Survey Center on request of the responsible MLRA regional office. The change was necessary based on the eleventh edition of the Keys to Soil Taxonomy, 2010.
National Cooperative Soil Survey
U.S.A.