LOCATION PIONEER PEAK AK

Established Series
Rev. DM
02/2022

PIONEER PEAK SERIES

The Pioneer Peak series consists of very deep, somewhat poorly drained soils formed in ash influenced eolian deposits over gravelly glacial drift. Pioneer Peak soils are on depressions in drainageways, till plains, and hills. Slopes range from 0 to 20 percent. The mean annual precipitation is about 16 inches, and the mean annual temperature is about 36 degrees F.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Aquic Haplocryods

TYPICAL PEDON: Pioneer Peak silt loam - on 2 percent slope under forest. (All colors are for moist soil)

Oa--0 to 3 inches; highly decomposed plant material; very strongly acid (pH 5.0); abrupt smooth boundary. (2 to 5 inches thick)

E/B--3 to 5 inches; 80 percent dark gray (2.5Y 4/1) and 20 percent brown (7.5YR 4/4) silt loam; weak medium platy structure parting to weak fine granular; very friable, slightly sticky and slightly plastic; common very fine and fine roots; smeary; very strongly acid (pH 5.0); clear wavy boundary. (1 to 3 inches thick)

Bs--5 to 10 inches; dark brown (7.5YR 3/4) silt loam; weak fine subangular blocky structure; very friable, slightly sticky and slightly plastic; common very fine and fine roots; smeary; strongly acid (pH 5.3); clear wavy boundary. (3 to 7 inches thick)

Eb/Bsb--10 to 14 inches; 60 percent dark gray (2.5Y 4/1) and 40 percent brown (7.5YR 4/4) silt loam; weak medium platy structure parting to weak fine granular; very friable, slightly sticky and slightly plastic; few very fine and fine roots; smeary; strongly acid (pH 5.3); clear wavy boundary (0 to 6 inches thick)

Bsb--14 to 15 inches; dark brown (7.5YR 3/4) silt loam; weak fine subangular blocky structure; very friable, slightly sticky and slightly plastic; few very fine and fine roots; smeary; moderately acid (pH 5.7); clear wavy boundary. (0 to 7 inches thick)

Eb--15 to 22 inches; dark gray (2.5Y 4/1) silt loam; weak fine subangular blocky structure; very friable, slightly sticky and slightly plastic; few very fine and fine roots; smeary; moderately acid (pH 5.7); clear wavy boundary (0 to 9 inches thick)

Bsb1--22 to 25 inches; dark brown (7.5YR 3/4) silt loam; weak fine subangular blocky structure; very friable, slightly sticky and slightly plastic; few very fine and fine roots; smeary; many prominent dark gray (2.5Y) redoximorphic depletions; moderately acid (pH 5.7); clear wavy boundary. (0 to 7 inches thick)

2BC--25 to 37 inches; dark grayish brown (2.5Y 4/2) gravelly loam; weak fine subangular blocky structure; friable, slightly sticky and slightly plastic; few very fine and fine roots; 20 percent gravel; many prominent brown (7.5YR 4/4) redoximorphic concentrations; moderately acid (pH 5.8); clear wavy boundary. (5 to 17 inches thick)

2C--37 to 60 inches; dark grayish brown (2.5Y 4/2) very gravelly sandy loam; massive; friable, nonsticky and nonplastic; 15 percent coarse gravel, 30 percent fine gravel, and 5 percent cobbles; many prominent brown (7.5YR 4/4) redoximorphic concentrations; slightly acid (pH 6.4).

TYPE LOCATION: Anchorage Area, Alaska; about 4.5 miles northeast of Eagle River; in the NE 1/4 of the SW 1/4, section 20, T. 15 N., R. 2 W.; Anchorage B8NE 1:25,000 quad, Seward Meridian; UTM north 6807315 and UTM east 0357729, zone 6.

RANGE IN CHARACTERISTICS: Depth to gravelly glacial drift ranges from 20 to 40 inches. Coarse fragments in the eolian mantle ranges from 0 to 10 percent gravel. Coarse fragments in the glacial drift range from 15 to 60 percent gravel and 0 to 10 percent cobbles. Reaction is very strongly acid through moderately acid in the solum. Depth to highest water table is about 1 1/2 to 2 1/2 feet from mid April to mid June. Depth to water table is about 1 1.2 to 5 feet throughout the year.

The E horizon has hue of 7.5YR to 2.5Y, value of 3 to 5, and chroma of 1 or 2. The texture is silt loam or loam.

The Bs horizon has value of 3 or 4, and chroma of 3 or 4. The texture is silt loam, loam, or fine sandy loam.

The Eb/Bsb horizon has hue of 7.5YR to 2.5Y, value of 3 to 5, and chroma of 1 or 2 (Eb) and value of 3 or 4, and chroma of 3 or 4 (Bsb). The texture is silt loam, loam, or fine sandy loam.

The Bsb horizons (where present) has value of 3 or 4, and chroma of 3 or 4. The texture is silt loam, loam, or fine sandy loam.

The Eb horizon (where present) has hue of 7.5YR to 2.5Y, value of 3 to 5, and chroma of 1 or 2. The texture is silt loam, loam, or fine sandy loam.

The 2BC horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2 or 3. The texture is fine sandy loam, loam, or silt loam modified by 15 to 30 percent gravel, and 0 to 10 percent cobbles.

The 2C horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2 or 3. The texture is loamy sand or sandy loam modified by 35 to 60 percent gravel, and 3 to 10 percent cobbles.

COMPETING SERIES: This is the Matsu (T) series. Matsu series do not have very gravelly substratums.

GEOGRAPHIC SETTING: The Pioneer Peak soils occur on depressions in drainageways, till plains, and hills. Slopes range from 0 to 20 percent. The soils formed in ash influenced eolian deposits over gravelly glacial drift. Mean annual temperature ranges from 29 to 43 degrees F. Mean annual precipitation ranges from 14 to 20 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These include Kashwitna, Jacobsen, and Doroshin soils. Kashwitna soils are well drained. Doroshin and Jacobsen soils are very poorly drained.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained, low or medium runoff. Permeability is moderate in the loess mantle and moderately rapid to rapid in the substratum.

USE AND VEGETATION: Wildlife habitat, recreation, and homesite and urban development where the soils have been drained.

DISTRIBUTION AND EXTENT: Cook Inlet-Susitna Lowlands. The series is of small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES ESTABLISHED: Anchorage Area, Alaska, 2001

REMARKS: Diagnostic features and horizons recognized in this profile include: albic and spodic horizons from 3 to 25 inches; redoximorphic features from 22 to 60 inches; cryic temperature regime.

ADDITIONAL DATA:

National Cooperative Soil Survey
U.S.A.