LOCATION PYRAMID AK

Established Series
Rev. CAP
04/2024

PYRAMID SERIES

Depth class: Shallow
Drainage class: Well drained
Parent material: moderately decomposed herbaceous organic material over sandy and loamy volcanic ash over medial gravelly silty volcanic ash over residuum weathered from graywacke
Landscape: Islands
Landform: mountains, hills, and ridges
Slopes: 0 to 80 percent
Mean annual precipitation: about 2250 mm (88.5 in)
Mean annual air temperature: -2 to 6 degrees C. (28 to 43 degrees F.)

TAXONOMIC CLASS: Medial-skeletal, ferrihydritic Lithic Humicryods

TYPICAL PEDON: Pyramid ashy sandy loam - in a spruce forest at elevation of 200 meters (660 feet). (All colors are for moist soil.)

Oe--0 to 3 centimeters (0 to 1 inches); very dark brown (7.5YR 2.5/2), brown (7.5YR 4/2), dry; moderately decomposed plant material; soft, very friable, nonsticky, nonplastic; many fine and common medium roots throughout; strongly acid (pH 5.1); clear smooth boundary. (0 to 10 cm, 0 to 4 in thick)

C1--3 to 10 centimeters (1 to 4 inches); pink (7.5YR 7/3), pink (7.5YR 8/3), dry; ashy sandy loam; weak fine granular structure; soft, very friable, nonsticky, nonplastic; many fine and common medium roots throughout; moderately acid (pH 5.6); gradual wavy boundary.

C2--10 to 21 centimeters (4 to 8 inches); light brown (7.5YR 6/4) ashy loamy sand; single grain; loose, nonsticky, nonplastic; common fine and medium roots throughout; moderately acid (pH 5.6); clear smooth boundary. (Combined thickness is 8 to 23 cm, 3 to 9 in)

2A--21 to 25 centimeters (8 to 10 inches); dark grayish brown (10YR 4/2) gravelly medial silt loam; weak fine granular structure; soft, very friable, nonsticky, nonplastic; common fine and medium roots throughout; 15 percent gravel and 5 percent cobble; very strongly acid (pH 5.0); gradual smooth boundary. (2 to 8 cm, 1 to 3 in thick)

2Bhs1--25 to 35 centimeters (10 to 14 inches); dark brown (7.5YR 3/3) very gravelly highly organic medial silt loam; weak fine angular blocky structure; soft, very friable, nonsticky, nonplastic; common fine roots throughout; 35 percent gravel and 5 percent cobble; strongly acid (pH 5.1); gradual smooth boundary.

2Bhs2--35 to 41 centimeters (14 to 16 inches); dark brown (7.5YR 3/3) very gravelly medial highly organic silt loam; weak fine angular blocky structure; soft, very friable, nonsticky, nonplastic; common fine roots throughout; 40 percent gravel and 5 percent cobble; strongly acid (pH 5.2); clear smooth boundary. (Combined thickness is 10 to 28 cm, 4 to 11 in)

2Bs--41 to 44 centimeters (16 to 18 inches); brown (7.5YR 4/4) very gravelly medial silt loam; massive; soft, very friable, nonsticky, nonplastic; common (1.0) fine roots throughout; 5 percent by volume nonflat subangular very strongly coherent cemented 76-160-250 millimeter unspecified fragments and 40 percent by volume nonflat subangular very strongly coherent cemented 2-40-75 millimeter unspecified fragments; strongly acid (pH 5.2); abrupt wavy boundary. (0 to 13 cm, 0 to 5 in)

3R--44 to 69 centimeters (18 to 28 inches); strongly to indurated bedrock derived from graywache.

TYPE LOCATION: Kodiak Archipelago Soil Survey Area, Alaska; Latitude 57 degrees 36 minutes 14.00 seconds and Longitude 152 degrees 23 minutes 3.00 seconds west, UTM north 6384778.33 and UTM east 536802.21, zone 5, Datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: Udic
Mean annual soil temperature: 1.6 to 3.3 degrees C. (34.8 to 37.9 degrees F.)
Thickness of organic material: 0 to 10 cm (0 to 4 in)
Thickness of 1912 Ash: 8 to 23 cm (3 to 9 in)
Depth to andic properties: 8 to 33 cm (3 to 13 in)
Depth to spodic horizon: 10 to 41 cm (4 to 16 in)
Depth to lithic contact: 20 to 50 cm (8 to 20 in)

Oa, Oe, Oi horizon:
Hue: 7.5YR to 10 YR
Value: 2 to 5
Chroma: 1 to 4
Texture: slightly, moderately, or highly decomposed plant material
Organic matter: 60 to 90 percent
Reaction class: extremely acid to moderately acid (pH 3.5 to 6.0)

C horizon:
Hue: 7.5 YR to 10 YR
Value: 4 to 8
Chroma: 1 to 6
Texture: (ashy and glassy) sand, loamy sand, loamy fine sand, very fine sandy loam, sandy loam, or silt loam
Sand: 30 to 90 percent
Clay: 2 to 8 percent
Silt: 10 to 55 percent
Reaction Class: extremely acid to moderately acid (pH 3.5 to 6.0)

2A horizon:
Hue: 5YR, 7.5YR, or 10YR
Value: 2 to 5
Chroma: 1 to 3
Texture: (medial) silt loam, silt, loam, or very fine sandy loam
Silt: 40 to 90 percent
Clay: 2 to 10 percent
Rock Fragments: 0 to 14 percent
Reaction Class: extremely acid to moderately acid (pH 3.5 to 6.0)

2Bhs or 2Bs horizon:
Hue: 5YR, 7.5YR, or 10YR
Value: 2 or 3
Chroma: 1 to 4
Texture: (medial) silt loam, silt, loam, or very fine sandy loam, or their gravelly analogues
Silt: 40 to 90 percent
Clay: 2 to 12 percent
Rock Fragments: 0 to 25 percent
Reaction Class: extremely acid to moderately acid (pH 3.5 to 6.0)

3R horizon: Strongly to indurated bedrock derived from graywacke.

Some pedons have lithic contacts at depths greater than 50 cm (20 in) and/or skeletal till substratum above the lithic contact.

COMPETING SERIES: This is the Hannegan (WA) series.
Hannegan soils have loess sediments in the upper part, have phyllite bedrock, have annual precipitation greater than 2300 mm (90 in), and occur on similar landform positions.

GEOGRAPHIC SETTING:
Elevation: 100 to 1300 meters (325 to 4300 feet)
Parent material: decomposed organic material over sandy and loamy volcanic ash over medial silty volcanic ash over residuum weathered from graywacke
Landform: mountains, hills, and ridges on summits, shoulders, and back slopes or flanks
Slope: 0 to 80 percent
Mean annual precipitation: 1500 to 3000 mm (84 to 118 in)
Mean annual temperature: -2 to 6 degrees C. (28 to 43 degrees F.)
Frost free period: 20 to 50 days

GEOGRAPHICALLY ASSOCIATED SOILS: These include Kaguyak, Kazakof, Kodiak, Marka, Port Lions, Pyramid, and Shuyak.
Kaguyak soils lack spodic horizons, have skeletal control sections, and occur are similar landform positions.
Kazakof soils have are moderately deep to lithic contact, and occur on similar landform positions.
Kodiak soils lack lithic contacts, have loamy skeletal till substratum, and occur on flanks, backslopes, and foot slopes.
Marka soils have lithic contacts greater than 50 cm (20 in), have loamy skeletal till substratum, and occur on similar landform positions.
Port Lions soils have lithic contacts greater than 50 cm (20 in) and occur on similar landform positions.
Pyramid soils have skeletal control sections and occur on similar landform positions.
Shuyak soils lack spodic horizons and occur are similar landform positions.

DRAINAGE AND PERMEABILITY:
Drainage class: well drained
Saturated Hydraulic Conductivity: very high in the C horizon and moderately high to high in the 2A and Bhs horizons.
Permeability: rapid to very rapid in the C horizon and moderately rapid to rapid in the 2A and Bhs horizons.
Runoff: high to very high.

USE AND VEGETATION:
On slopes of less than 45 percent the soils are used as rangeland. The native vegetation is tall grass, dominantly bluejoint reedgrass, and associated plants including fireweed, salmonberry, and alder. A few patches of white spruce, Sitka spruce, and paper birch occur in places.

DISTRIBUTION AND EXTENT: MLRA 220 Alexander Archipelago-Gulf of Alaska Coast.
Extent: moderate.

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

SERIES ESTABLISHED: Kodiak Archipelago Soil Survey, Alaska, 2024.
Extent: moderate.

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

Organic material: 0 to 3 cm (0 to 1 in) (moderately decomposed hemic plant material) (Oe horizon)

1912 volcanic glass (ashy) material: 3 to 21 cm (1 to 8 in) (C horizon)

Andic soil properties: 21 to 44 cm (8 to 17 in) (2A, 2Bhs, 2Bs horizons)

Spodic horizon: 25 to 44 cm (10 to 17 in) (2Bhs, 2Bs horizons)

Lithic contact: 44 to 69 cm (17 to 27) (3R horizon)

Source of the volcanic ash is the 1912 eruption of Mt. Novarupta and Mt. Katmai on the Alaska Peninsula.

ADDITIONAL DATA:

User pedon Id: 08AO 01005

National Cooperative Soil Survey
U.S.A.