LOCATION KODIAK                  AK

Established Series
Rev. SR
05/2022

KODIAK SERIES

The Kodiak series consists of deep, well drained soils formed in several sequences of volcanic ash overlying weathered bedrock or glacial till. Slopes range from 3 to 80 percent. Mean annual temperature is about 40 degrees F., and the average annual precipitation is about 60 inches.

TAXONOMIC CLASS: Medial over loamy-skeletal, mixed, superactive Typic Vitricryands

TYPICAL PEDON: Kodiak silt loam -- under native grass (All colors are for moist soil)

Oi--4 to 1 inch; litter of straw and alder leaves. (2 to 4 inches thick)

Oe--1 inch to 0; dark brown (10YR 3/3) mat of partially decomposedorganic aterials; extremely acid; abrupt smooth boundary. (1 to 2 inches thick)

C1--0 to 2 inches; light gray (10YR 7/1) silt loam volcanic ash; weak fine platy structure; firm in place, friable disturbed; few fine roots; extremely to very strongly acid; abrupt smooth boundary. (1 to 2 inches thick)

C2--2 to 6 inches; light yellowish brown (10YR 6/4) silt loam volcanic ash; massive; firm in place, friable when disturbed; few roots; very strongly acid; abrupt smooth boundary. (2 to 5 inches thick)

2C3--6 to 8 inches; light yellowish brown (10YR 6/4) loamy fine sand volcanic ash; single grained; loose; few roots; very strongly to strongly acid; clear wavy boundary. (1 to 3 inches thick)

2C4--8 to 11 inches; grayish brown (10YR 5/2) fine sand volcanic ash; single grained; loose; few roots; strongly acid; abrupt smooth boundary. (3 to 4 inches thick)

3A1b--11 to 15 inches; dark reddish brown (5YR 2/2) silt loam; weak fine subangular blocky structure; very friable; many roots; extremely acid; abrupt wavy boundary. (4 to 7 inches thick)

3A2b--15 to 23 inches; dark reddish brown (5YR 3/3) silt loam; moderate medium subangular blocky structure; friable; sticky; streaks of brown (7.5YR 4/2); few roots; very strongly acid; gradual boundary. (6 to 8 inches thick)

3Bb--23 to 27 inches; brown (7.5YR 4/2) gravelly silt loam; many angular rock fragments; abrupt wavy boundary. (2 to 15 inches thick)

4C--27 to 40 inches +; olive (5Y 4/3) very gravelly sandy loam; mottled with reddish brown; very strongly acid.

TYPE LOCATION: Northeastern Kodiak Island Area, Alaska. 1.3 miles north of Naval Ski Chalet along Anton Larsen Bay Road.

RANGE IN CHARACTERISTICS: Total thickness of recent volcanic ash varies from only a few inches to 15 inches, but the normal range in thickness is 9 to 12 inches. In isolated places where much of the ash was washed off shortly after deposition, the uppermost layer may be loamy fine sand. A few angular cobbles may occur in the B horizon of the buried soil. The substratum is commonly weathered or transported slate and graywacke, but in places, it consists of other rocks.

COMPETING SERIES: This is the Sharatin series in the same subgroup. Sharatin soils are sandy-skeletal in the lower part of the control section.

GEOGRAPHIC SETTING: Kodiak soils are on undulating to steep slopes in glaciated uplands; most commonly they are formed on irregular topography with slopes of 12 to 45 percent. Parent materials are volcanic ash over glacial till or weathered rock. The climate is cool maritime. Average annual precipitation ranges from 50 to 70 inches, and the average annual temperature is about 40 degrees F. Temperatures below freezing are recorded on fewer than 40 days annually, and temperatures above 70 degrees F. are rare.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Sharatinseries a d the Saltery and Ugak series. Saltery soils are formed in sedge peats. Ugak soils are poorly drained soils formed in the same materials as Kodiak soils.

DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability. Runoff is slow to rapid.

USE AND VEGETATION: Used as range land. Areas on more gentle and smoother slopes are used for hay or silage and, to a limited extent, for garden vegetables. Some timber is taken from forested areas. The native vegetation is mostly tall grass, dominantly bluejoint reedgrass, and associated plants such as fireweed and salmonberry. Large patches of alder are common. In some areas, the grass and alder have been invaded and comnpletely replaced by Sitka spruce forest.

DISTRIBUTION AND EXTENT: Northern Kodiak Island, Alaska, and adjacent islands. The series is extensive.

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

SERIES ESTABLISHED: Northeastern Kodiak Island Area, Alaska, 1959.

REMARKS: The concept of the Kodiak series is poorly defined, especially in regard to substratum materials. More data is needed to define the central concept or the series should be inactivated (jpm, 4/87).

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

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National Cooperative Soil Survey
U.S.A.