LOCATION ABORIGINE               CA

Established Series
Rev. ACF-CAR-DJE-ET
01/2023

ABORIGINE SERIES

The Aborigine series consists of very deep, very poorly drained soils formed in marine or lacustrine sediments. Aborigine soils are on marine terraces and have slopes of 0 to 5 percent. The mean annual precipitation is about 1270 millimeters (50 inches) and the mean annual temperature is about 11 degrees C (53 degrees F).

TAXONOMIC CLASS: Fine, mixed, semiactive, isomesic Typic Albaquults

TYPICAL PEDON: Aborigine sandy loam - on a southwest facing slope of 5 percent under Mendocino cypress and Bolander pine at 600 feet elevation. Colors are for dry soil unless otherwise stated. When described on October 6, 1983 the soil was moist below 33 centimeters (13 inches).

Oi--0 to 8 centimeters (0 to 3 inches); fresh through decomposed litter of Mendocino cypress and Bolander pine.

E--8 to 23 centimeters(3 to 9 inches); variegated light gray (10YR 7/1) and white (N8/) sandy loam; light brownish gray (10YR 6/2) moist; massive; hard, friable, slightly sticky and nonplastic; slightly brittle when moist, slightly smeary; common very fine, fine and medium roots; common very fine and fine tubular and common very fine interstitial pores; extremely acid (pH 4.4); clear wavy boundary. (5 to 18 centimeters thick)

EB--23 to 41 centimeters(9 to 16 inches); very pale brown (10YR 7/3) loam, pale brown (10YR 6/3) moist; many fine and medium distinct brownish yellow (10YR 6/8) mottles, yellowish red (5YR 5/8) moist; weak fine and medium angular and subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine, fine and medium roots; common very fine tubular pores; 3 percent hard rounded very dusky red (10R 2.5/2) iron and manganese nodules (5-10mm); strongly acid (pH 5.5); abrupt wavy boundary. (0 to 23 centimeters thick)

2Btg--41 to 94 centimeters(16 to 37 inches); light gray (N7/) clay, light gray (10YR 7/1) moist; common medium and coarse prominent brownish yellow (10YR 6/8) and red (2.5YR 4/6) mottles, brownish yellow (10YR 6/8) and red (2.5YR 4/6) moist; strong coarse and very coarse prismatic structure parting to strong coarse a angular blocky; ped faces are stained gray (10YR 5/1, 6/1) with humic material; hard, firm, sticky and plastic; few very fine, fine and medium roots that are confined to areas between peds; few very fine tubular pores; many moderately thick and thick clay films on peds; extremely acid (pH 4.2); gradual dual wavy boundary. (38 to 64 centimeters thick)

3Btg--94 to 125 centimeters (37 to 49 inches); white (N8/) sandy clay, gray (10YR 6/1) moist; many coarse prominent red (10R 4/8) and common coarse prominent brownish yellow (10YR 6/8) mottles, red (2.5YR 4/6) and brownish yellow (10YR 6/8) moist; strong coarse prismatic structure parting to moderate coarse angular blocky structure; ped faces are stained gray (10YR 5/1, 6/1) with humic material; hard, firm, sticky and plastic; few very fine, fine and medium roots that are confined to areas between peds; few very fine tubular pores; many moderately thick and thick clay films on peds; extremely acid (pH 4.2); gradual dual wavy boundary. (25 to 50 centimeters thick)

4Btg1--125 to 147 centimeters(49 to 58 inches); white (N8/) sandy clay, gray (10YR 6/1) moist; common coarse prominent red (10YR 4/8) and brownish yellow (10YR 6/8) mottles, red (2.5YR 4/6) and brownish yellow (10YR 6/8) moist; moderate coarse angular blocky structure; extremely hard, firm, sticky and plastic; few very fine and fine roots that are confined to areas between peds; few very fine tubular pores; many moderately thick and thick clay films on peds; extremely acid (pH 4.2); clear wavy boundary. (5 to 15 inches thick)

4Btg2--147 to 163 centimeters(58 to 64 inches); gray (N6/) clay, gray (N5/) moist; common medium and coarse prominent brownish yellow (10YR 6/8) and red (10YR 4/8) mottles; brownish yellow (10YR 6/8) and red (2.5YR 4/6) moist; weak coarse angular blocky structure; hard, firm, sticky and plastic; few very fine and fine roots that are confined to areas between peds; few very fine tubular pores; many moderately thick and thick clay films on peds; extremely acid (pH 4.2). (Combined thickness of 4Btg horizons is 13 to 38 centimeters thick)

TYPE LOCATION: Mendocino County, California; about 107 meters (350 feet) north and 1402 meters (4600 feet) west of the southeast corner of sec. 3, T.17N., R.17W., MDBM, Comptche SW quadrangle.

RANGE IN CHARACTERISTICS:

Soil Moisture: The soil is saturated for extended periods during the months of December through April. These soils have an aquic moisture regime.

Soil Temperature: The mean annual soil temperature ranges from 10 to 13 degrees C (50 to 56 degrees F). The difference between the mean summer and mean winter temperature is 6 to 9 degrees F. These soils have an isomesic temperature regime.

Reaction is extremely through strongly acid (4.0 to 5.5).

Thickness of the solum and depth to bedrock is greater than 152 centimeters (60 inches).

O horizon:

Hue: 10YR.
Value: 2 through 6 dry and moist.
Chroma: 1 through 4 dry and moist.

Texture: slightly decomposed organic material.
Wood fragments: 0 to 35 percent.
Reaction: moderately to very strongly acid.

E horizon:

Hue: N, 5Y or 10YR.
Value: 5 through 8 dry, 3 through 7 moist.
Chroma: / though 3 dry, 1 through 3 moist.

Texture of fine earth: sandy loam or silt loam.
Rock fragments: 0 to 3 percent gravel.
Clay content: 5 to 27 percent.
Redoximorphic features: iron-manganese nodules in the matrix
Quantity: few or common


Some pedons have Eg horizons:

Eg horizon

Hue: 10YR.
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 1 through 2 dry or moist.

Texture of fine earth: silty clay loam.
Clay content: 35 to 40 percent.

Redoximorphic features: fine iron-manganese masses in the matrix, iron stains lining root channels and/or pores
Quantity: few to many
Hue: 10YR or 7.5YR
Value: 5 or 6
Chroma: 4 through 8

Btg horizon:

Hue: N, 5Y, 2.5Y, 10YR or 7.5YR.
Value: 6 through 8 dry, 5 through 8 moist.
Chroma: / through 3 dry or moist.

Texture of fine earth: clay loam, silty clay loam, sandy clay silty clay or clay
Rock fragments: 0 to 10 percent gravel; 0 to 45 percent paragravels.
Clay content: 35 to 55 percent.
Base saturation by barium chloride-TEA (pH 8.2) is 2 to 10 percent.

Redoximorphic features: fine iron-manganese masses in the matrix, iron stains lining root channels and/or pores
Quantity: few to many
Hue: 10YR, 7.5YR, 5YR, or 2.5YR
Value: 5 through 7
Chroma: 4 through 8


Some pedons have 2Bg horizons

2Bg horizon:

Hue: 10YR.
Value: 5 through 8 dry, 5 through 7 moist.
Chroma: 1 through 3 dry or moist.

Texture of fine earth: stratified layers of sandy clay loam, silty clay loam, sandy clay or silty clay.
Rock fragments: 0 to 5 percent gravel; 0 to 5 percent paragravels.
Clay content: 30 to 45 percent.

Redoximorphic features: fine or medium iron-manganese masses in the matrix, iron stains lining root channels and and/or pores
Quantity: common to many
Hue: 10YR or 7.5YR
Value: 5 to 6
Chroma: 4 through 8

Some pedons have 3Cg horizons
3Cg horizon:

Hue: N, 10BG or 5Y.
Value: 7 or 8 dry, 5 through 8 moist.
Chroma: / through 3 dry or moist.

Texture of fine earth: fine sandy loam or sandy clay loam
Rock fragments: 0 to 5 percent gravel; 0 to 5 percent paragravels.
Clay content: 15 to 25 percent.

Redoximorphic features: fine iron-manganese masses in the matrix, iron stains lining root channels and/or pores
Quantity: few to common
Hue: 10YR or 7.5YR
Value: 5 to 6
Chroma: 5 through 8

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Aborigine soils are on marine terraces and have slopes of 0 to 5 percent. The soils formed in marine or lacustrine sediments. Elevations are 76 to 244 meters (250 to 800 feet). The climate is humid with cool foggy summers and cool moist winters. A strong marine influence limits the diurnal and annual range of temperature. Mean annual precipitation ranges from 1015 to 1800 millimeters (40 to 70 inches). Mean January temperature is 48 degrees F., mean July temperature is 57 degrees F., and the mean annual temperature is 53 degrees F. The frost-free period is 260 to 330 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Blacklock and Burriscreek soils. Blacklock soils occur on the same landscape position and have an iron cemented hardpan (ortstein) at a depth of 25 to 50 centimeters (10 to 20 inches). Burriscreek soils are fine-silty with less than 35 percent clay in the particle size control section and well drained without redoximorphic features within 100 centimeters (40 inches). Burriscreek soils are found on linear to slightly convex, gently sloping shoulder and summit positions generally below the Savagecreek soils.

DRAINAGE AND PERMEABILITY: Very poorly drained. The soil is saturated with water for extended periods following episodes of heavy rain from December through April. The saturated zone starts between the surface and a depth of 25 centimeters (10 inches) and extends to greater than 152 centimeters (60 inches). The subsoil remains moist or wet throughout the year. Surface runoff under bare soil conditions is very slow or slow; very slow permeability.

USE AND VEGETATION: This soil is used as wildlife habitat and watershed. A few areas are used for homesites and commercial timber. Vegetation consists of Mendocino cypress, Bolander pine, shore pine, redwood, Douglas-fir, California huckleberry, Labrador tea and salal.

DISTRIBUTION AND EXTENT: Northern coastal California. The series is not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Mendocino County, California, Western Part, 1988.

REMARKS: The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET

Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - Albic horizon - 0 to 13 inches (E, EB) Clay content (Davis hydrometer) E = 6 percent, EB = 20 percent.

Argillic horizon - 13 to 61 inches 2Btg, 3Btg, 4Btg1, 4Btg2. Clay content (Davis hydrometer); 2Btg = 45 percent, 3Btg = 39 percent, 4Btg1 = 37 percent, 4Btg2 = 44 percent. Base saturation (Davis, Barium chloride pH 8.2). 2Btg = 5 percent, 3Btg = 7 percent, 4Btg1 = 6 percent. Discontinuities based on very fine sand fraction on a clay free basis.

Aquic moisture regime - Soil is saturated from December through April. Dominant moist chromas of 2 or less in argillic horizon, with associated high chroma mottles. Ped surfaces have moist chromas of 1 or less - 2Btg, 3Btg, 4Btg1, 4Btg2

Mineralogy assumed to be mixed but influenced by kaolinite.

Isomesic temperature regime - based on west Mendocino temp. site 5a that was in an area mapped as Aborigine. Site 5a had a difference between mean summer and mean winter temperatures of 9 degrees F.

Laboratory Analysis by U.C. Davis soil morphology lab sample No. 84-045-8 (1609).

Many areas mapped as Aborigine soils were mapped as the Blacklock series in the Wildlands Soils and Associated Vegetation of Mendocino County, by the State Cooperative Soil Vegetation Survey 1947-1950.

Scanned by SSQA 11/93. Last revised by state 10/90

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National Cooperative Soil Survey
U.S.A.