LOCATION GEARHART                OR

Established Series
Rev. GEO/PRS/TDT/MHF
06/2011

GEARHART SERIES

The Gearhart series consists of very deep, somewhat excessively drained soils that formed in eolian sand deposits. They are on stabilized sand dunes and have slopes of 0 to 30 percent. The mean annual precipitation is about 85 inches and the mean annual temperature is about 52 degrees F.

TAXONOMIC CLASS: Mixed, isomesic Psammentic Humudepts

TYPICAL PEDON: Gearhart fine sandy loam - native vegetation. (Colors are for moist soil unless otherwis noted.)

Oi--0 to 1 inch; slightly decomposed litter of leaves, needles, moss and twigs.

A--1 to 12 inches; black (10YR 2/1) fine sandy loam, very dark gray (10YR 3/1) dry; single grain; loose, nonsticky and nonplastic; many fine and very fine roots; many very fine irregular pores; very strongly acid (pH 4.6); abrupt smooth boundary. (10 to 20 inches thick)

Bw--12 to 17 inches; dark brown (7.5YR 3/3) sand, brown (7.5YR 5/4) dry; single grain; loose, nonsticky and nonplastic; common very fine roots; many very fine irregular pores; common reddish brown (2.5YR 4/4) streaks; very strongly acid (pH 5.0); gradual irregular boundary. (4 to 11 inches thick)

C1--17 to 46 inches; dark gray (10YR 4/1) sand, gray (10YR 6/1) dry; single grain; loose, nonsticky and nonplastic; many very fine irregular pores; few reddish brown (2.5YR 4/4) streaks; very strongly acid (pH 4.8); diffuse wavy boundary. (25 to 35 inches thick)

C2--46 to 61 inches; gray (10YR 5/1) sand, gray (10YR 6/1) dry; single grain; loose, nonsticky and nonplastic; many very fine irregular pores; very strongly acid (pH 4.8).

TYPE LOCATION: Clatsop County, Oregon; on top of a stabilized dune 20 feet south of Camp Kiwanilong road about 500 feet south west of its junction with the Fort Stevens road; NW1/4SE1/4 section 20, T. 8 N., R. 10 W.

RANGE IN CHARACTERISTICS: The soil is usually moist and is dry for less than 45 consecutive days between the depths of 12 to 36 inches. The mean annual soil temperature is 51 to 54 degrees F. The mean winter soil temperature is 48 to 52 degrees F. The mean summer soil temperature is 53 to 59 degrees F. The difference between the mean winter and mean summer soil temperature is 5 to 9 degrees F. The umbric epipedon is 10 to 20 inches thick.

The A horizon has value of 2 or 3 moist, 3 or 4 dry and chroma of 1 or 2 moist and dry. It is fine sandy loam or loamy fine sand. It is extremely acid or very strongly acid.

The Bw horizon has hue of 5YR, 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. It is sand or fine sand with 5 to 10 percent clay. Some pedons lack the reddish brown streaks. It is very strongly acid or strongly acid.

The C horizon has hue of 10YR, 2.5Y, or 5Y, value of 4 or 5 moist, 6 or 7 dry and chroma of 1 through 4 moist and dry. It is sand or fine sand with 3 to 5 percent clay. It is very strongly acid or strongly acid.

COMPETING SERIES: There are no other series in this family. The Frankport and Waldport series lack an umbric epipedon.

GEOGRAPHIC SETTING: Gearhart soils are on long narrow stabilized sand dunes roughly parallel to the Pacific Ocean at elevations of 15 to 200 feet. Slopes are 0 to 30 percent. The soils formed in eolian sand deposits. The climate is cool and wet during the winter and has many days of low cloud and fog cover during the summer. A strong marine influence limits the diurnal and annual range of temperature. Mean January temperature is about 43 degrees F., and mean July temperature is about 60 degrees F. The mean annual temperature is 49 to 53 degrees F. The mean annual precipitation is 60 to 100 inches. The frost-free period is 210 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ferrelo, Frankport, Netarts, Warrenton, and Waldport soils. Ferrelo soils are coarse-loamy. Frankport and Waldport soils are coarse-textured. Netarts soils have a spodic horizon. Warrenton soils are in swales between dunes and are poorly drained.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very rapid permeability.

USE AND VEGETATION: These soils are used for pasture, watershed, limited timber production, building sites, and recreation. Native vegetation includes Sitka spruce, shore pine, red alder, Scotch-broom, salal, western swordfern, trailing blackberry, European beachgrass, and strawberries. Many areas have been planted to shore pine.

DISTRIBUTION AND EXTENT: Coastal areas of Oregon; MLRA 4A. The series is inextensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Clatsop County, Oregon, 1938.

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

Umbric epipdeon - from 1 to a depth of 12 inches (A horizon).

All diagnostic horizons and features are measured from the top of the first mineral horizon.

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National Cooperative Soil Survey
U.S.A.