LOCATION UNIONPEAK          OR
Established Series
Rev. ACM/TDT
03/2002

UNIONPEAK SERIES


The Unionpeak series consists of moderately deep to a very weakly to weakly cemented duripan, somewhat excessively drained soils that formed in ash deposits derived from volcanic ash, pumice, cinders, andesite, and dacite. Unionpeak soils are on ash flows and have slopes of 0 to 35 percent. The mean annual precipitation is about 55 inches and the mean annual temperature is about 41 degrees F.

TAXONOMIC CLASS: Ashy, amorphic Typic Duricryands

TYPICAL PEDON: Unionpeak ashy sandy loam, on a 2 percent slope, forest. (Colors are for moist soils unless otherwise noted. Described by T. Clark and G. Weinheimer, 9/21/99.)

Oi--0 to 1 inch; slightly decomposed needle litter; abrupt wavy boundary. (1 to 3 inches thick)

A1--1 to 4 inches; very dark grayish brown (10YR 3/2) ashy sandy loam, brown (10YR 5/3) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine and medium roots; many interstitial pores; 2 percent andesite gravel, 3 percent cinder gravel, and 5 percent pumice paragravel; moderately acid (pH 6.0); clear wavy boundary. (2 to 8 inches thick)

A2--4 to 8 inches; brown (10YR 4/3) ashy loamy sand, dark yellowish brown (10YR 4/4) dry; weak very fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; common very fine interstitial and common fine dendritic tubular pores; 2 percent andesite gravel, 3 percent cinder gravel, and 5 percent pumice paragravel; moderately acid (pH 6.0); clear wavy boundary. (0 to 9 inches thick)

Bw--8 to 30 inches; brown (10YR 4/3) gravelly ashy loamy sand, light brownish gray (10YR 6/2) dry; weak very fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and few fine, medium, and coarse roots; common very fine interstitial pores; 4 percent andesite gravel, 10 percent cinder gravel, and 7 percent pumice paragravel; neutral (pH 6.6); gradual wavy boundary. (6 to 23 inches thick)

Bqm--30 to 45 inches; dark grayish brown (10YR 4/2) weakly cemented ashy loamy sand, light brownish gray (10YR 6/2) dry; massive parting to medium and coarse platy rock-like structure; hard, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; common, distinct relict redox concentrations on surfaces of plates; 5 percent andesite gravel and 5 percent cinder gravel; slightly acid (pH 6.4); clear wavy boundary. (12 to 35 inches)

C--45 to 65 inches; dark reddish brown (5YR 3/3) gravelly ashy loamy sand, reddish brown (5YR 5/3) dry; single grain; loose, nonsticky and nonplastic; many fine interstitial pores; 25 percent cinder gravel and 1 percent cinder cobbles; slightly acid (pH 6.4).

TYPE LOCATION: Klamath County, Oregon, Crater Lake National Park; about 1.5 miles SE of Rim Drive junction on the old east entrance road and about 700 feet north of the road; UTM Zone 10, 577121 easting, 4750550 northing, NAD 83 (GPS). Latitude - 42 degrees, 54 minutes, 14 seconds North; Longitude - 122 degrees, 03 minutes, 19 seconds West.

RANGE IN CHARACTERISTICS: The depth to the very weak to weakly cemented duripan is 20 to 40 inches. The average annual soil temperature ranges from 39 to 43 degrees F. The soils are usually moist but are dry in all parts of the moisture control section for 30 to 45 consecutive days following the summer solstice. Andic soil properties are present throughout a thickness of 20 to 40 inches and has 60 to 90 percent volcanic glass, 1.0 to 2.5 acid oxalate extractable aluminum plus one-half iron, 50 to 85 percent phosphate retention, 3 to 12 percent air-dry 15-bar water content and 4 to 13 percent undried 15 bar water. The weighted average 8xSi+2xFe is 5 to 8. The particle size control section averages less than 35 percent rock and pararock fragments.

The A horizon has value of 2 or 3 moist, 3 through 5 dry, and chroma of 2 or 3 moist and dry. It contains 0 to 15 percent pumice paragravel, 0 to 10 percent cinder gravel, and 0 to 5 percent andesite gravel.

The Bw horizon has value of 3 or 4 moist, 4 through 6 dry, and chroma of 2 or 3 moist and dry. It is ashy loamy sand or ashy sandy loam and contains 0 to 10 percent pumice paragravel, 0 to 10 percent cinder gravel, and 0 to 5 percent andesite gravel.

The Bqm horizon is very weakly to weakly cemented.

The C horizon has hue of 5YR, 7.5YR, or 10YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is ashy loamy sand or ashy sand. The upper part has a dry consistence of hard and the lower part has a dry consistence of slightly hard or soft. It contains 0 to 30 percent pumice paragravel, 0 to 25 percent cinder gravel, 0 to 15 percent andesite gravel, and 0 to 5 percent cinder cobbles.

COMPETING SERIES: This is the tentative Onionpie series. Onionpie soils have a xeric moisture regime.

GEOGRAPHIC SETTING: Unionpeak soils are on ash flows at elevations of 4,500 to 7,000 feet. Slopes range from 0 to 35 percent. The soils formed in ash deposits derived mainly from volcanic ash, pumice, andesitic cinders, and andesite from Mt. Mazama. The climate is characterized by cold wet winters and cool moist summers. The mean annual precipitation is 40 to 70 inches, falling mainly as snow. The mean annual air temperature is 38 to 42 degrees F and the frost-free period is 0 to 50 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Castlecrest, Llaorock, Redcone, Timbercrater, and Umak series. Llaorock is medial-skeletal and on adjacent ridges. Redcone is ashy-skeletal. Timbercrater and Umak are ashy-pumiceous.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; runoff is moderate. Permeability is rapid throughout the solum and moderately rapid in the Bqm horizon.

USE AND VEGETATION: These soils are used for woodland, wildlife habitat, watershed, and recreation purposes. Vegetation is mountain hemlock, Shasta red fir, and lodgepole pine with a sparse understory of shrubs and herbs.

DISTRIBUTION AND EXTENT: The High Cascade Mountains of south central Oregon; MLRA 3. This series is of limited extent.

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

SERIES ESTABLISHED: Crater Lake National Park, Oregon, 2001.

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

Andic soil properties - from 1 to 30 inches

Ochric epipedon

Vitri (greatgroup) - the solum averages 60 to 90 percent volcanic glass and has an air-dry 15-bar water content of 3 to 12 percent

All depths to diagnostic horizons and features found in the range of characteristics are measured from the top of the first mineral horizon.

Runoff is moderate due to the hydrophobic nature of the surface horizon. If this property is not present, depending on slope, runoff may be low.

ADDITIONAL DATA: Reference samples S00OR-035-003; the reference sample pedon is a taxadjunct in that it is glassy with a value of 4.3 for 8xSi+2xFe.


National Cooperative Soil Survey
U.S.A.