Classification of the Soils
Unionpeak Series
Depth class: Moderately deep to a duripan
Drainage class: Somewhat excessively drained
Permeability: Rapid throughout the solum and moderately rapid in the Bqm horizon
Position on landscape: Ashflows
Parent material: Pumice, ash, and andesite and dacite fragments
Slope range: 0 to 35 percent
Elevation: 4,500 to 7,000 feet
Average annual precipitation: 40 to 70 inches
Average annual air temperature: 38 to 42 degrees F
Frost-free period: 0 to 50 days
Taxonomic class: Ashy, amorphic Typic Duricryands
Typical Pedon
Oi—0 to 1 inch; slightly decomposed needle litter; abrupt wavy boundary.
A1—1 inch 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 roots and few fine and medium roots; many very fine interstitial pores; 2 percent andesite gravel, 3 percent cinder gravel, and 5 percent pumice paragravel; moderately acid (pH 6.0); clear wavy boundary.
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 roots and few medium roots; common very fine interstitial pores 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.
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 roots and few fine, medium, and coarse roots; common very fine interstitial pores; 15 percent andesite gravel, 10 percent cinder gravel, and 7 percent pumice paragravel; neutral (pH 6.6); gradual wavy boundary.
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 thick platy rocklike structure; hard, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; common distinct relict redoximorphic concentrations on surface of plates; 5 percent andesite gravel and 5 percent cinder gravel; slightly acid (pH 6.4); clear wavy boundary.
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; moderately acid (pH 6.4).
Typical Pedon Location
Map unit in which located: Unionpeak-Castlecrest-Sunnotch complex 0 to 15 percent slopes Location in park: About 1.5 miles southeast of Rim Drive junction, on the old east entrance road, and 700 feet north of road; 577216 meters easting and 4750353 meters northing, UTM Zone 10T, NAD 27; lat. 42o54’13.21″ N., long. 122o03’19.10″ W.
Range in Characteristics
Profile:
Depth to weakly cemented duripan—20 to 40 inches
Depth to bedrock—more than 60 inches
A horizon:
Value—2 or 3 moist, 3 to 5 dry
Chroma—2 or 3 moist or dry
Texture—ashy sandy loam or ashy loamy sand
Content of pumice paragravel—0 to 15 percent
Content of cinder gravel—0 to 10 percent
Content of andesite gravel—0 to 5 percent
Bw horizon:
Value—3 or 4 moist, 4 to 6 dry
Chroma—2 or 3 moist or dry
Texture—ashy loamy sand or ashy sandy loam
Content of pumice paragravel—0 to 10 percent
Content of cinder gravel—0 to 10 percent
Content of andesite gravel—0 to 5 percent
Bqm horizon:
Hue—5YR, 7.5YR, or 10YR
Value—3 or 4 moist, 4 or 5 dry
Chroma—2 or 3 moist or dry
Texture—ashy loamy sand or ashy sand
Dry consistence—hard in the upper part and slightly hard or soft in the lower part
Content of pumice paragravel—0 to 30 percent
Content of cinder gravel—0 to 25 percent
Content of andesite gravel—0 to 15 percent
Content of cinder cobbles—0 to 5 percent
Cementation—very weakly cemented or weakly cemented
C horizon:
Hue—5YR, 7.5YR, or 10YR
Value—3 or 4 moist, 4 or 5 dry
Chroma—2 or 3 moist or dry
Texture—ashy loamy sand or ashy sand
Content of pumice paragravel—0 to 30 percent
Content of cinder gravel—0 to 25 percent
Content of andesite gravel—0 to 15 percent
Content of cinder cobbles—0 to 5 percent
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