LOCATION CHAOS CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, nonacid, frigid Typic Xerorthents
TYPICAL PEDON: Chaos extremely gravelly ashy coarse sand, on a west facing (250 degrees) slope of 6 percent, under a cover of Jeffery pine, lodgepole pine, western white pine and white fir at an elevation of 5963 feet, (1809 m). When described on 10/4/07, the soil was dry throughout. Colors are for dry soil unless otherwise noted.
Oi--0 to 0.4 inches (0 to 1 cm); pine needles and twigs; abrupt smooth boundary.
A--0.4 to 4 inches (1 to 9 cm); light brownish gray (10YR 6/2) extremely gravelly ashy coarse sand, dark grayish brown (10YR 4/2) moist; 1 percent clay; single grain; many very fine and fine and few medium roots; many very fine and fine interstitial pores; 22 percent angular fine gravel and 50 percent angular medium and coarse gravel; strongly acid, pH 5.3 by pH meter 1:1 water; NaF pH 7.9; clear smooth boundary. (2 to 6 inches (5 to 15.5 cm) thick)
AC--4 to 9 inches (9 to 23 cm); pinkish gray (7.5YR 6/2) gravel, brown (7.5YR 4/2) moist; 1 percent clay; single grain; many very fine to medium roots; many very fine and fine and few medium interstitial pores; 10 percent angular fine gravel, 75 percent angular medium and coarse gravel, and 5 percent angular cobbles; slightly acid, pH 6.3 by pH meter 1:1 water; NaF pH 8.8; abrupt wavy boundary. (3 to 7 inches (7.5 to 18 cm) thick)
C1--9 to 21 inches (23 to 53 cm); white (10YR 8/1) extremely gravelly ashy coarse sand, grayish brown (10YR 5/2) moist; 1 percent clay; single grain; common very fine to medium, and many coarse and very coarse roots; common very fine and fine interstitial pores; 14 percent angular fine gravel, 50 percent angular medium and coarse gravel, and 10 percent angular cobbles; slightly acid, pH 6.1 by pH meter 1:1 water; NaF pH 9.0; abrupt wavy boundary.
C2--21 to 23 inches (53 to 59 cm); pink (7.5YR 7/3) gravelly ashy sandy loam, brown (7.5YR 4/3) moist; 4 percent clay; weak fine subangular blocky structure parting to single grain; few very fine and fine, many medium and coarse, and few very coarse roots; common fine vesicular and many very fine and fine interstitial pores; 10 percent subangular fine gravel and 10 percent subangular medium and coarse gravel; moderately acid, pH 6.0 by pH meter 1:1 water; NaF pH 9.8 abrupt wavy boundary.
C3--23 to 27 inches (59 to 68 cm); pinkish gray (7.5YR 6/2) very gravelly ashy loamy coarse sand, brown (7.5YR 4/2) moist; 2 percent clay; massive; few very fine to medium roots; many very fine interstitial, and common fine tubular and vesicular pores; 15 percent subangular fine gravel and 30 percent subangular medium and coarse gravel; slightly acid, pH 6.4 by pH meter 1:1 water;, NaF pH 8.6; abrupt wavy boundary.
C4--27 to 36 inches (68 to 92 cm); light reddish brown (2.5YR 7/3) gravelly ashy loamy coarse sand, reddish brown (2.5YR 5/4) moist; 2 percent clay; massive; common very fine, and few fine and medium roots; common very fine interstitial and many fine vesicular pores; 13 percent subangular fine gravel, 13 percent subangular medium and coarse gravel, and 3 percent subangular cobbles; slightly acid, pH 6.3 by pH meter 1:1 water; NaF pH 9.0; abrupt smooth boundary.
C5--36 to 56 inches (92 to 142 cm); light gray (10YR 7/1) very gravelly ashy loamy coarse sand, gray (10YR 5/1) moist; 3 percent clay; massive; nonsticky, nonplastic; common very fine and few fine and medium roots; common fine vesicular, and many very fine and fine and common medium interstitial pores; 12 percent subangular fine gravel, 20 percent subangular medium and coarse gravel, and 20 percent subangular cobbles; slightly acid, pH 6.5 by pH meter 1:1 water; NaF pH 8.9; clear smooth boundary.
C6--56 to 75 inches (142 to 191 cm); light gray (7.5YR 7/1) extremely gravelly ashy loamy coarse sand, dark gray (7.5YR 4/1) moist; 4 percent clay; massive; few very fine and fine and common medium roots; many very fine and fine interstitial, and common fine and few medium vesicular pores; 20 percent subangular fine gravel, 35 percent subangular medium and coarse gravel, and 7 percent subangular cobbles; neutral, pH 6.8 by pH meter 1:1 water; NaF pH 8.8; abrupt smooth boundary.
C7--75 to 87 inches (191 to 220 cm); pinkish gray (5YR 6/2) gravelly ashy loamy sand, dark reddish gray (5YR 4/2) moist; 0 percent clay; massive; few very fine roots throughout; many very fine and fine interstitial and few fine vesicular pores; 16 percent subangular fine gravel and 16 percent subangular medium and coarse gravel; slightly acid, pH 6.5 by pH meter 1:1 water; NaF pH 8.2; HORIZON NOTE: Has weathered porous gravel. (Combined thickness of the C horizon is 75 to 82 inches (190.5 to 208 cm) thick)
TYPE LOCATION: Shasta County, California, about 700 feet southeast of Lily Pond, approximately 800 feet west and 2100 feet south of the northeast corner of sec 18, T. 31 N, R. 4 E, 40 degrees, 32 minutes, 16 seconds north latitude and 121 degrees, 33 minutes, 41 seconds west longitude, NAD83; USGS Quad: Manzanita Lake, California.
RANGE IN CHARACTERISTICS:
Depth to restrictive feature: Bedrock greater than 60 inches, (152 cm)
Mean annual soil temperature: 43 to 47 degrees F (6 to 8 degrees C).
Soil moisture control section is dry: June to November (about 180 days).
Particle-size control section (weighted average): 0 to 2 percent clay, and 27 to 83 percent rock fragments.
Surface fragments: 15 to 60 percent gravel, 10 to 70 percent cobbles, 2 to 50 percent stones, and 0 to 50 percent boulders.
A horizon:
Color dry: 10YR 6/1, 6/2
Color moist: 10YR 3/2, 4/2
Texture: gravelly ashy coarse sand, very gravelly ashy coarse sand, extremely gravelly ashy coarse sand
Clay content: 0 to 1 percent
Rock fragments: 8 to 22 percent fine gravel, 4 to 50 percent medium and coarse gravel, 12 to 72 percent total gravel, 0 to 5 percent cobbles, 0 to 3 percent stones, 0 to 3 percent boulders, 17 to 72 percent total rock fragments
Organic matter: 1 to 4.5 percent
Base saturation by ammonium acetate: 38 to 50 percent
Acid oxalate extractable Al plus 1/2 Fe: 0.05 to 0.11
P retention: 1 to 8 percent
Glass content: 12 to 18 percent
NaF pH: 7.9 to 9.7
Soil reaction: strongly acid to slightly acid
AC horizon:
Color dry: 10YR 7/1, 7/2, 7.5YR 6/2
Color moist: 10YR 3/2, 7.5YR 4/2
Texture: gravel, extremely gravelly ashy coarse sand, extremely gravelly ashy sand, extremely cobbly ashy sand, extremely cobbly ashy coarse sand, ashy gravel
Clay content: 0 to 1 percent
Rock fragments: 5 to 10 percent fine gravel, 30 to 75 percent medium and coarse gravel, 35 to 85 percent total gravel, 5 to 45 percent cobbles, 0 to 5 percent stones, 0 to 5 percent boulders, 70 to 92 percent total rock fragments
Organic matter: 0.5 to 1.5 percent
Base saturation by ammonium acetate: 50 to 65 percent
Acid oxalate extractable Al plus 1/2 Fe: 0.02 to 0.10
P retention: 1 to 8 percent
Glass content: 5 to 15 percent
NaF pH: 8.8 to 9.5
Soil reaction: slightly acid
C horizons:
Color dry: 2.5YR 7/3, 5YR 6/2, 7.5YR 6/2, 7/1, 7/3, 8/1, 10YR 6/2, 7/1, 7/2, 7/3, 8/1
Color moist: 2.5YR 5/4, 5YR 4/2, 7.5YR 4/1, 4/2, 4/3, 5/2, 10YR 4/2, 5/1, 5/2, 6/2
Texture: gravelly ashy loamy sand, gravelly ashy loamy coarse sand, gravelly ashy sandy loam, very gravelly ashy sand, very gravelly ashy loamy sand, very gravelly ashy loamy coarse sand, extremely gravelly ashy loamy coarse sand, extremely gravelly ashy coarse sand, very cobbly ashy loamy sand, very cobbly ashy loamy coarse sand, extremely cobbly ashy loamy sand
Clay content: 0 to 4 percent
Rock fragments: 5 to 20 percent fine gravel, 7 to 50 percent medium and coarse gravel, 14 to 64 percent total gravel, 3 to 45 percent cobbles, 0 to 30 percent stones, 0 to 5 percent boulders, 20 to 90 percent total rock fragments
Organic matter: 0 to 0.5 percent
Base saturation by ammonium acetate: 22 to 100 percent
Acid oxalate extractable Al plus 1/2 Fe: 0 to 0.20
P retention: 1 to 28 percent
Glass content: 8 to 20 percent
NaF pH: 8.2 to 10.5
Soil reaction: moderately acid to neutral
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Chaos soils are on rockfall avalanches from Chaos Crags. Slopes are 2 to 30 percent. These soils formed in rockfall avalanche deposits from rhyodacite domes. Elevation is 5756 to 7200 feet (1755 to 2195 m). Mean annual precipitation is 39 to 93 inches (991 to 2362 mm). The mean annual temperature is 40 to 45 degrees F (4.5 to 7 degrees C). Frost free season is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cragwash and Sueredo soils. The Cragwash soils are deep to a duripan and are on glacial outwash plains. The Sueredo soils are very deep to dense till and are on moraines.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; saturated hydraulic conductivity is very high in the A horizon, and high to very high in the AC and C horizons.
USE AND VEGETATION: This soil is used for wildlife habitat, recreation, ecosystem management and watershed. Vegetation is Jeffery pine, lodgepole pine, western white pine white fir, California red fir, pinemat manzanita, buckwheat, and snowbrush ceanothus.
DISTRIBUTION AND EXTENT: The soils are inextensive and are mapped in MLRA: 22B, Southern Cascade Mountains.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Shasta County, California 2008. Source of name from Chaos Jumbles, the primary rockfall avalanche where this soil is found.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0.4 to 9 inches, (1 to 23 cm)
Particle-size control section: 10 to 40 inches, (26 to 101 cm)
Soil moisture control section: 39 to greater than 87 inches, (98 to greater than 220 cm)
ADDITIONAL DATA: Characterization data from lab pedon number 08N0102 NSSL, Lincoln, NE. NASIS User Pedon ID in Davis, MLRA Office: 789359.