LOCATION ROCKCREEK               CA

Established Series
CES/JBB
09/2021

ROCKCREEK SERIES

The Rockcreek series consists of very deep, poorly drained soils formed in organic material over alluvium, slope alluvium, colluvium, and till derived from granitic and metamorphic rocks. The Rockcreek soils are on seeps of mountain slopes, glacial-valley floors, and glacial-valley walls of the Sierra Nevada Mountains. Slopes range from 5 to 30 percent. The mean annual precipitation is about 800 mm and the mean annual air temperature is about 3 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, isotic Histic Cryaquepts

TYPICAL PEDON: Rockcreek muck on a north-facing (4 degree), 25 percent slope under Lemmon's willow and Sierra lodgepole pine at an elevation of 3063 meters. (Colors are for dry soils unless otherwise noted. When described on July 7, 2015 the soil was wet, nonsatiated to 120 cm, and wet, satiated from 120 to 165 cm. Water table was observed at 120 cm.)

Oa--0 to 26 cm; black (10YR 2/1) muck, black (7.5YR 2.5/1) moist; many very fine and common fine roots throughout; common very fine irregular pores; NaF pH 7.5; moderately acid (pH 5.6); abrupt wavy boundary.

AC--26 to 29 cm; dark gray (10YR 4/1) mucky coarse sand, black (10YR 2/1) moist; 1 percent clay; structureless single grain; loose, loose, slightly sticky, nonplastic; many very fine and common fine roots throughout; common very fine interstitial pores; 7 percent subrounded indurated granite gravel; NaF pH 8.0; strongly acid (pH 5.3); abrupt smooth boundary.

Oab--29 to 40 cm; very dark gray (10YR 3/1) muck, black (10YR 2/1) moist; common very fine and fine roots throughout; few very fine irregular pores; NaF pH 10.0; strongly acid (pH 5.5); abrupt wavy boundary. (Combined thickness of Oa and Oab horizons is 5 to 40 cm)

C--40 to 69 cm; dark grayish brown (10YR 4/2) gravelly coarse sand, very dark grayish brown (10YR 3/2) moist; 0 percent clay; structureless massive; loose, very friable, nonsticky, nonplastic; common very fine and fine roots throughout; common very fine interstitial pores; 1 percent medium prominent irregular masses of oxidized iron in matrix and 12 percent medium prominent irregular masses of oxidized iron at top of horizon; 20 percent subrounded indurated granite gravel, 2 percent subangular indurated granite cobbles, 5 percent subangular indurated granite stones; NaF pH 8.0; slightly acid (pH 6.1); clear smooth boundary.

Ab--69 to 75 cm; very dark gray (10YR 3/1) mucky coarse sand, black (10YR 2/1) moist; 2 percent clay; structureless massive; loose, very friable, slightly sticky, nonplastic; common very fine roots throughout; common very fine interstitial pores; 20 percent subrounded indurated granite gravel; NaF pH 8.0; moderately acid (pH 5.7); clear smooth boundary. (Combined thickness of AC and Ab horizons is 0 to 10 cm)

C'1--75 to 120 cm; grayish brown (10YR 5/2) very gravelly coarse sand, dark grayish brown (10YR 4/2) moist; 0 percent clay; structureless single grain; loose, loose, nonsticky, nonplastic; common very fine roots throughout; common very fine interstitial pores; 1 percent medium faint irregular iron depletions and 3 percent medium prominent irregular masses of oxidized iron in matrix; 35 percent subrounded indurated granite gravel, 3 percent subangular indurated granite cobbles; NaF pH 8.0; slightly acid (pH 6.2); gradual smooth boundary. (Combined thickness of C horizons is 75 to 120 cm)

C'2--120 to 165 cm; very pale brown (10YR 7/3) very gravelly coarse sand, brown (10YR 5/3) moist; 0 percent clay; structureless single grain; loose, loose, nonsticky, nonplastic; common very fine interstitial pores; 40 percent fine prominent irregular masses of reduced iron in matrix; 50 percent subrounded indurated granite gravel, 3 percent subangular indurated granite cobbles; NaF pH 8.5; slightly acid (pH 6.5).

TYPE LOCATION: Tulare County, California, near Cottonwood/Siberian Pass Trail fork; USGS 7.5 minute topographic quadrangle: Johnson Peak, California; WGS84 36.491119 latitude and -118.322228 longitude; UTM zone 11 4039236 meters N 381571 meters E WGS84.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature at 50 cm is 0 to 6 degrees C and the difference between mean summer and mean winter soil temperature is more than 6 degrees C. The soils have a cryic temperature regime.

Soil moisture: The soil is saturated in some part throughout the year, with a seasonal high water table dropping below 50 cm in late summer and fall. The soils have an aquic soil moisture regime.

Diagnostic Feature(s):
Histic epipedon thickness: 20 to 40 cm
Aquic conditions: present within 25 cm of soil surface

Organic matter: 20 to 60 percent in the epipedon

Base saturation: less than 50 percent in the epipedon (by ammonium acetate)

Depth to redoximorphic features: 20 to 50 cm


Particle size control section weighted average:

Rock fragments: 35 to 80 percent, with 5 to 60 percent gravel, 0 to 35 percent cobbles, 0 to 15 percent channers, 0 to 15 percent stones and 0 to 15 percent flagstones.
Clay content: 0 to 6 percent
NaF pH: 8.0 to 11.0

Oa or Oab horizon(s)
Hue: 7.5YR, 10YR
Value: 2 or 3 dry, 1 moist
Chroma: 1 or 2, dry or moist
Texture: muck
Rock fragments: 0 to 35 percent
0 to 5 percent gravel
0 to 5 percent cobbles
0 to 15 percent channers
0 to 15 percent stones
0 to 15 percent flagstones
0 to 10 percent boulders
Reaction: moderately acid to slightly acid

A, Ab, or AC horizon(s)(where present)
Hue: 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 to 3 dry, 1 or 2 moist
Texture: coarse sand, loamy coarse sand, loamy sand, sandy loam
Clay content: 0 to 10 percent
Rock fragments: 5 to 35 percent
5 to 35 percent gravel
0 to 15 percent channers
0 to 5 percent cobbles
0 to 15 percent stones
0 to 15 percent flagstones
0 to 10 percent boulders
Reaction: strongly acid to slightly acid

C horizon(s)
Hue: 10YR
Value: 4 to 7 dry, 3 to 5 moist
Chroma: 2 to 4, dry or moist
Texture: coarse sand, loamy coarse sand
Clay content: 0 to 5 percent
Rock fragments: 15 to 80 percent
15 to 60 percent gravel
0 to 5 percent channers
0 to 35 percent cobbles
0 to 5 percent stones
0 to 5 percent flagstones
Redoximorphic Features:
Oxidized iron masses in matrix
Quantity: none to common
Size: medium
Iron depletions in matrix
Quantity: none to many
Size: fine
Reaction: strongly acid to slightly acid


Cg horizon(s) (where present)
Hue: 10YR, 2.5Y
Value: 7 dry, 5 or 6 moist
Chroma: 1 dry, 2 moist
Texture: sandy loam, fine sandy loam
Clay content: 5 to 10 percent
Rock fragments: 15 to 35 percent
5 to 15 percent gravel
0 to 35 percent channers
0 to 35 percent cobbles
0 to 15 percent flagstones
Redoximorphic Features:
Oxidized iron masses in matrix
Quantity: none to common
Size: fine and medium
Iron depletions in matrix
Quantity: none to common
Size: medium
Reaction: slightly to strongly acid

COMPETING SERIES: These are the Ladderlake soils. Ladderlake soils have Bw horizons, are on flood-plain steps with 0 to 4 percent slopes, and undergo occasional to frequent ponding for long duration.

GEOGRAPHIC SETTING: The Rockcreek soils are on seeps of mountain slopes, glacial-valley floors, and glacial -valley walls. Slopes range from 5 to 30 percent. These soils formed in organic material over alluvium, slope alluvium, colluvium, and till derived from granitic and metamorphic rocks. Elevation is 2450 to 3615 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 530 to 1455 mm and the mean annual air temperature is -1 to 5 degrees C. The frost free season is 50 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Benchlake and Forgotten soils. The Benchlake soils are well drained soils on structural benches of mountain slopes and glacial-valley walls, have an ochric epipedon, and are shallow to lithic contact. The Forgotten soils are moderately well drained soils on high-gradient drainageways on mountain slopes and glacial valley walls, and have an umbric epipedon.

DRAINAGE AND PERMEABILITY: Poorly drained, high to very high saturated hydraulic conductivity. Occasional flooding for very brief to brief (4 hrs to 7 days) duration from May to July. Seasonal high water table at 25 to 100 cm.

USE AND VEGETATION: This soil is used for recreation, wildlife habitat, and watershed. Vegetation is Sierra and Lemmon's willow, shootingstar, Carex species, assorted perennial grasses, and scattered Sierra lodgepole pine.

DISTRIBUTION AND EXTENT: Sierra Nevada Mountains of California; MLRA 22A. These soils are of limited extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES PROPOSED: Tulare County, California in Sequoia and Kings Canyon National Parks. Source of name from Rock Creek in Sequoia National Park.

REMARKS:
Particle Size Control Section for this pedon: 51 to 126 cm
Diagnostic horizons and features recognized in this pedon are:
Histic Epipedon 0 to 26 cm
Redox Concentrations 40 to 164 cm
Redox Depletions With Chroma 2 Or Less 75 to 120 cm

ADDITIONAL DATA:
NASIS User Pedon ID: 2015CA7923050

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

---

National Cooperative Soil Survey
U.S.A.