LOCATION ROCK RESERVOIR          WY

Tentative Series
IRD. IGC-JCK
03/2017

ROCK RESERVOIR SERIES

The Rock Reservoir series consist of very deep, very poorly drained soils that formed in alluvium. These soils are on flood plains. Slopes are from 0 to 4 percent. Mean annual precipitation is about 191 mm, and mean annual air temperature is about 8 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous, mesic Aeric Fluvaquents

TYPICAL PEDON: Rock reservoir sandy loam, 1 percent slope in rangeland at an elevation of 1,439 meters. (Colors are for moist soil unless otherwise noted.)

A1--0 to 12 cm; dark grayish brown (10YR 4/2) sandy loam, yellowish brown (10YR 5/4) moist; weak fine granular structure; loose; nonsticky and nonplastic; many very fine roots throughout; few very fine vesicular pores; 2 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (8 to 15 cm thick)

AC--12 to 18 cm; brown (10YR 4/3) loam, brown (10YR 5/3) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots throughout, few very fine dendritic tubular pores; 2 percent gravel; slightly effervescent; slightly alkaline (pH 7.6); clear smooth boundary. (0 to 15 cm thick)

C1--18 to 26 cm; dark grayish brown (10YR 4/2) fine sandy loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots throughout, few very fine dendritic tubular pores; 5 percent fine 7.5YR 6/6 oxidized iron masses; 2 percent gravel; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary.

C2--26 to 52 cm; dark grayish brown (10YR 4/2) loam, grayish brown (10YR 5/2) moist; massive; soft, very friable, nonsticky and nonplastic, few very fine roots throughout; 3 percent fine 7.5YR 5/6 oxidized iron masses, 10 percent fine 2.5Y 6/1 iron depletions; 5 percent gravel; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (combined thickness of C1 and C2 horizons is 20 to 60 cm)

C3--52 to 200 cm; dark grayish brown (10YR 4/2) gravelly sandy loam, grayish brown (10YR 5/2) moist; single grain; loose; nonsticky and nonplastic, 2 percent fine 7.5YR 5/6 oxidized iron masses, 20 percent fine 2.5Y 6/1 iron depletions; 15 percent gravel and 10 percent cobbles; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary.

TYPE LOCATION: Park County, Wyoming; 703 meters south and 198 meters east of the northwest corner of section 24, T. 52 N., R. 98 W.; YU Bench NE USGS quadrangle; latitude 44 degrees 27 minutes 58.36 seconds N. and longitude 108 degrees 35 minutes 28.93 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 8 to 10 degrees C
Depth to seasonal high water table - 0 to 30 cm


A and AC horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3 or 4
Texture: sandy loam, loam, or fine sandy loam
Clay content: 12 to 20 percent
Rock fragments: 0 to 15 percent gravel or cobbles
Reaction: 7.2 to 7.8

C1 and C2 horizons
Hue: 10YR to 2.5Y
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3
Texture: fine sandy loam, loam or sandy loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 15 percent gravel or cobbles
Reaction: 7.6 to 8.2

C3 horizon
Hue: 10YR to 2.5Y
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3
Texture: fine sandy loam or sandy loam
Clay content: 8 to 15 percent
Rock fragments: 15 to 35 percent: 15 to 35 percent gravel; 0 to 15 percent cobbles
Reaction: 7.6 to 8.2

COMPETING SERIES:
Bigwinder (WY) - contain layers with more than 85 percent sand throughout the particle-size control section; do not have rock fragments
Mirada (NM) - have horizons of strong gley; contain layers with more than 50 percent silt in the upper part of the subsoil
Tweba (NM) - have more than 50 percent silt in the upper part of the subsoil; are strongly and very strongly alkaline throughout the subsoil

GEOGRAPHIC SETTING:
Landform - flood plains
Elevation - 1,085 - 1,500 meters
Slope - 0 to 4 percent slopes
Parent material - alluvium
Mean annual precipitation - 127 to 229 mm
Mean annual air temperature - 6 to 8 degrees C
Frost-free period - 110 to 150 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Very poorly drained; moderately rapid permeability.

USE AND VEGETATION: Rock reservoir soils are used for wildlife and livestock grazing. Native vegetation is alkali cordgrass, alkali sacaton, inland saltgrass, slender wheatgrass, American licorice, greasewood and yellow rabbitbrush.

DISTRIBUTION AND EXTENT: Rock reservoir soils are of small extent in northwestern Wyoming. MLRA 32.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED: Park County Area, Wyoming, Eastern Part, 2016. The name is taken from a local landform.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 18 cm (A horizon)
Redoximorphic concentrations - from 18 to 200 cm (C1, C2 and C3 horizons)
Redoximorphic depletions - from 26 to 200 cm (C2 and C3 horizons)
Particle-size control section - from 25 to 100 cm (part of the C1, C2 and C3 horizons)

Rock Reservoir soils have a mesic temperature regime and an aquic moisture regime.

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National Cooperative Soil Survey
U.S.A.