LOCATION PEANUTROCK         AR
Established Series
JWO:AMR:RKR
06/2010

PEANUTROCK SERIES


The Peanutrock series consists of very deep, well drained, moderately permeable soils that formed in loamy and gravelly marine sediments of Cretaceous age. These soils are on nearly level to steep marine terraces and uplands in the Cretaceous Western Gulf Coastal Plain Major Land Resource Area, MLRA 135B. Slopes are 1 to 35 percent.

TAXONOMIC CLASS: Loamy-skeletal, siliceous, semiactive, thermic Typic Hapludults

TYPICAL PEDON: Peanutrock very gravelly fine sandy loam, 1 to 8 percent slopes, in forest.(Colors are for moist soil unless otherwise stated.)

A--0 to 10 cm (0 to 4 in); very dark grayish brown (10YR 3/2) very gravelly fine sandy loam; weak medium granular structure; very friable; about 45 percent by volume sandstone gravel; slightly acid; clear wavy boundary.

E--10 to 25 cm (4 to 10 in); light yellowish brown (10YR6/4) very gravelly fine sandy loam; weak fine subangular blocky structure; friable; about 50 percent by volume sandstone and novaculite gravel (40%) and cobbles (10%); strongly acid; gradual wavy boundary.

Bt--25 to 84 cm (10 to 33 in); strong brown (7.5YR 5/6) very gravelly loam, moderate fine and medium subangular blocky structure; friable; common faint patchy clay films on ped faces and lining some pores; about 55 percent by volume sandstone gravel (45%) and cobbles (10%); strongly acid; gradual wavy boundary.

BC--84 to 203 cm (33 to 80 in); reddish yellow (7.5YR 6/6) extremely gravelly loamy sand; structureless; massive; about 70 percent by volume sandstone gravels (55%) and cobbles (15%); very strongly acid.

TYPE LOCATION: Pike County, Arkansas; SE14, SW1/4, SW1/4 Section. 29, T.8 S., R.24 W.; DELIGHT USGS topographic quadrangle; Latitude: 34 degrees, 1 minutes, 30 seconds North; Longitude: 93 degrees, 34 minutes, 30 seconds West.

RANGE IN CHARACTERISTICS: Solum thickness is more than 80 inches. Reaction ranges from slightly acid to strongly acid in the A horizon; slightly acid to very strongly acid in the E and BE horizons; medium acid to very strongly acid in the Bt horizons; and strongly acid to extremely acid in the BC or C horizons.
Coarse fragments range from 15 to 60 percent by volume in the A, E, and BE horizons; 35 to 60 percent in the upper Bt horizon(s); and 35 to 80 percent in the lower Bt horizons; and 60 to 80 percent in the BC or C horizons. In some pedons, the lower Bt, BC and C horizons consist of gravels and cobbles of sandstone and/or chert and novaculite that are weakly to strongly cemented by iron, gypsum, calcite, dried clay binder, or a tuffaceous material. Typically, the cementation is a yellowish color in the tuffaceous material and red or brown in the other materials. This cementation can occur in layers of varying thicknesses and, in some pedons, there is horizon stratification with strongly contrasting particle and fragment sizes.

A horizon:
Hue: of 10YR
Value: 3 or 4
Chroma: 2 to 4
Texture: very gravelly fine sandy loam.

E horizon:
Hue: 10YR
Value: 4, 5, or 6
Chroma: 3 or 4
Texture: gravelly fine sandy loam, gravelly sandy loam, gravelly loam, gravelly loamy sand, gravelly silt loam (rare) or their very gravelly analogs.

BE horizon (where present):
Hue: 7.5YR or 10YR
Value: 5
Chroma: 6 or 8
Texture: gravelly fine sandy loam, gravelly sandy loam, gravelly loam, gravelly loamy sand, gravelly silt loam (rare), or their very gravelly analogs.

Upper Bt horizon(s):
Hue: 7.5YR, 5YR, or 10YR,
Value: 4, 5, or 6
Chroma: 6 or 8
or Hue: 2.5YR
Value: 4 or 5
Chroma: 6 or 8.
Texture: very gravelly loam, very gravelly clay loam, very gravelly sandy clay loam, very gravelly sandy loam, or very gravelly silt loam (rare).

Lower Bt horizon(s):
Same colors as the upper Bt horizons . Some pedons may not have a dominant matrix color, but are variegated in shades of brown, red, and gray.
Texture: very gravelly loam, very gravelly clay loam, very gravelly sandy clay loam, very gravelly sandy loam, very gravelly silt loam (rare) or their extremely gravelly analogs.

BC horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5
Chroma: 6 or 8
In some pedons, this horizon is variegated in shades of brown, red, and gray.
Texture: very gravelly loam, very gravelly sandy clay loam, very gravelly sandy loam, very gravelly silt loam (rare) or their extremely gravelly analogs.

C horizon (where present):
Same color range as the BC horizon.
Texture: extremely gravelly fine sandy loam, extremely gravelly loam, extremely gravelly sandy loam, extremely gravelly sandy clay loam, or their very cobbly or extremely cobbly analogs.

COMPETING SERIES: These are the Avant, Bigfork, Cobstone, Lillington, Saffell, Steprock, Subligna, and Zafra series.
Avant soils have 20 to 40 inch sola over hard, fractured, tilted and folded, chert bedrock.
Bigfork soils have 20 to 50 inch sola over hard chert or novaculite that is tilted 20 degrees to 60 degrees from the horizontal.
Cobstone soils developed in fluvial sediments; typically have browner hues in the argillic horizon and coarse fragments are dominantly cobbles and stones.
Lillington soils developed in fluvial sediments and have sola more than 60 inches thick.
Saffell soils formed over Tertiary-aged sediments and are less stratified.
Steprock soils have 20 to 40 inch sola over weathered and hard sandstone bedrock.
Subligna soils developed in fluvial sediments and typically have browner hues in the argillic horizon.
Zafra soils have 20 to 56 inch sola over soft and hard interbedded sandstone and shale bedrock that is tilted 20 degrees to 60 degrees from the horizontal.

GEOGRAPHIC SETTING: Peanutrock soils are on marine terraces and uplands of the Cretaceous Western Gulf Coastal Plain, MLRA 135B and in the transitional area to the Ouachita Mountains, MLRA 119. They formed in loamy and gravelly marine sediments. Slopes range from 1 to 35 percent. Mean annual precipitation ranges from 45 to 55 inches. Mean annual temperature ranges from 63 degrees to 75 degrees F. Thornthwaite annual P-E indices are greater than 64.

GEOGRAPHICALLY ASSOCIATED SOILS: These are competing Nathan, Pikecity, and Tiak soils.
Nathan soils have a fine-silty control section.
Pikecity soils have a fine-loamy control section.
Tiak soils have a fine control section and is moderately well drained

DRAINAGE AND PERMEABILITY: Peanutrock soils are well drained. Runoff is low to rapid depending on slope, and permeability is moderate.

USE AND VEGETATION: Used mainly for native pasture and woodland. The vegetation is primarily southern red oak, sweetgum, American sycamore, white oak, and loblolly pine.

DISTRIBUTION AND EXTENT: Cretaceous Western Gulf Coastal Plain of southwest Arkansas and possibly southeast Oklahoma. The series is expected to be extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia

SERIES ESTABLISHED: Pike County, Arkansas; 2006

REMARKS: These soils were formerly included in the Saffell series.
Diagnostic features and subsurface features in this pedon are:
Ochric epipedon--surface to a depth of 25 cm (0 to 10 in)
Argillic horizon---zones from 25 to 84 cm (10 to 33 in)

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National Cooperative Soil Survey
U.S.A.