LOCATION PETROS TNEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, semiactive, mesic, shallow Typic Dystrudepts
TYPICAL PEDON: Petros channery silt loam with 20 percent slope on the nose slope of a ridgetop--forest. (Colors are for moist soil)
Oi--0 to 1 inches; very dark gray (10YR 3/1) partially decomposed organic mat of pine needles and hardwood leaves; very friable; strongly acid; abrupt smooth boundary.
A--1 to 2 inches; very dark gray (10YR 3/1) channery silt loam; weak fine granular structure; very friable; many medium and coarse roots; 20 percent shale fragments less than 3 inches in diameter; strongly acid; abrupt smooth boundary. (0 to 3 inches thick)
E--2 to 8 inches; brown (10YR 5/3) channery silt loam; moderate medium granular structure; friable; many fine and medium roots; 20 percent shale fragments less than 3 inches in diameter; strongly acid; clear wavy boundary. (3 to 8 inches thick)
Bw1--8 to 14 inches; yellowish brown (10YR 5/6) very channery silt loam; weak medium subangular blocky structure; friable; many medium and coarse roots; 40 percent shale and siltstone fragments ranging from 1 to 4 inches in diameter; strongly acid; gradual smooth boundary.
Bw2--14 to 19 inches; yellowish brown (10YR 5/6) very channery silt loam; weak medium and fine subangular blocky structure; friable; many fine and medium roots; 45 percent shale and siltstone fragments ranging from 1 to 6 inches in diameter; strongly acid; gradual wavy boundary. (Thickness of the Bw horizon ranges from 7 to 16 inches)
Cr--19 to 26 inches; interbedded soft shale and siltstone with yellowish brown silt loam coatings in cracks and between rock layers; strongly acid; clear smooth boundary. (6 to 12 inches thick)
R--26 inches; rippable shale bedrock.
TYPE LOCATION: Anderson County, Tennessee; 2 miles north of Fraterville on Vowell Mountain Road.
RANGE IN CHARACTERISTICS: Depth to soft shale or siltstone and thickness of the solum is 10 to 20 inches. Depth to shale bedrock is greater than 20 inches. Rock fragments, mostly channers, range from 15 to 35 percent in the A and E horizons and from 35 percent to 80 percent in the Bw horizon. Reaction is strongly acid or very strongly acid throughout.
The A horizon has hue of 10YR, value of 3 or 4, and chroma of 1 to 3. Fine-earth texture is silt loam or loam.
The E horizon has hue of 10YR, value of 4 to 6, and chroma of 2 to 4. Fine-earth texture is silt loam or loam.
The Bw horizon has hue of 10YR or 7.5YR, value of 4 to 6, and chroma of 4 or 6. Fine-earth texture is silt loam or silty clay loam.
The Cr horizon is weakly to moderately cemented shale and siltstone that can be excavated by hand tools and is commonly interbedded.
The R horizon is strongly cemented, but may be ripped by heavy equipment due to the interbedded nature of the parent materials and may be absent in some pedons.
COMPETING SERIES: The Cataska series is the only other member in this family. Cataska soils formed in material weathered from slate or phyllite and have more than 30 percent weatherable minerals such as chlorite, sericite, and hydrobiotite. Other soils in closely related families include the Berks, DeKalb, Litz, Montevallo, Muskingum, and Weikert series. Berks and DeKalb soils have sola greater than 20 inches thick. Litz soils have thin intermittent argillic horizons. Montevallo soils are in the thermic temperature regime. Muskingum soils have less than 35 percent coarse fragments and sola thicker than 20 inches. Weikert soils are less than 20 inches to hard bedrock.
GEOGRAPHIC SETTING: Petros soils are mostly on crests and summits of mountaintops or upper mountain side slopes in the Cumberland Plateau section of MLRA-125. Mean annual temperature is 55 degrees F. and average annual precipitation is 54 inches near the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bouldin, Gilpin, Jefferson, Lily, Ramsey, and Zenith series. Bouldin, Gilpin, Jefferson, and Lily soils have argillic horizons. Zenith soils have umbric epipedons. Gilpin and Lily soils are moderately deep; Jefferson and Zenith soils are deep; adn Bouldin soils are very deep. Bouldin, Jefferson, Lily, Ramsey, and Zenith soils have siliceous mineralogy.
DRAINAGE AND PERMEABILITY: Excessively drained with moderate or moderately rapid permeability.
USE AND VEGETATION: Practically all area are in forest. The forest consists mostly of Virginia pine and dry site hardwoods.
DISTRIBUTION AND EXTENT: The Cumberland Plateau in Tennessee and possibly Kentucky, Virginia, and West Virginia. Extent is moderate.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Anderson County, Tennessee; 1978.
REMARKS: Diagnostic horizons recognized in this pedon are:
Ochric epipedon - 1 to 8 inches (A and E horizon)
Cambic horizon - 8 to 19 inches (Bw horizon)
Paralithic contact - 19 to 26 inches (Cr horizon)
Lithic contact - 26 inches (R horizon)