LOCATION GILPIN PA+IN KY MD NC NY OH TN VA WVEstablished Series
The Gilpin series consists of moderately deep, well drained soils formed in residuum of nearly horizontal interbedded shale, siltstone, and some sandstone of the Allegheny Plateau. They are on gently sloping to steep, convex, dissected uplands. Slope ranges from 0 to 70 percent. Permeability is moderate. Mean annual precipitation is 43 inches, and mean annual air temperature is 51 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Typic Hapludults
TYPICAL PEDON: Gilpin channery silt loam on a 3 percent northwest facing slope in cropland. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 8 inches; dark grayish brown (10YR 4/2) channery silt loam; weak fine granular structure; friable, slightly sticky and slightly plastic; 20 percent rock fragments of subangular siltstone and shale; moderately acid; abrupt smooth boundary.(6 to 10 inches thick)
Bt1--8 to 13 inches; yellowish brown (10YR 5/4) channery silt loam; weak fine and medium subangular blocky structure; friable, slightly sticky and slightly plastic; few distinct clay films on faces of peds and in pores; 25 percent rock fragments of subangular siltstone and shale; moderately acid; gradual wavy boundary.
Bt2--13 to 24 inches; yellowish brown (10YR 5/6) channery silt loam; moderate medium subangular blocky structure; friable, slightly sticky and moderately plastic; few distinct clay films on faces of peds and in pores; 30 percent rock fragments of subangular siltstone and shale; very strongly acid; clear wavy boundary. (Combined thickness of the Bt horizon is 12 to 26 inches.)
C--24 to 30 inches; brown (10YR 5/3) extremely channery loam; massive; friable, slightly sticky and slightly plastic; few faint clay films and common prominent black coatings on fragments; 60 percent rock fragments of subangular siltstone and shale; very strongly acid; clear wavy boundary. (0 to 10 inches thick)
R--30 inches; light olive brown (2.5Y 5/4) fractured, thin bedded, shale and siltstone with silt and clay coatings in fractures; strongly acid.
TYPE LOCATION: Indiana County, Pennsylvania; North Mahoning Township, about l/2 mile southeast of Marchand, on hilltop 500 feet east of Township Road 660. U.S.G.S. Marion Center Topographic Quadrangle. Lat. 40 degrees, 51 minutes, 18 seconds, N. and Long. 79 degrees, 1 minute, 7 seconds W; NAD 1927.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 18 to 36 inches. Fractured, bedded and rippable bedrock is at depths of 20 to 40 inches. Rock fragments are mostly angular to subangular channers of shale, siltstone and sandstone and comprise 5 to 40 percent of individual horizons of the solum and 30 to 90 percent of the C horizon. The rock fragment content is less than 35 percent, by volume in the upper 20 inches of the argillic horizon. Reaction ranges from strongly to extremely acid throughout unless limed.
The Ap has hue of 10YR or 2.5Y with value of 3 to 5, and chroma of 2 to 4. Dry values are 6 or 7. The A horizon, where present, has hue of 10YR or 2.5Y with value of 2 to 4, and chroma of 1 to 3. Thickness for the A horizon ranges from 2 to 5 inches. The texture of the Ap or A horizon is silt loam or loam in the fine earth fraction.
Some pedons have E, BE, or BA horizons. These horizons range from 0 to 6 inches thick and have hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 5 to 3. Texture is silt loam or loam in the fine earth fraction.
The Bt horizon has hue of 7.5YR to 2.5Y, value of 4 to 6, and chroma of 4 to 8. Colors tend to become redder with depth. Textures are silt loam, loam, clay loam, or silty clay loam in the fine-earth fraction. Clay films on ped faces, pores and on rock fragments are few or common and faint or distinct.
Some pedons have a BC horizon with colors and textures similar to the C horizon.
The C horizon has hue of 7.5YR to 2.5Y, value of 3 to 5, and chroma of 2 to 6. Texture is silt loam, loam or silty clay loam in the fine-earth fraction.
Some pedons have a Cr horizon.
The R horizon is horizontal interbedded shale, siltstone or fine grained sandstone.
COMPETING SERIES: The Bedington, Clymer, Edgemont, Edneytown, Gladstone, Joana, Millstone, Pigeonroost, Rayne, Shelocta, Syenite and Wist (T) series are in the same family. Bedington, Clymer, Edgemont, Joanna, Rayne, Shelocta and Wist (T) soils have bedrock at more than 40 inches. Edneytown soils have a Cr horizon at more than 60 inches. Gladstone soils have granitic gneiss bedrock at 60 inches or more. Millstone soils have bedrock deeper than 80 inches. Pigeonroost soils have a Cr horizon within a 20 to 40 inch depth. Syenite soils have coarse fragments of granite in the control section.
The following series were competing under the old classification. They may compete after they are updated to the 9th Edition of Keys to Soil Taxonomy. The Albemarle, Arendtsville, Bucks, Butano, Chester, Elsinboro, Eubanks, Ezel, Freehold, Leedsville, Meadowville, Nixon, Pineville, and Quakertown competed under the old classification. Of these only Butano soils have bedrock at a depth of 20 to 40 inches. Bertano soils occur in the costal range of mountains of central eastern California with humid mesothermal climate.
GEOGRAPHIC SETTING: Gilpin soils are on nearly level to very steep, convex, dissected uplands with slopes of 0 to 70 percent. They developed in residuum weathered from nearly horizontal, interbedded gray and brown acid siltstone, shale and sandstone. The climate is humid temperate with an average annual rainfall of 36 to 50 inches, average annual air temperatures of 46 to 57 degrees F., and a growing season of 120 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Berks, Blairton, Clymer, Dekalb, Muskingum, Rayne, Shelocta, Upshur, Weikert, Wellston, Westmoreland and Wharton soils. Blairton, Cavode, Ernest and Wharton soils have redoximorphic features in the subsoil. Berks and Muskingum soils do not have argillic horizons. Shelocta, Rayne and Wellston soils are more than 40 inches to rock. Upshur soils have finer textures. Weikert soils have bedrock at 20 inches or less.
DRAINAGE AND PERMEABILITY: Well drained. The potential for surface runoff is negligible to high. The permeability is moderate.
USE AND VEGETATION: Gilpin soils are mainly used for cropland and pasture. Wooded areas are in mixed hardwoods, mainly oaks.
DISTRIBUTION AND EXTENT: Pennsylvania, West Virginia, Ohio, Kentucky, Maryland, New York, North Carolina, Tennessee, Virginia and Indiana. The series is of large extent.
MLRA OFFICE RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Indiana County, Pennsylvania, 1931.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
a. Ochric epipedon - the zone from the surface of the soil to a depth of 8 inches (Ap
horizon).
b. Argillic horizon - the zone from 8 to 24 inches (Bt horizon).
The clay mineralogy is mixed, with illite dominant and kaolinite and vermiculite in lesser quantities.
This series is mapped extensively in many states and MLRA's. Data available indicates CEC of superactive, active, and semiactive. Weighted average supports a CEC of active.
ADDITIONAL DATA: Characterization sample S61PA-32-56 is from Type Location, and was used as the basis for placing this series in the active CEC class. Also available is S61PA-32-54.