LOCATION THURMONT VA+GA MD NC PA WVEstablished Series
TYPICAL PEDON: Thurmont loam - forested. (Colors are for moist soil.)
0i--0 to 2 inches; partially decomposed and fresh leaves twigs of deciduous trees.
0e--2 to 4 inches; very dark gray partially decomposed organic matter.
A--4 to 5 inch; dark yellowish brown (10YR 4/4) loam; moderate fine granular structure; very friable; many fine and medium roots; 2 percent rounded and angular gravel; strongly acid; clear abrupt boundary. (1 to 6 inches thick)
E--5 to 13 inches; yellowish brown (10YR 5/6) loam; weak fine and very fine granular structure; very friable; many fine and medium roots; 2 percent rounded and angular gravel and cobblestones; very strongly acid; clear smooth boundary. (0 to 10 inches thick)
Bt1--13 to 18 inches; strong brown (7.5YR 5/6) clay loam; weak fine subangular blocky structure; friable, slightly sticky, slightly plastic; many fine and medium roots; few fine and medium pores; few thin clay films on faces of peds; common rounded and angular gravel and cobblestones; very strongly acid; clear smooth boundary.
Bt2--18 to 34 inches; strong brown (7.5YR 5/8) clay loam; moderate medium subangular blocky structure; friable, slightly sticky, slightly plastic; common fine roots; few fine and medium pores; few distinct clay films on faces of peds; 10 percent rounded and angular gravel and cobblestones; very strongly acid; clear smoth boundary.
Bt3--34 to 40 inches; strong brown (7.5YR 5/6) clay loam; few medium distinct yellowish red (5YR 5/6) and red (2.5YR 4/8) mottles; moderate medium subangular blocky structure; firm, sticky, slightly plastic; few fine roots; few fine and medium pores; common distinct clay films on faces of peds; 10 percent rounded and angular cobblestones; very strongly acid; gradual smooth boundary.
Bt4--40 to 52 inches; yellowish red (5YR 4/6) sandy clay loam; common medium distinct red (2.5YR 4/8), strong brown (7.5YR 5/8) masses of iron accumulation, and grayish brown (2.5Y 5/2) iron depletions; weak coarse subangular blocky structure; friable, slightly sticky, slightly plastic; few fine roots; few fine pores; few distinct clay films on faces of peds; 10 percent rounded and angular cobblestones; very strongly acid; gradual smooth boundary. (combined thickness of Bt horizon is 20 to 50 inches)
C1--52 to 64 inches; strong brown (7.5YR 5/6) cobbly sandy loam; many coarse distinct yellowish brown (10YR 5/8) and red (2.5YR 4/8) mottles; massive; friable; 25 percent rounded and angular cobblestones; very strongly acid; gradual wavy boundary. (0 to 15 inches thick)
2C2--64 to 76 inches; yellowish red (5YR 5/6), strong brown (7.5YR 5/6), very pale brown (10YR 8/2), and black (10YR 2/1) granitic sandy loam saprolite.
TYPE LOCATION: Madison County, Virginia; on North side of VA 613, 100 yards west of VA 230.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches. Depth to hard bedrock is more than 60 inches. Where present, depth to a lithologic discontinuity ranges from 30 to 80 inches. Rock fragments are low- to high-grade metamorphic rocks typically consisting of partially rounded and angular quartzite, granite, and other crystalline rocks up to 10 inches in diameter range from 0 to 50 percent in the A and C horizons and from 0 to 35 percent in the B horizon. The soil is very strongly or strongly acid, unless limed.
The A or Ap horizon has hue of 7.5YR through 2.5Y, value of 3 through 5, and chroma of 2 through 6. Horizons with value of 3 and chroma of 2 or 3 are less than 6 inches thick. The A horizon is sandy loam, fine sandy loam, or loam that in the fine earth fraction.
The AB or BA horizon, where present, has hue of 7.5YR or 10YR, value of 3 through 5, and chroma of 2 through 6. The AB or BA horizon is sandy loam, fine sandy loam, or loam that in the fine earth fraction.
The E horizon has hue of 7.5YR through 2.5Y, value of 3 through 5, and chroma of 2 through 6. The E horizon is sandy loam, fine sandy loam or loam in the fine earth fraction.
The BE horizon, where present, has hue of 7.5YR or 10YR, value of 4 through 6 and chroma of 3 through 6. It is sandy loam, loam, sandy clay loam, or clay loam in the fine earth fraction.
The Bt horizon has hue of 5YR or 7.5YR, value of 4 through 6, and chroma of 4 through 8. Iron depletions with chroma of 2 or less occur deeper than 24 inches of the upper boundary of the Bt horizon. Soft masses of iron accumulation in shades of yellow, brown, or red may also be present. It is loam, clay loam, or sandy clay loam in the fine earth fraction. The lower part of the Bt horizon is free of mottles in some pedons.
The BC horizon, where present, has matrix colors similar to the Bt horizon or it is streaked or mottled in shades of red, yellow, brown, and gray. It is generally coarser in texture and contains a higher content of rock fragments than the Bt horizon. It is sandy loam, loam, or sandy clay loam in the fine earth fraction.
The C horizon commonly is streaked or mottled with hue of 2.5YR throuth 10YR, value of 2 through 8 and chroma of 1 through 7. It ranges from sandy loam to clay in the fine earth fraction.
The 2C horizon, where present, has matrix colors and textures similar to the C horizon.
COMPETING SERIES: Soils in the same family include the Chilmark, Hassler, Roselle, and Tulip series. The Birdsboro and Brumbaugh series are in closely related families. Chilmark soils formed in a loamy or sandy aeolian mantle over coastal plain sediments on the islands of Nantucket and Martha's Vineyard in MLRA 149B. Hassler soils are deep to granite bedrock and formed in colluvium and residuum on mountain ridges in the Ozark Highland area (MLRA 116A). Roselle soils formed in colluvium and residuum from granite on terraces and footslopes in mountain basins in the Ozark Highland area (MLRA 116A). Tulip soils formed in colluvium from sandstone and siltstone and in residuum from underlying shale in south-central Indiana (MLRA 120). The Birdsboro soils formed in old alluvial deposits from shale, sandstone, or siltstone. The Brumbaugh soils formed in colluvium from metamorphic rocks and have a lithologic discontinuity from 30 to 60 inches.
GEOGRAPHIC SETTING: Thurmont soils are on footslopes, colluvial fans, benches, and stream terraces in the Blue Ridge mountains (MLRA 130) and Northern Piedmont (MLRA 148). Slopes range from 2 to 35 percent, but commonly are 2 to 15 percent. The soils developed in colluvium and alluvium derived from a mixture of metamorphic rocks. Mean annual temperature ranges from 52 degrees to 57 degrees. Average annual precipitation ranges from about 40 to 62 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Braddock, Dillard, Eubanks, Meadowville, Statler, Tate, Trego and Unison soils. Braddock and Unison soils have a fine particle-size control section. Dillard soils have iron depletions within 24 inches of the top of the argillic horizon. Meadowville soils have a lithologic discontinuity within the control section with significant increase in sand content. Statler and Tate soils have a seasonal high water table greater than 6 feet. Trego soils have a fragipan.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid surface runoff; moderate permeability. Depth to a seasonal high water table is 3 to 6 feet.
USE AND VEGETATION: Approximately one-fourth of the acreage has been cleared and is used for cultivated crops and pasture. Crops include corn, small grain, hay, some apple and peach orchards, berries, and vegetable crops. Vegetation consists of white oak, black oak, hickory, wild cherry, beech, yellow-poplar, black gum, Virginia pine, dogwood and elm in forested areas.
DISTRIBUTION AND EXTENT: Georgia, Virginia, Maryland, North Carolina, Pennsylvania and West Virginia; also possibly in South Carolina. The series is of moderate extent with about 64,000 acres mapped.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Frederick County, Maryland (Monocacy Soil Conservation District), 1940.
REMARKS: The 10/99 revision updates classification to the 8th Edition of Keys to Soil Taxonomy. Some pedons may have a semiactive CEC activity class, but the dominant CEC activity class is active.
The 06/2008 revision clarifies rock fragment type and diagnostic features, and adds states where used.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - zone from the mineral soil surface to 13 inches (A and E horizons)
Argillic horizon - zone between 13 and 52 inches (Bt horizons)
Base saturation, at a depth 125 cm (49 inches) below the top of the argillic horizon (62 inches), is less than 35 percent.
SIR = VA0053, VA0243 (COBBLY), VA0010 (GRAVELLY)
MLRA = 130, 148
REVISED = 10/14/92 by MHC; 10/99 by MKC; 06/2008 by DHK