LOCATION MARKLAKE TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, active, acid, thermic Alfic Udarents
TYPICAL PEDON: Marklake fine sandy loam--loblolly pine plantation. (Colors are for moist soil)
Ap--0 to 6 inches; brown (10YR 4/3) fine sandy loam; common fine distinct yellowish brown (10YR 5/6) (Bt) and pale brown (10YR 6/3) spots; few fine distinct light gray (10YR 6/1) weathered shale fragments; weak medium subangular blocky structure; friable; many fine and common medium roots; common fine and medium pores; few lignite partings up to 20 mm in size; strongly acid; clear smooth boundary.
C1--6 to 17 inches; yellowish brown (10YR 5/4) sandy clay loam; common medium faint brownish yellow (10YR 6/6) spots (Bt); common medium distinct light brownish gray (10YR 6/2) weathered shale fragments; weak coarse subangular blocky structure; friable; few fine and medium roots; common fine and medium pores; few lignite partings up to 20 mm in size; very strongly acid; gradual smooth boundary.
C2--17 to 24 inches; dark grayish brown (10YR 4/2) fine sandy loam; common medium distinct brownish yellow (10YR 6/6) (Bt) and common medium faint brown (10YR 4/3) spots; massive; friable; few fine and medium roots; few fine and medium pores; common lignite partings up to 50 mm in size; strongly acid; gradual smooth boundary.
C3--24 to 40 inches; reticulately mottled yellowish brown (10YR 5/4), brown (10YR 5/3) and brownish yellow (10YR 6/6) fine sandy loam; few medium distinct reddish yellow (7.5YR 6/8) (Bt) spots; massive; friable; few fine roots; few fine pores; many lignite partings up to 75 mm in size; very strongly acid; gradual smooth boundary.
C4--40 to 60 inches; light brownish gray (10YR 6/2) sandy clay loam; common medium distinct strong brown (7.5YR 5/6) (Bt) and few fine distinct yellow (10YR 7/6) spots; common medium faint light gray (10YR 7/2) weathered shale fragments; massive; few fine pores; strongly acid.
TYPE LOCATION: Harrison County, Texas; from the intersection of U.S. Highways 59 and 80 in Marshall; 2.6 miles south on U.S. Highway 59; 10.2 miles west and south on Texas Highway 43; 0.5 mile west on Texas Farm Road 2625; 2.1 miles southwest on county road; 315 feet east along private road; 50 feet south in recently planted plantation of loblolly pine.
RANGE IN CHARACTERISTICS: Rooting depth is greater than 60 inches. Bulldozers and dragline mining operations have mixed these materials. These soils range from 15 to 100 percent by volume remnants of the native soils with some mixing of reduced unoxidized soil materials. Fragments of the argillic horizon make up at least 3 to about 50 percent of some subhorizon within the particle-size control section. Fragments of lignite or lignite partings range from none to common and are mainly less than 3 inches across. The clay content of the composite control section averages 18 to 35 percent. Textures are mixed within horizons and vary among horizons.
The A horizon has hue of 10YR value of 3 to 6 and chroma of 2 to 6; hue of 7.5YR and 5YR value of 4 or 5 and chroma of 4 or 6. Spots range from none to many in shades of brown, yellow, red, and gray. These are mainly mottles from the native soil. Some pedons have a mottled matrix of these colors. Texture of the oxidized remnants is fine sandy loam, loam, sandy clay loam or clay loam, and the texture of the unoxidized reduced material is silt loam, loam, clay loam, or silty clay loam. The clay content ranges from 12 to 35 percent. Ironstone or hardened sandstone pebbles range from 0 to 15 percent by volume. Reaction ranges from very strongly acid to strongly acid unless recently limed. Some pedons have small individual fragments with reaction of medium acid or more; however, a mixed composite sample has pH less than 5.5.
The C horizons have hue of 2.5Y value of 5 or 6 and chroma of 4; hue of 10YR value of 3 to 6 and chroma of 2 to 6; hue of 7.5YR and 5YR value of 4 or 5 and chroma of 4 to 8. Spots range from none to many in shades of brown, yellow, red, and gray. Some pedons have a mottled matrix of these colors. Texture of the oxidized remnants is fine sandy loam, loam, sandy clay loam or clay loam, and the texture of the unoxidized material is silt loam, loam, clay loam, or silty clay loam. The composite clay content ranges from 18 to 35 percent, the percent sand is more than 45 percent and percent silt is less than 30 percent. Ironstone or hardened sandstone pebbles range from 0 to 15 percent by volume. Reaction ranges from very strongly acid to strongly acid unless recently limed. A few pedons may have small individual fragments with reaction of medium acid or more, however, a mixed composite sample will be less than pH 5.5.
COMPETING SERIES: There are no competing series in the same family. Similar series are the Bigbrown, Distell, Diswood, Gibbonscreek, Grayrock, Marclay, Pirkey, and Thermo. Diswood, Marclay, and Thermo soils have more than 35 percent clay in the control sections. Bigbrown and Grayrock soils have fine-silty control sections, nonacid reaction, and mixed mineralogy from mainly reduced soil materials. Distell and Gibbonscreek have nonacid reaction families, mixed mineralogy, and are drier for longer periods of time. Pirkey soils are mostly scraper placed, have base saturation of less than 35 percent throughout the upper meter of the soil, lignite partings and unoxidized materials are nearly all excluded in the upper 4 feet.
GEOGRAPHIC SETTING: Marklake soils are on gently sloping to moderately steep slopes of reclaimed areas following lignite strip mining. They usually occur near original box cuts and where either dragline or scraper operations have mixed dominantly oxidized materials with varying amounts of reduced materials. These soils formed from loamy and clayey materials from the lower Claiborne and Wilcox groups or from fluviatile terrace deposits. Slopes range from 1 to 20 percent. The mean annual precipitation ranges from 44 to 52 inches, annual frost free rainfall is 25 to 30 inches and PE index ranges from 64 to 80. The average summer moisture deficit is about 4 inches but the normal precipitation deficiency is plus 8 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the post-mined Marclay soils and the native Bernaldo, Bowie, Cart, Cuthbert, Eastwood, Erno, Iuka, Kirvin, Latex, and Sacul soils. The Marclay soils are on similar positions. The Bernaldo, Cart, and Erno soils are associated with high terraces and the Carrizo formation. The Bowie, Cuthbert, Kirvin, and Sacul soils are associated with the Reklaw formation. The Eastwood and Latex soils are associated with the Wilcox Group. Iuka soils are on frequently flooded bottomlands.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Areas are in pastures of coastal bermudagrass, with cool-season forage crops of crimson clover, vetch, singletary peas, and ryegrass or planted to loblolly pine or hardwood.
DISTRIBUTION AND EXTENT: East Texas, in association with lignite mining. Series is of minor extent at the present, but is increasing each year with additional mining operations.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Harrison County, Texas; 1987.
REMARKS: The Marklake soils are developing in a mixture of oxidized and unoxidized materials. Mineralogy is estimated to be siliceous because of mineralogy of most native soils in the area. The series name is coined after the mine at Martin Lake in Panola County, where it was first proposed.
Diagnostic horizons and features recognized in this series are:
Ochric epipedon - from the surface to 6 inches.
Arent feature (remnants of diagnostic horizons) - Argillic horizon fragments (Bt part of C horizons) from 6 to 60 inches.
Alfic feature - The base saturation is more than 35 percent in composite samples of the particle-size control section.
Acid reaction class feature - The average pH values range from 4.5 to 5.4 in 1:1 water on composite samples in the particle-size control section.