LOCATION BLUELEAD SD, WYTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Argiudolls
TYPICAL PEDON: Bluelead cobbly loam in a wooded pastureland. (Colors are for air-dry soil unless otherwise stated)
A--0 to 5 inches; very dark gray (10YR 3/1) cobbly loam, black (10YR 2/1) moist; moderate fine granular structure; slightly hard, very friable; many fine roots; about 20 percent rock fragments; neutral; clear wavy boundary. (4 to 8 inches thick)
Bt1--5 to 9 inches; dark grayish brown (10YR 4/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist: weak medium prismatic structure parting to moderate fine subangular blocky; hard, friable; many fine and medium roots; shiny clay films on faces of peds; about 35 percent rock fragments; neutral; clear wavy boundary.
Bt2--9 to 18 inches; brown (10YR 5/3) very cobbly clay loam, brown (10YR 4/3) moist; moderate medium prismatic structure parting to strong fine and medium subangular blocky; hard, firm; common fine and medium roots; patchy clay films on faces of peds; about 45 percent rock fragments by volume; neutral; clear wavy boundary. (The combined Bt horizons 6 to 18 inches thick)
Bk--18 to 26 inches; very pale brown (10YR 7/3) very cobbly loam, brown (10YR 5/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable; common medium roots; about 55 percent rock fragments; few fine accumulations of calcium carbonate and as coatings on rock fragments; strong effervescence; moderately alkaline; gradual wavy boundary. (6 to 10 inches thick)
BCk--26 to 60 inches; light brownish gray (10YR 6/2) extremely cobbly loam, grayish brown (10YR 5/2) moist; massive; soft, very friable; about 65 percent rock fragments; carbonates disseminated and as coatings on rock fragments; strong effervescence; moderately alkaline.
TYPE LOCATION: Pennington County, South Dakota, about one mile north of Rockerville, about 1500 feet south and 800 feet west of the northeast corner of Section 12, T. 1 S., R. 6 E.; USGS Rockerville, S. Dak. Topographic quadrangle; lat. 43 degrees 58 minutes 48 seconds N. and long. 103 degrees 20 minutes 25 seconds W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 7 to 12 inches thick. The depth to carbonates ranges from 15 to 20 inches.
The A horizon has hue of 5YR, 7.5YR, or 10YR, value of 3 to 5 dry and 2 or 3 moist, and chroma of 1 to 3. It is loam or clay loam. It has 15 to 30 percent subrounded or rounded gravel or cobble. It is slightly acid or neutral.
The Bt horizon has hue of 5YR, 7.5YR, or 10YR, value of 3 to 6 dry and 2 to 5 moist, and chroma of 2 to 6. It is loam, clay loam or sandy clay loam. It has from 35 to 60 percent rock fragments, of which 20 to 50 percent are subrounded and rounded gravel and 15 to 40 percent rounded cobbles. It is slightly acid to slightly alkaline.
The Bk horizon has hue of 7.5YR or 10YR, value of 6 or 7 dry and 5 or 6 moist, and chroma of 2 to 4. It is loam, clay loam or sandy clay loam. It has from 35 to 70 percent rock fragments, of which 20 to 50 percent are subrounded and rounded gravel and 15 to 40 percent rounded cobble. It is a calcic horizon with 15 to 30 percent calcium carbonate equivalent. It is slightly alkaline to strongly alkaline.
The BCk horizon has properties similar to the Bk horizon except that it is not part of the calcic horizon, and has 5 to 10 percent less calcium carbonate than the overlying Bk horizon.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: The Bluelead soils are on treads and risers of old stream terraces. These soils formed in loamy alluvium or colluvium weathered from slate, schist, granite, limestone, and calcareous sandstone. Slope ranges from 0 to 40 percent. The average annual precipitation is 18 to 22 inches. The mean annual air temperature is 41 to 45 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cordeston and Virkula soils. Cordeston and Virkula soils contain less coarse fragments throughout. Cordeston soils are on toeslopes and floodplains and Virkula soils are on backslopes.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Bluelead soils are utilized primarily for grazing and wildlife habitat. The native vegetation consists of big bluestem, little bluestem, blue grama, leadplant, and scattered ponderosa pine.
DISTRIBUTION AND EXTENT: Black Hills (MLRA 62) of South Dakota. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado.
SERIES PROPOSED: Lawrence County, South Dakota, 2000. The name is from Bluelead Mountain, west of the type location.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: the zone from the surface of the soil to 9 inches (A and Bt1 horizons).
Argillic horizon: 5 to 18 inches (Bt1 and Bt2 horizons).
Calcic horizon: 18 to 26 inches (Bk horizon).
Particle-size control section: 5 to 18 inches (Bt1 and Bt2 horizons).
Soil Taxonomy version: Ninth edition to the Keys to Soil Taxonomy.
Soil moisture regime is in question. Series may be reclassified to Typic or Udic Argiustolls.