LOCATION TORCHLIGHT WY+MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, mesic Vertic Torriorthents
TYPICAL PEDON: Torchlight silty clay loam - grassland (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; light brownish gray (2.5Y 6/2) heavy silty clay loam, dark grayish brown (2.5Y 4/2) moist; moderate and strong, very fine granular structure; soft, very friable; calcareous; strongly alkaline (pH 9.0); abrupt smooth boundary. (3 to 6 inches thick)
Clca--4 to 8 inches; Grayish brown (2.5Y 5/2) heavy silty clay loam, dark grayish brown (2.5Y 4/2) moist; moderate and strong fine angular blocky structure; very hard, very friable; weak to moderate secondary calcium sulfate and calcium carbonate accumulation occurring as crystals and small concretions; calcareous; strongly alkaline (pH 9.0); gradual smooth boundary. (3 to 6 inches thick)
C2cs--8 to 60 inches; light brownish gray (2.5Y 6/2 dry) heavy silty clay loam, dark grayish brown (2.5Y 4/2 moist); massive; hard, very friable; visible secondary calcium sulfate and calcium carbonate occurring as crystals, as small concretions, and in thin seams and streaks; calcareous; strongly alkaline (pH 9.0). (Several feet thick)
TYPE LOCATION: Bighorn County, Wyoming; approximately 276 feet north and 252 feet east of the junction of the Basin-Gardner road and the old airport access road, in the SW quarter of the SE quarter of sec. 10, T.51N., R.93W.
RANGE IN CHARACTERISTICS: These soils are calcareous throughout. The organic carbon content of the A horizon ranges from .5 to 1 percent and organic carbon decreases uniformly with depth. Conductivity of the control section ranges from approximately 2 to 8 millimho and exchangeable sodium ranges from 15 to 25 percent throughout most of the control section. Cation exchange capacity ranges from approximately 60 to 90 millequivalents per 100 grams of clay. The control section is typically heavy silty clay loam or light silty clay with clay ranging from 35 to 50 percent, silt from 20 to 50 percent, and sand from 10 to 40 percent with typically less than 15 percent fine sand or coarser. Content of coarse fragments ranges from 0 to 15 percent but is typically less than 3 percent and consists mostly of shale chips. The A horizon has hue of 5YR through 10YR, chroma of 1 through 3 and value of 6 or 7 dry and 4 or 5 moist. It is soft to slightly hard. This horizon is strongly to very strongly alkaline (pH 8.8 to 10) and contains 15 to 25 percent exchangeable sodium. The Ccs horizon has hue of 5Y through 10YR. It is strongly to very strongly alkaline (pH 8.8 to 10) and has approximately 2 to 10 percent CaC03 equivalent spread rather uniformly throughout the control section and not concentrated in any particular horizon. This horizon contains 15 to 25 percent exchangeable sodium. Calcium sulfate accumulation is moderate throughout the control section but is not concentrated in one horizon sufficiently to constitute a gypsic horizon.
COMPETING SERIES: These are the McCollough, Nowood and Ragtown series. McCollough soils have a paralithic contact at depths of 20 to 40 inches. Nowood and Ragtown soils have less than 15 percent exchangeable sodium.
GEOGRAPHIC SETTING: The Torchlight soils are on gently to moderately sloping alluvial fans and valley filling sideslopes below exposures of olive and gray highly gypsiferous and very alkaline shale. Slope gradients typically range from 0 to 10 percent. The soils formed in highly alkaline saline and gypsiferous parent sediments derived as alluvial fan sediments from sedimentary rock. At the type location the average annual precipitation is about 8 inches, approximately 6 inches of which falls during the months of April through September. The mean annual soil temperature is 48 degrees F. and the mean summer soil temperature is 68 degrees F.
PRINCIPALLY ASSOCIATED SOILS: These are the competing Nowood and McCollough soils and the Chipeta and Persayo soils. Chipeta and Persayo soils have a paralithic contact at depths of less than 20 inches.
DRAINAGE AND PERMEABILITY: Well-drained; rapid runoff; slow permeability.
USE AND VEGETATION: These soils are used principally as native pastureland. Principal native plants are weeds, saltbush, and scattered grasses.
DISTRIBUTION AND EXTENT: Basin areas of central and northern Wyoming. The series is moderately extensive .
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Carbon County (Bridger Area) Montana, 1971.
OSED scanned by NSSQA. Last revised by state on 9/71.