LOCATION FOURLOG WYTentative Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Typic Cryaquolls
TYPICAL PEDON: Fourlog clay loam - grassland (Colors are for dry soil unless otherwise noted).
01--0 to 1 inches; organic material derived from rushes and sedges; neutral (pH 6.8); abrupt wavy boundary. (1 to 2 inches thick)
A11--0 to 4 inches; dark grayish brown (10YR 4/2) clay loam, very dark brown (10YR 2/2) moist; weak medium and fine granular structure; soft, very friable, slightly sticky, slightly plastic; noncalcareous; neutral (pH 6.8); clear wavy boundary. (4 to 6 inches thick)
A12--4 to 10 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure that parts to weak fine crumbs; soft, very friable, nonsticky, slightly plastic; few small faint mottles of strong chroma; few scattered quartzite pebbles; noncalcareous; neutral (pH 7.0); abrupt wavy boundary. (6 to 10 inches thick)
A13g--10 to 16 inches; gray (5Y 5/1) silt loam, very dark gray (5Y 2/1) moist; weak medium subangular blocky structure that parts to moderate medium granules; soft, very friable, nonsticky, slightly plastic; common medium distinct yellowish brown (10YR 5/6) moist mottles; 10 percent stones and gravel; many mica flakes; noncalcareous; neutral (pH 7.0); clear wavy boundary. (4 to 10 inches thick)
B2g--16 to 38 inches; gray (5Y 5/1) gravelly stony loam, dark olive gray (5Y 4/1) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky, slightly plastic; 30 percent gravel and stones; common medium distinct reddish brown (7.5YR 5/4) moist mottles; many mica flakes; noncalcareous; neutral (pH 7.0); groundwater at depth of 42 inches.
TYPE LOCATION: Albany County, Wyoming; NE1/4 sec. 20, T.16N., R.79W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 20 to 60 inches thick. Typically these soils are noncalcareous to depths of more than 60 inches and are noncalcareous to depths of at least 40 inches in all pedons. Thin organic horizons generally occur at the surface of this soil but may be absent in some pedons. The content of organic carbon in the mineral portion of the soil ranges from about .6 to 5 percent and decreases uniformly with depth. The control section is typically light loam and contains 5 to 18 percent clay, 30 to 60 percent silt, and 25 to 60 percent sand, with less than 35 percent being fine or coarser sand. Coarse fragments range from 0 to 35 percent and generally become more numerous in the lower part of the control section. Mean annual soil temperature ranges from 33 degrees to 46 degrees F. and mean summer soil temperature ranges from 40 degrees to 58 degrees F. These soils have high water tables and are moist throughout most of the control section most seasons of the year. The A horizon has hue of 5Y through 10YR, value of 4 or 5 dry or 2 or 3 moist, and chroma of neutral through 2. It has common medium distinct to many large prominent mottles in the lower part. This horizon typically has granular or crumb primary structure but has subangular blocky structure in some pedons. It is slightly acid to mildly alkaline (pH 6.1 to 7.8). The B2g horizon has hue of 5Y through 10YR, value of 5 or 6 dry or 4 or 5 moist, and chroma of neutral to 2. It contains common medium distinct to many large prominent contrasting mottles. This horizon is slightly acid to mildly alkaline (pH 6.1 to 7.8).
COMPETING SERIES: These are the Braymill and Roseberry series. Braymill soils lack a mollic epipedon, have more than 35 percent fine or coarser sand throughout the control section and contain a significant amount of pumice. Roseberry soils are strongly or very strongly acid, and have more than 35 percent fine or coarser sand, much of which is medium coarse angular granite sand throughout the control section.
GEOGRAPHIC SETTING: The Fourlog soils are on the lower ends and concave areas of alluvial fans and sideslopes. Slopes typically range from 0 to about 10 or more percent. The soil formed in thick, noncalcareous, alluvial fan materials derived from mixed crystalline rocks. At the type location the average annual precipitation is 30 inches with peak periods of precipitation occurring in the spring and early summer months. Mean annual temperature is 33 degrees F., mean summer temperature is 46 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Foxpark and Hat soils. Foxpark soils have umbric epipedons and are well drained. Hat soils have spodic horizons.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; slow permeability.
USE AND VEGETATION: These soils are used as native pastureland or for recreational areas. Native vegetation is rushes, willows, sedges, tufted hairgrass.
DISTRIBUTION AND EXTENT: Mountainous areas of Wyoming. The series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Snowy Range Research Area, Albany County, Wyoming, 1965.
OSED scanned by SSQA. Last revised by state on 10/71.
REMARKS:
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.