LOCATION IRONBUTTE WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal over fragmental, mixed, superactive, nonacid, mesic Aridic Ustorthents
TYPICAL PEDON: Ironbutte channery loam - on a 15 percent southwest facing slope utilized as range land. (Colors are for dry soils unless otherwise stated)
A--0 to 4 inches; light reddish brown (5YR 6/3) channery loam, reddish brown (5YR 4/3) moist; moderate very fine granular structure; soft, very friable; 20 percent channers; slightly alkaline (pH 7.4); clear smooth boundary. (3 to 6 inches thick)
C--4 to 12 inches; light reddish brown (5YR 6/4) very channery loam, reddish brown (5YR 4/4) moist; massive; soft, very friable; 55 percent channers 1/2 to 5 inches in length; slightly alkaline (pH 7.4); clear wavy boundary. (4 to 17 inches thick)
2C--12 to 60 inches; fractured porcelanite. Intricacies between coarse fragments are void of fines.
TYPE LOCATION: Campbell County, Wyoming; about 660 feet north and 250 feet west of the southeast corner of Sec. 19, T 50 N, R 71 W.; USGS Gillette East, WY topographic quadrangle; lat. 44 degrees 17 minutes 33 seconds N. and long. 105 degrees 25 minutes 47 seconds W.
RANGE IN CHARACTERISTICS: Depth to the fragmental material ranges from 7 to 20 inches. These soils are typically noncalcareous throughout the loamy-skeletal part of the control section but some pedons have carbonates within 6 inches. The fragmental materials in some pedons are inconsistently calcareous. The weighted average organic carbon content of the material above the fragmental beds ranges from approximately 0.4 to 1.0 percent. Conductivity is typically less than 2 mmhos/cm and exchangeable sodium percentage is normally less than 3 percent. The mean annual soil temperature ranges from 47 to 53 degrees F. The soil temperature at 20 inches is 41 degrees F. or higher for 175 to 210 days. The fragmental material contains interstices ranging from 2 mm to over 2 cm in diameter. These are devoid of any fine earth material.
The A horizon has hue of 5YR, 7.5YR or 10YR, value of 5 to 7, 3 to 6 moist, and chroma of 2 to 6. When the A horizon has a value of 5 dry and 3 moist, it is too thin or contains too little organic matter to be a mollic epipedon. Texture is channery loam, very channery loam, loam, channery fine sandy loam, very channery fine sandy loam or fine sandy loam. Rock fragments range from 5 to 40 percent, with 0 to 5 percent flagstone. Reaction is neutral or slightly alkaline. Some pedons have an AC horizon.
The C horizon has hue of 2.5YR, 5YR, 7.5YR or 10YR, value of 4 to 7, 3 to 6 moist, and chroma of 2 to 8. Where the horizon has color value of 5 or less dry and 3 moist the organic matter is too low to be mollic. The high chromas in the horizon are related to colors inherent to the parent material and are not related to soil development characteristic of a cambic horizon. Texture is very channery loam, extremely channery loam, very channery fine sandy loam or extremely channery fine sandy loam. Rock fragments range from 35 to 90 percent, with 0 to 15 percent flagstones and 0 to 5 percent stones. Reaction is neutral to slightly alkaline. Moderately alkaline reactions may occur where the horizon is derived from sodic porcelanite.
The 2C horizon consists of fractured and/or collapsed porcelanite beds. A fine-earth matrix is uncommon, but when present is less than 5 percent. Colors of the rock are quite variable but commonly have 10R or 2.5YR hue. Hues of 5YR have been recorded in some areas.
COMPETING SERIES: This is the Muleherder series. Muleherder soils are moderately deep to fragmental, porcelanite beds.
GEOGRAPHIC SETTING: The Ironbutte series occurs on hills, knolls and the crests and shoulders of ridges. Slopes range from 0 to 75 percent. The soil is developing in thin mantels of medium to moderately fine textured, noncalcareous, channery materials weathered principally from porcelanite beds. The average annual precipitation ranges from 15 to 17 inches with peak periods of precipitation occurring in April, May, and June. The mean annual air temperature ranges from 44 to 50 degrees F., and the mean summer temperature is 65 degrees F. Elevation is 3,500 to 5,800 feet. The frost-free season is 105 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deekay, Fairburn, Mittenbutte (T), Muleherder (T) and Ucross soils. The Deekay soils have argillic horizons and lack fragmental discontinuities. Fairburn, Mittenbutte and Ucross soils lack fragmental discontinuities. Muleherder soils are moderately deep to fractured porcelanite. Deekay occur on flats and footslopes. Fairburn, Mittenbutte, Muleherder and Ucross soils occur on similar positions as Ironbutte soils.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; runoff is negligible to high depending on slope; permeability is moderate over very rapid.
USE AND VEGETATION: They are used as native rangeland. Native vegetation includes sage, prairie junegrass, Sandberg bluegrass, and needleandthread. Some pedons have ponderosa pine and juniper.
DISTRIBUTION AND EXTENT: Northeastern Wyoming and possibly adjacent areas of Montana and South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado.
SERIES ESTABLISHED: Campbell County, Southern Part, Wyoming; 2001.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 3 inches (A horizon)
Fragmental discontinuity - 16 inches (top of 2C horizon)