LOCATION IGOR WY
Tentative Series
Rev. TAG-DMM-RJS
05/2011
IGOR SERIES
The Igor series consists of very deep, well drained soils that formed in till derived from granite and gneiss. These soils are on ground moraines and moraines. Slopes are 2 to 8 percent. Mean annual precipitation is about 430 mm, and mean annual air temperature is about 1 degree C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Pachic Argicryolls
TYPICAL PEDON: Igor gravelly loam, in rangeland (colors are for dry soil unless otherwise noted). Surface fragments include 20 percent subrounded stones and 10 percent subrounded boulders.
A1--0 to 5 cm; very dark gray (7.5YR 3/1) gravelly loam, black (7.5YR 2.5/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many fine roots; many fine interstitial pores; 15 percent gravel and 5 percent cobbles; neutral (pH 7.2); clear wavy boundary.
A2--5 to 24 cm; dark brown (7.5YR 3/2) very stony loam, very dark brown (7.5YR 2.5/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine interstitial pores; 20 percent gravel, 12 percent cobbles and 20 percent stones; slightly alkaline (pH 7.4); clear wavy boundary. (combined thickness of the A1 and A2 horizons - 15 to 30 cm)
Bt--24 to 70 cm; brown (10YR 4/3) extremely gravelly sandy clay loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine tubular pores; 3 percent faint clay films on all faces of peds; 40 percent gravel, 10 percent cobbles and 12 percent stones; slightly alkaline (pH 7.5); clear smooth boundary. (40 to 60 centimeters thick)
BC--70 to 200 cm; dark grayish brown (10YR 4/2) very gravelly sandy loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine roots; many fine tubular pores; 35 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.6).
TYPE LOCATION: Sublette County, Wyoming: located approximately 2550 feet North and 115 feet East of the southwest corner of section 19, T. 32N, R. 106W; USGS Fremont Butte, Wyoming topographic quadrangle; 42 degrees 43 minutes 40.00 seconds north latitude and 109 degrees 32 minutes 19.00 seconds west longitude.
RANGE IN CHARACTERISTICS:
Soil temperature - 1.5 to 3.5 degrees C.
Mollic epipedon thickness - greater than 50 cm
Depth to argillic horizon 15 to 30 cm
A1 horizon
Hue: 10YR or 7.5YR; dry or moist
Value: 3 or 4 dry; 2.5 or 3 moist
Chroma: 1 or 2; dry or moist
Clay content: 9 to 18 percent
Rock Fragments: 15 to 30 percent--10 to 25 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction: pH 6.8 to 7.4
A2 horizon
Hue: 10YR or 7.5YR; dry or moist
Value: 3 or 4 dry; 2.5 or 3 moist
Chroma: 1 or 2; dry or moist
Clay content: 9 to 18 percent
Rock Fragments: 35 to 60 percent--15 to 30 percent gravel, 5 to 15 percent cobbles, 10 to 25 percent stones
Reaction: pH 6.8 to 7.4
Bt horizon
Hue: 10YR or 7.5YR; dry or moist
Value: 3 or 4; dry or moist
Texture: sandy loam, sandy clay loam
Clay content: 18 to 27 percent
Rock Fragments: 40 to 75 percent--30 to 50 percent gravel, 5 to 15 percent cobbles, 5 to 15 percent stones
Reaction: pH 7.2 to 7.6
BC horizon
Hue: 10YR or 7.5YR; dry or moist
Value: 4 or 5; dry or moist
Chroma: 2 or 3; dry or moist
Clay content: 6 to 15 percent
Rock Fragments: 40 to 60 percent--35 to 50 percent gravel, 5 to 15 percent cobbles, 0 to 10 percent stones
Reaction: pH 7.2 to 7.6
COMPETING SERIES:
Angelwhine (CA) - have a xeric moisture regime
Aspetill (CA) - have a xeric moisture regime
Badwater (WY) - have greater than 35 percent boulders in the argillic horizons
Bickmore (UT) - are moderately deep to a lithic contact
Blackbear (MT) - are moderately deep to a lithic contact
Bluebell (NV) - are moderately deep to a lithic contact
Booneville (ID) - have an udic moisture regime
Buena Vista (CO) - are moderately deep to a lithic contact
Dab (NV) - have a xeric moisture regime
Dailybasin (MT) - have greater than 15 percent clay in the BC horizon
Delhew (NV) - have a xeric moisture regime
Hawkinspeak (CA) - are moderately deep to a lithic contact
Keman (ID) - have a xeric moisture regime
Littlemud (NV) - are moderately deep to a lithic contact
Lostcannon (CA) - have a xeric moisture regime
Monibasin (CA) - have a xeric moisture regime
Panin (NV) - are moderately deep to a lithic contact
Parkalley (ID) - have a xeric moisture regime
Parkay (UT) - have a xeric moisture regime
Rangertaft (NV) - are moderately deep to a lithic contact
Redbird (SD) - have secondary calcium carbonate accumulation
Rutherford (ID) - are moderately deep to a lithic contact
Sweetmount (CA) - are deep to a paralithic contact
Woodhurst (MT) - are moderately deep to a lithic contact
GEOGRAPHIC SETTING:
Landform - ground moraines, moraines
Elevation - 2270 to 2290 meters
Slope - 2 to 8 percent
Parent Material - till derived from granite and gneiss.
Climate - long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation - 380 to 485 mm with peak periods of precipitation occurring during the spring
Mean annual air temperature - 0.5 to 1.5 degrees C.
Frost-free period - 25 to 45 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Igor soils are primarily used for rangeland. The potential native vegetation is mainly mountain big sagebrush, Idaho fescue, spike fescue, bluebunch wheatgrass, and antelope bitterbrush.
DISTRIBUTION AND EXTENT: Igor soils are of small extent in southwestern Wyoming. MLRA - 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Sublette County, Wyoming, 2011. The series name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 70 cm (A1, A2, Bt horizons)
Argillic horizon - from 24 to 70 cm (Bt horizon)
Particle-size control section - from 24 to 70 cm (Bt horizon).
Igor soils have a cryic temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.