LOCATION FINSEL ORTentative Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Vitrandic Argixerolls
TYPICAL PEDON: Finsel ashy silt loam - rangeland, on a 26 percent, northeast-facing slope at elevation of 4,820 feet. (When described on September 19, 2001, the soil was slightly moist in the surface 5 inches, but was dry below. Colors are for moist soil unless otherwise stated.)
A1--0 to 3 inches; black (10YR 2/1) ashy silt loam, dark gray (10YR 4/1) dry; moderate very fine granular structure; soft, very friable, nonsticky and nonplastic; few fine and common very fine roots; few fine and many very fine irregular pores; 5 percent gravel; neutral (pH 6.6); gradual smooth boundary.
A2--3 to 10 inches; very dark brown (10YR 2/2) ashy silt loam, dark grayish brown (10YR 4/2) dry; moderate medium and coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine and common very fine roots; few fine and common very fine tubular pores; 5 percent gravel; neutral (pH 6.6); gradual smooth boundary. (Combined thickness of the A horizon is 7 to 14 inches.)
2BAt--10 to 16 inches; very dark grayish brown (10YR 3/2) gravelly clay loam, dark grayish brown (10YR 4/2) dry; moderate medium and coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine roots; common very fine tubular pores; few faint clay films on ped faces; 5 percent cobbles and 20 percent gravel; neutral (pH 6.7); clear wavy boundary. (3 to 8 inches thick)
2Bt--16 to 30 inches; dark brown (7.5YR 3/2) very cobbly clay, brown (7.5YR 4/2) dry; strong fine and medium subangular blocky structure; hard, firm, moderately sticky and very plastic; few very fine tubular pores; many distinct clay films on ped faces and in pores; 25 percent cobbles and 25 percent gravel; neutral (pH 6.8); clear wavy boundary. (9 to 16 inches thick)
2BC--30 to 34 inches; very dark brown (7.5YR 2.5/2) gravelly clay loam, dark brown (7.5YR 3/2) dry; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine tubular pores; 20 percent gravel; neutral (pH 6.6); abrupt wavy boundary. (0 to 10 inches thick)
3Cr--34 to 37 inches; moderately cemented tuff that can be cut with a spade. (0 to 5 inches thick)
3R--37 inches; indurated tuff.
TYPE LOCATION: Grant County, Oregon; located along upper Branson Creek about 8 miles northwest of the junction of Highways 19 and 26; 10 feet north and 2,300 feet west of the southeast corner of section 3, T. 11 S., R. 26 E. (Latitude 44 degrees, 38 minutes, and 2.08 seconds N. and Longitude 119 degrees, 34 minutes, and 33.81 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 44 to 47 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 75 to 90 consecutive days following the summer solstice. Thickness of the mollic epipedon is 20 to 40 inches and includes part or all of the argillic horizon. The upper 7 to 14 inches has an estimated bulk density of 1.10 to 1.30 g/cc, volcanic glass content of 5 to 25 percent, acid oxalate extractable aluminum plus one-half acid oxalate extractable iron of 0.4 to 0.7 percent, and 15 bar water retention of 5 to 20 percent for air dried samples. The particle-size control section average 35 to 45 percent clay and 35 to 60 percent coarse fragments by volume. Organic matter is estimated to range from 3 to 5 percent in the A horizon. Solum thickness and depth to lithic contact with basalt or tuff ranges from 20 to 40 inches.
The A horizon has value of 2 or 3 moist, 4 or 4 dry, and chroma of 1 through 3 moist or dry. It is ashy silt loam or ashy loam with 15 to 27 percent clay. It has 0 to 3 percent stones, 0 to 3 percent cobbles, and 5 to 20 percent gravel. In some pedons, the amount of sandsized pumice varies from 5 to 15 percent.
The 2BAt horizon has value of 4 or 5 dry, and chroma of 1 or 2 moist or dry. It is clay loam with 27 to 40 percent clay. It has 5 to 30 percent cobbles and 10 to 30 percent gravel.
The 2Bt horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 2 to 4 moist, 3 through 6 dry. It is clay loam or clay with 35 to 50 percent clay. It has 20 to 60 percent cobbles and 15 to 40 percent gravel. It is neutral or slightly alkaline.
The 2BC horizon, when present, has hue of 10YR or 7.5YR, value of 2.5 or 3 moist, 3 or 4 dry, and chroma of 2 to 4 moist and dry. It is loam or clay loam with 25 to 35 percent clay. It has 0 to 10 percent cobbles and 15 to 25 percent gravel.
COMPETING SERIES: These are Breeseranch, Dupratt, Erakatak, and Menbo series. Breeseranch soils have an 0 horizon, are deep to bedrock, and the mollic epipedon is less than 20 inches thick. Dupratt soils have an O horizon and 50 to 60 percent clay. Erakatak soils have a mollic epipedon less than 20 inches thick. Menbo soils have an oxalate extractable Al + Fe less than 0.4 in the surface horizons.
GEOGRAPHIC SETTING: Finsel soils are on north-facing hillslopes and have slopes of 12 to 70 percent. These soils formed in colluvium and residuum from basalt and tuff mixed with loess and volcanic ash in the surface. Elevations are 3,400 to 5,400 feet. These soils can be characterized by cold, wet winters and hot, dry summers. Mean annual precipitation is 12 to 18 inches. Mean January temperature is about 24 degrees F. and mean July temperature is about 67 degrees F. Mean annual temperature is 41 to 45 degrees F. The frost-free period is 30 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Camool, Hutchley, Kishwalk, and Waterbury soils. Camool soils are north-facing hillslopes with Finsel soils and are 12 to 20 inches to a lithic contact. Hutchley soils are shallow, loamy-skeletal, and are found on east facing slopes of north-south trending canyons. Kishwalk and Waterbury soils mesic and are found on south facing slopes. Kishwalk soils moderately deep to bedrock whereas Waterbury soils are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained, rapid to very rapid runoff; slow permeability.
USE AND VEGETATION: Livestock grazing and wildlife habitat. Native vegetation is Idaho fescue, bluebunch wheatgrass, Sandberg bluegrass and threetip sagebrush.
DISTRIBUTION AND EXTENT: East central Oregon. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Grant County, Oregon. Name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - 0 to 34 inches (A1, A2, 2BAt, 2Bt, and 2BC horizons)
Argillic horizon - 10 to 30 inches (BAt and 2Bt horizons)
Paralithic contact - at 34 inches (Cr horizon)
Lithic contact - at 37 inches (R horizon)
PSCS - 10 to 30 inches (2BAt and 2Bt horizons)
Vitrandic feature - 0 to 10 inches (A1 and A2 horizons)
Xeric moisture regime
ADDITIONAL DATA: Partial lab data is available for this soil. Lab sample S03OR-023-001 was taken from Grant County and sent to NSSL, Lincoln, NE (sampled on 12/2002)