LOCATION COGGINSFLAT ORTentative Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Vitrandic Durixerolls
TYPICAL PEDON: Cogginsflat ashy sandy loam, on a 4 percent slope, rangeland. (Colors are for moist soils unless otherwise noted.)
A--0 to 11 inches; very dark grayish brown (10YR 3/2) ashy sandy loam, grayish brown (10YR 5/2) dry; moderate very thick platy structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine roots; many fine dendritic tubular pores; 5 percent gravel; neutral (pH 7.0); clear wavy boundary. (7 to 15 inches thick)
2Bt--11 to 18 inches; dark brown (10YR 3/3) sandy clay loam, brown (10YR 5/3) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common very fine and fine and few medium roots; many fine and very fine dendritic tubular pores; few distinct clay films on faces of peds and lining pores; 10 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary. (5 to 15 inches thick)
2Bq--18 to 25 inches; brown (7.5YR 4/2) sandy loam, brown (7.5YR 5/2) dry; moderate fine and medium subangular blocky structure; weakly cemented, hard, very firm, slightly sticky and non plastic; few fine roots and few medium roots; few fine tubular pores; 10 percent gravel; slightly alkaline (pH 7.6); clear wavy boundary. (0 to 10 inches thick)
2Bkqm--25 to 50 inches; brown (7.5YR 4/3) gravelly sandy loam, brown (7.5YR 5/3) dry; strongly cemented duripan; common carbonate masses in cracks, violently effervescent; 20 percent gravel; slightly alkaline (pH 7.8); clear wavy boundary. (5 to 30 inches thick)
3Cr--50 to 60 inches; partially consolidated volcanic tuff, continuous and coherent but can be dug with a spade.
TYPE LOCATION: Crook County, Oregon; about 5 miles northeast of the town of Paulina, Oregon, located about 1075 feet east and 2380 feet south of the northwest corner of section 29. T. 16S. R. 10E. (Latitude 44 degrees 9 minutes 27.9 seconds N., Longitude 119 degrees 52 minutes 39.7 seconds W. NAD83) Paulina, Oregon USGS quadrangle; UTM 269873 meters E, 4893415 meters N, Zone 11 NAD 83.
RANGE IN CHARACTERISTICS: These soils are usually moist but are dry in the moisture control section for 70 to 90 days following the summer solstice. The mean annual soil temperature is 42 to 47 degrees F. Depth to the 2Bt horizon is 7 to 20 inches. Depth to duripan is 20 to 40 inches. The mollic epipedon is 10 to 30 inches thick. The particle-size control section averages 18 to 30 percent clay.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is ashy sandy loam or ashy loam. It contains 0 to 10 percent gravel.
The 2Bt horizon has value of 2 or 3 moist, 3 through 5 dry, and chroma of 2 or 3 moist and dry. It is ashy sandy clay loam, sandy clay loam, ashy clay loam, or clay loam and contains 5 to 20 percent gravel and 18 to 40 percent clay.
The 2Bq horizon if present has a hue of 7.5YR or 10YR and a value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 through 4 moist and dry. It is sandy loam or loam and contains 5 to 35 percent gravel and 10 to 25 percent clay.
The duripan is very weakly to strongly cemented (haplic subgroup) gravels and sand to a depth of 40 inches or more. The duripan overlies paralithic sedimentary strata.
COMPETING SERIES: This is the Wolfbutte series. Wolfbutte soils contain pumice paragravels, are non-effervescent in the duripan, and lack paralithic tuff below the duripan.
GEOGRAPHIC SETTING: Cogginsflat soils are on low hills at elevations of 3,500 to 4,500 feet. Slopes range from 2 to 30 percent. The soils formed in residuum and colluvium derived from tuff with an influence of volcanic ash in the surface. The climate is characterized by cold wet winters and hot dry summers. The mean annual precipitation is 12 to 14 inches, the mean annual temperature is 40 to 46 degrees F, and the frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fopiano, Choptie, Roschene, Powellbutte, and Booth soils. Fopiano soils are clayey and 10 to 20 inches to paralithic contact. They are found in complex with Mascall soils on low hills. Choptie soils are on adjacent hillslopes. They are 12 to 20 inches deep to a lithic contact. Roschene soils are on adjacent stream terraces. They are over 60 inches deep and are moderately well drained. Powellbutte and Booth soils are on adjacent plateaus. Powellbutte soils are 20 to 40 inches to lithic contact and are vitrandic. Booth soils are 20 to 40 inches to lithic contact with over 35 percent clay in the particle size control section.
DRAINAGE AND PERMEABILITY: Well drained, permeability is moderate above the duripan.
USE AND VEGETATION: Cogginsflat soils are used for rangeland, irrigated and non-irrigated pastureland and hayland. The native vegetation is mountain big sagebrush, Idaho fescue, bluebunch wheatgrass, and Thurber's needlegrass.
DISTRIBUTION AND EXTENT: East-Central Oregon; MLRA 10. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Crook County Area, Oregon; 2007.
REMARKS: Diagnostic horizons and features in this pedon include:
Mollic epipedon - the zone from the surface to a depth of 18 inches (A, 2Bt horizons)
Vitrandic feature - from the surface to a depth of 11 inches (A horizon)
Argillic horizon - from a depth of 11 to 18 inches (2Bt horizon)
Duripan feature from a depth of 25 to 50 inches (2Bkqm horizon)
In 2008 the tentative series name was changed from Mascall to Cogginsflat to order to reduce confusion with the geologic Mascall Formation name.