LOCATION THORNCREEK IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Chromic Haploxererts
TYPICAL PEDON: Thorncreek extremely cobbly silty clay loam - rangeland at an elevation of 4,000 feet. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; dark grayish brown (10YR 4/2) extremely cobbly silty clay loam, dark brown (10YR 3/3) moist; weak fine and medium subangular block structure parting to weak fine granular; slightly hard, very friable, very sticky and very plastic; common very fine and fine and few medium and coarse roots; common fine and very fine tubular and few very fine and fine irregular pores; 5 percent gravel, 60 percent cobbles, 15 percent stones; common 1.0 cm wide cracks; neutral (pH 6.6); clear smooth boundary. (2 to 7 inches thick)
A2--3 to 8 inches; dark brown (7.5YR 4/2) silty clay loam, dark brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, very sticky and very plastic; common very fine and fine and few medium and coarse roots; common fine and very fine tubular and few fine and very fine irregular pores; few patchy distinct pressure faces on faces of peds; few 1.0 cm wide cracks; neutral (pH 6.8); abrupt smooth boundary. (0 to 12 inches thick)
Bss1--8 to 17 inches; dark brown (7.5YR 4/2) silty clay, dark brown (10YR 4/3) moist; strong coarse prismatic structure; hard, firm, very sticky and very plastic; few fine and very fine roots; few very fine and fine tubular and irregular pores; few intersecting slickensides and patchy distinct pressure faces; few 1.0 cm wide cracks; neutral (pH 7.0); clear smooth boundary. (8 to 35 inches thick)
Bss2--17 to 29 inches; dark brown (7.5YR 4/2) silty clay, dark yellowish brown (10YR 4/4) moist; strong coarse prismatic structure; very hard, very firm, very sticky and very plastic; few very fine roots; few very fine and fine tubular and irregular pores; common intersecting slickensides and pressure faces; few 1.0 cm wide cracks; 10 percent cobbles; neutral (pH 7.1); clear wavy boundary. (0 to 16 inches thick)
Bss3--29 to 37 inches; light brown (7.5YR 6/4) silty clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots on faces of peds; common very fine and fine tubular pores; common intersecting slickensides and pressure faces; few 1.0 cm wide cracks; very slightly effervescent in spots; mildly alkaline (pH 7.4); gradual wavy boundary. (0 to 10 inches thick)
Bq--37 to 41 inches; pink (7.5YR 7/4) very cobbly loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure parting to moderate fine granular; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine and fine tubular pores; 10 percent gravel, 20 percent cobbles, and 10 percent stones; 1 to 2 mm thick silica coats on undersides of rock fragments; mildly alkaline (pH 7.4); abrupt broken boundary. (0 to 8 inches thick)
2R--41 inches; slightly weathered basaltic bedrock with weathered discontinuous silica coating filling some fractures and cementing some of the more stable bedrock.
TYPE LOCATION: Gooding County, Idaho; about 10 miles north and 3 miles west of Bliss, about 1,900 feet north and 200 feet east of the southwest corner of Sec. 15, T4S, R12E. Latitude - 43 degrees north, 4 minutes, 24 seconds; Long. - 115 degrees west, 1 minute, 55 seconds.
RANGE IN CHARACTERISTICS:
Soil temperature - 50 to 53 degrees F.
Depth to bedrock - 40 to 60 inches
Clay (control section average) - 35 to 52 percent
Reaction - neutral to mildly alkaline
Cracks - open July through October; closed during winter and early spring; 1 to 3 cm wide at a depth of 50 to 100 cm and extending upwards to the surface
Present in some pedons - Bkq, Bk, Bsskq, Bssq horizons
A1 horizon
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 2 to 4 dry or moist
Rock fragments - 5 to 10 percent gravel
- 45 to 60 percent cobbles
- 5 to 15 percent stones
A2 horizon
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 2 to 4 dry or moist
Rock fragments - 0 to 10 percent gravel
- 0 to 5 percent cobbles
- 0 to 5 percent stones
Bss horizons
Hue - 10YR or 7.5YR
Value - 4 through 7 dry, 3 through 6 moist
Chroma - 2 through 6 dry or moist
Texture - SIC, SICL
Clay content - 30 to 60 percent
Calcium carbonate content - 0 to 5 percent
Rock fragments - 0 to 15 percent gravel
- 0 to 10 percent cobbles Intersecting
slickensides - few to common
Bq horizon
Hue - 10YR or 7.5YR
Value - 6 through 8 dry, 4 through 6 moist
Chroma - 4 or 5 dry or moist
Texture - CBV-L, CBV-CL, CL, L
Clay content - 25 to 35 percent
Calcium carbonate content - 0 to 5 percent
Rock fragments - 5 to 15 percent gravel
- 0 to 25 percent cobbles
- 0 to 10 percent stones and boulders
COMPETING SERIES: This is the McHandy series. McHandy soils have a duripan at 40 to 60 inches.
GEOGRAPHIC SETTING: Thorncreek soils are on basalt plateaus and mesas. Thorncreek soils are underlain by basalt and formed in loess. Slopes are 1 to 6 percent. Elevations range from 3,600 to 4,400 feet. The average annual precipitation is 9 to 11 inches. The average annual air temperature is 48 to 51 degrees F. and the frost free period is 100 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mchandy soils on slightly convex interfluves. Mchandy soils have intersecting slickensides.
DRAINAGE AND PERMEABILITY: Well drained; runoff is rapid; permeability is very slow.
USE AND VEGETATION: Thorncreek soils are used for rangeland. Potential native vegetation is low sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Thorncreek soils are of small extent in south central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gooding County, Idaho, 1993.
REMARKS: This revision changes the classification from Xerertic Camborthids to Chromic Haploxererts.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: the zone from 0 to 17 inches (A1, A2 and B1 horizons)
Cambic horizon: the zone from 8 to 37 inches (Bss1, Bss2, and Bss3 horizons)
The particle-size control section: the zone from 10 inches to 40 inches