LOCATION MINKWELL OREstablished Series
TAXONOMIC CLASS: Ashy over medial, amorphic over mixed Alfic Vitricryands
TYPICAL PEDON: Minkwell ashy sandy loam - woodland, on a 25 percent southeast facing slope at 3200 feet elevation. (When described (8-20-84), the soil was moist below 3 inches. Colors are for moist soils unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed litter of Douglas fir, white fir, ponderosa pine and incense cedar needles and twigs.
A1--1 to 3 inches; dark brown (7.5YR 3/4) ashy sandy loam, brown (10YR 4/3) dry; moderate fine granular structure; slightly hard, friable, nonsticky and nonplastic; common very fine, fine and coarse and many medium roots; many very fine and fine interstitial pores; 5 percent subangular gravel, 2-5 millimeters; neutral (pH 7.0); clear smooth boundary.
A2--3 to 11 inches; dark brown (7.5YR 3/4) ashy sandy loam, dark yellowish brown (10YR 4/4) dry; weak fine granular structure; slightly hard, friable, nonsticky and nonplastic; common very fine, fine and coarse and many medium roots; many very fine and fine interstitial pores; 5 percent subangular gravel, 2-5 millimeters; neutral (pH 7.0); gradual wavy boundary. (Combined thickness of the A horizon is 8 to 16 inches)
Bw--11 to 24 inches; dark brown (7.5YR 3/4) ashy sandy loam, brown (7.5YR 4/4) dry; weak fine subangular blocky structure parting to single grain; slightly hard, friable, nonsticky and nonplastic; common fine and medium and few coarse roots; common very fine and fine interstitial pores; 5 percent subangular gravel, 2-5 millimeters; 5 percent dark brown weakly cemented nodules; neutral (pH 7.0); clear irregular boundary. (12 to 15 inches thick)
2Bwb--24 to 35 inches; dark reddish brown (5YR 3/4) cobbly medial loam, brown (7.5YR 4/4) dry; moderate medium and coarse subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; common fine and medium and few coarse roots; common fine interstitial and vesicular and few fine tubular pores; 5 percent subangular gravel and 15 percent subangular cobbles; neutral (pH 7.2); gradual wavy boundary. (6 to 13 inches thick)
3Btb1--35 to 48 inches; dark reddish brown (5YR 3/4) cobbly medial clay loam, brown (7.5YR 4/4) dry; moderate medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and medium and few coarse roots; common fine interstitial and vesicular and few fine tubular pores; common distinct clay films on peds and in pores; 5 percent subangular gravel and 15 percent subangular cobbles; neutral (pH 7.2); gradual wavy boundary. (10 to 18 inches thick)
3Btb2--48 to 61 inches; dark brown (7.5YR 3/4) cobbly medial clay loam, brown (7.5YR 4/4) dry; moderate medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few fine, medium, and coarse roots; common fine interstitial and vesicular and few fine tubular pores; many distinct clay films on peds and in pores; 5 percent gravel; 10 percent cobbles; neutral (pH 7.2).
TYPE LOCATION: Jefferson County, Oregon; on USFS road 1280-220, 0.5 mile from the junction with USFS road 1280-200; northeast quarter of section 8, T. 12 S., R. 9 E. (Latitude 44 degrees, 31 minutes, 00 seconds N, Longitude 121 degrees, 40 minutes, 00 seconds W)
RANGE IN CHARACTERISTICS: The depth of the soil to cobbly glacial till material is 20 to 30 inches. Depth to the buried argillic horizon (3Btb horizon) is 30 to 40 inches. Depth to bedrock is greater than 60 inches. The 20 to 30 inch thick ash mantle contains 70 to 90 percent glass and glass-coated aggregate, phosphate retention of 70 to 90 percent, acid oxalate aluminum plus one-half the acid oxalate iron of 1.0 to 2.0 percent, and 15-bar water content of 10 to 15 percent on dried samples and 15 to 20 percent on undried samples. The glacial till material contains 30 to 50 percent glass and glass-coated aggregate, phosphate retention of 45 to 70 percent, acid oxalate aluminum plus one-half the acid oxalate iron of 0.4 to 1.0 percent, and 15-bar water content of 15 to 25 percent on dried samples and 25 to 35 percent on undried samples. The soil moisture control section is usually moist but is dry in all parts for 30 to 45 consecutive days after the summer solstice. The mean annual soil temperature is 40 to 45 degrees F. The mean summer soil temperature 43 to 47 degrees F. The soil is neutral throughout.
The Oi horizon is 1 to 3 inches thick except where disturbed.
The A horizon has a hue of 7.5YR moist, 7.5YR or 10YR dry with value of 2 or 3 moist, 4 or 5 dry, chroma of 4 moist and 3 or 4 dry. It has 5 to 15 percent clay (estimated). It contains 0 to 10 percent subangular gravel and 0 to 5 percent cobbles. Total rock fragments range from 0 to 15 percent.
The 2Bwb horizon has hue of 5YR moist and 7.5YR dry, value of 3 moist, 4 dry and chroma of 4 moist and dry. It has 15 to 27 percent clay (estimated). It contains 0 to 10 percent subrounded gravel, 10 to 20 percent subrounded cobbles and 0 to 5 percent subrounded stones. Total rock fragments ranges from 15 to 35 percent.
The 3Btb horizon has hue of 5YR or 7.5YR moist and dry, value of 3 moist, 4 dry and chroma of 4 moist and dry. It is cobbly loam or clay loam. It has 20 to 35 percent clay (estimated) with 5 to 10 percent subrounded gravel, 10 to 20 percent subrounded cobbles and 0 to 5 percent subrounded stones. Total rock fragments ranges from 15 to 35 percent.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Minkwell soils are on glacial moraines at elevations of 3,200 to 5,200 feet. Slopes are 0 to 50 percent. The soils formed in ash and pumice deposits overlying glacial till. The climate is characterized by cold, wet winters and cool, moist summers. The mean annual precipitation is 50 to 70 inches, falling mostly as snow. The mean annual temperature is 35 to 44 degrees F. The frost-free period is 10 to 50 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Belrick, Bott, Douthit, Haynap, and Linksterly soils. The Belrick, and Linksterly soils are on glacial moraines and are ashy. The Bott soils are on mountains and are ashy over loamy-skeletal. Douthit soils are on moraines and are ashy-skeletal. The Haynap soils are on glacial moraines and are ashy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat, recreation and watershed. Potential native vegetation is ponderosa pine, Douglas fir, snowbrush, and greenleaf manzanita.
DISTRIBUTION AND EXTENT: East slope of the Cascades in Central Oregon; MLRA 3. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Jefferson County (Upper Deschutes River Area), Oregon, 1992.
REMARKS: Diagnostic horizons and features recognized in the pedon are:
ochric epipedon - from the mineral soil surface to 10 inches (A horizon)
cambic horizon - from 11 to 24 inches (Bw horizon).
Andic soil properties - the ashy surface mantle (1 to 24 inches) has estimated glass content of 70 to 80 percent (based on data from the Belrick Series), phosphate retention of 74 to 88 percent, acid oxalate aluminum of 0.8 to 1.5 percent and acid oxalate iron of 0.9 to 1.5 percent.
Vitri- the ashy surface mantle (1 to 24 inches) has 15-bar water content of 14 percent on dried samples and 16 to 19 percent on undried samples.
Particle-size control section - (1 to 41 inches). The upper part (1 to 24 inches) has 15-bar water content of 14 percent on dried samples but ranges to 10 percent and 16 to 19 percent on undried samples. The lower part (24 to 41 inches) has 15-bar water content of 15 to 20 percent on dried samples and 25 to 30 percent on undried samples.
The A1, A2 and Bw horizons have developed in "Sand Mountain" tephra (3,440 years old). The 2Bwb and 3Btb horizons have developed in "Abbot Butte" glacial till (140-170,000 years old).
ADDITIONAL DATA: Partial laboratory data are available for this soil. Reference sample S87OR-031-005 from Jefferson County, Oregon, NSSL, Lincoln, NE, 4/89. The glass counts are assumed to be incorrect based on chemical andic soil properties tests and glass counts on geographically associated soils.