LOCATION MONKEYCREEK OR
Tentative Series
IRD. SCW/TDT
03/2013
MONKEYCREEK SERIES
The Monkeycreek series consists of very deep, well drained soils formed in coarse-textured residuum and colluvium derived from exfoliating basalt with an influence of ash in the surface. They are on alluvial fans, footslopes, and benches. Slopes are 2 to 50 percent. The mean annual precipitation is 16 inches, and the mean annual temperature is 47 degrees F.
TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Vitrandic Haploxerolls
TYPICAL PEDON: Monkeycreek ashy sandy loam - woodland, on a 15 percent slope at an elevation of 2,350 feet. (When described on October 6, 2004, the soil was dry throughout. Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed pine needles, twigs, and dry grass
A1--1 to 6 inches; very dark brown (10YR 2/2) ashy sandy loam, dark grayish brown (10YR 4/2) dry; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine and common very fine roots; few fine and common very fine tubular pores; 10 percent gravel; slightly alkaline (pH 7.6); clear smooth boundary.
A2--6 to 21 inches; very dark grayish brown (10YR 3/2) ashy sandy loam, grayish brown (10YR 5/2) dry; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few coarse and fine and common very fine roots; few fine and common very fine tubular pores; 10 percent cobbles and 2 percent gravel; slightly alkaline (pH 7.6); gradual wavy boundary. (Combined thickness of the A horizon is 10 to 20 inches)
2Bw1--21 to 33 inches; dark brown (10YR 3/3) cobbly sandy loam, brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few fine and common very fine roots; common very fine tubular pores; 10 percent stones, 15 percent cobbles, and 5 percent gravel; slightly alkaline (pH 7.7); clear wavy boundary. (10 to 20 inches thick)
2Bw2--33 to 40 inches; dark brown (10YR 3/3) loam, brown (10YR 5/3) dry; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few fine and common very fine roots; common very fine tubular pores; 5 percent cobbles and 5 percent gravel; slightly alkaline (pH 7.8); clear wavy boundary. (5 to 20 inches thick)
2Bw3--40 to 65 inches; dark yellowish brown (10YR 3/4) loam, yellowish brown (10YR 5/4) dry; moderate medium and coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine and common very fine roots; common very fine tubular pores; 5 percent cobbles and 5 percent gravel; slightly alkaline (pH 7.8).
TYPE LOCATION: Grant County, Oregon, located about 13.5 miles NE of the town of Monument; 100 feet south and 300 feet west of the NE corner of section 7, T. 7 S., R. 29 E. (Latitude 44 degrees, 58 minutes, and 49 seconds N. and Longitude 119 degrees, 15 minutes, and 55 seconds W.)
RANGE IN CHARACTERISTICS: These soils are usually moist, but are dry in all parts of the moisture control section for 70 to 90 days consecutive days following the summer solstice. The mean annual soil temperature is 47 to 52 degrees F. Depth to bedrock is greater than 60 inches. The mollic epipedon is 20 to 30 inches thick and contains 5 to 15 percent volcanic glass and 0.4 to 0.8 percent acid oxalate extractable aluminum plus one-half iron. Hue is 7.5YR or 10YR throughout. Soil reaction is neutral or slightly alkaline throughout.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 or 2 moist and dry. It is ashy sandy loam with 8 to 18 percent clay. It has 0 to 10 percent cobbles and 0 to 10 percent gravel.
The 2Bw1 and 2Bw2 horizons have value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is sandy loam or loam with 8 to 18 percent clay. It has 0 to 10 percent stones, 0 to 15 percent cobbles, and 0 to 5 percent gravel.
The 2Bw3 horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. It is sandy loam, loam, or sandy clay loam with 15 to 25 percent clay. It has 0 to 15 percent cobbles and 0 to 15 percent gravel.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Monkeycreek soils are on alluvial fans, benches, and footslopes. Elevations range from 2,000 to 3,400 feet. Slopes are 2 to 50 percent. They formed in coarse-textured residuum and colluvium derived from exfoliating basalt with an influence of ash in the surface. The climate is characterized by cool, wet winters and hot, dry summers. The mean annual precipitation is 15 to 18 inches. The mean annual temperature is 45 to 50 degrees F., the mean July temperature is about 70 degrees F., and the mean January temperature is about 31 degrees F. The frost free period is 80 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Exfo,
Gwin,
Ninetysix,
Rockly,
Threecreeks, and
Wolot soils. Exfo and Ninetysix soils were formed in massive, exfoliating basalt. Exfo soils are very shallow to bedrock, sandy-skeletal, and are found on shoulders. Ninetysix soils are loamy-skeletal, lack an O horizon, and are found on foot slopes. Gwin and Rockly soils were formed in hard, columnar basalt and are located immediately above the massive, exfoliating basalt. Gwin and Rockly are loamy-skeletal and are shallow and very shallow, respectfully, to bedrock. Threecreeks soils have an irregular decrease in organic matter with depth, a sandy substratum, are moderately well drained, and are on flood plains. Wolot soils are ashy over loamy and are on alluvial fans or footslopes.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability
USE AND VEGETATION: These soils are used for timber production, livestock grazing, and wildlife habitat. The potential native vegetation is Ponderosa pine, western needlegrass, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: East-central Oregon. MLRA 10. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Grant County, Oregon. 2006. The name is derived from Monkey Creek, a prominent stream along the North Fork of the John Day River near the Grant-Morrow County line.
REMARKS: Diagnostic horizons and features in this pedon are:
Mollic epipedon (pachic) - the zone from the surface to 21 inches (A1 and A2 horizons)
Vitrandic feature - the zone from the surface to 21 inches (A1 and A2 horizons)
Cambic horizon - the zone from 21 to 65 inches (2Bw1, 2Bw2, and 2Bw3 horizons)
Particle-size control section - the zone from 10 to 40 inches (lower part of the A2, 2Bw1, and 2Bw2 horizons)
National Cooperative Soil Survey
U.S.A.