LOCATION DUNLATOP COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Ustollic Haplocryalfs
TYPICAL PEDON: Dunlatop loam - mountain park. (Colors are for dry soil unless otherwise noted.)
A--0 to 7 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure parting to moderate very fine granular; slightly hard, friable, slightly sticky and slightly plastic; 5 percent fine pebbles; medium acid; clear smooth boundary. (6 to 10 inches thick)
B/E--7 to 12 inches; brown (10YR 5/3) and yellowish brown (10YR 5/4) sandy clay loam, dark brown (10YR 3/3) and brown (7.5YR 4/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 5 percent fine pebbles; medium acid; clear wavy boundary. (4 to 8 inches thick)
Bt1--12 to 21 inches; yellowish brown (10YR 5/6) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 5 percent pebbles; strongly acid; clear smooth boundary. (6 to 12 inches thick)
Bt2--21 to 30 inches; very pale brown (10YR 7/3) and light yellowish brown (10YR 6/4) sandy clay loam, light yellowish brown (10YR 6/4) and yellowish brown (10YR 5/4) moist; moderate fine and medium subangular blocky structure; slightly hard, slightly sticky and slightly plastic; 10 percent pebbles; strongly acid; clear smooth boundary. (6 to 12 inches thick)
2C--30 to 60 inches; white (10YR 8/2) sandy clay loam, very pale brown (10YR 7/3) moist; massive, parting to moderate fine and medium plates upon drying; slightly hard, very friable, slightly sticky and slightly plastic; 10 percent pebbles; strongly acid.
TYPE LOCATION: Rio Blanco County, Colorado; area is not sectionized - approximately 1,150 feet west, and 1,200 feet north of the southeast corner of the NE1/4 of Sec. 30, T. 2 N., R. 90 W. U.S.G.S. Fawn Creek quad.; lat. 46 degrees, 6 minutes, 22 seconds N., and long. 107 degrees, 31 minutes, 8 seconds W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 37 to 42 degrees F and mean annual summer temperature ranges from 49 to 57 degrees F. These soils are noncalcareous throughout. The solum ranges from 24 to 40 inches thick. Coarse fragments range from 0 to 15 percent in the A and B horizons and are dominately less than 3 inches in diameter. Coarse fragments in the substrata range up to 35 percent and are pebble or cobble-size. The particle size control section is sandy clay loam or clay loam with 20 to 35 percent clay, 15 to 35 percent silt and 30 to 60 percent sand. The contrasting material, influenced by ash and basaltic materials, occurs mainly below 16 inches.
The A horizon has hue of 2.5Y or 10YR, value of 4 or 5, 2 or 3 moist, and chroma of 2 or 3. It is slightly acid or medium acid.
The B/E horizon has hue of 2.5Y to 7.5YR, value of 4 through 6, 3 or 4 moist, and chroma of 2 through 4.
The Bt horizons have hue of 10YR or 7.5YR, value of 4 through 7, 4 through 6 moist, and chroma of 3 through 6. They are medium acid to strongly acid.
The contrasting ash influenced 2C horizon occurs at 20 to 40 inches below the surface. It has hues of 2.5Y through 7.5YR, value of 7 or 8, 6 or 7 moist, and chroma of 2 through 4. It ranges from medium acid to very strongly acid.
COMPETING SERIES: These are the Amesmont (WY), Beardall (UT), Bramard (ID), Hub (WY), Nisula (ID), Rimton (WY), Stringam (ID), Swapps (UT), Telcher (ID), Ula (CO), and Wix (CO) soils.
Amesmont, Beardall, Swapps, Ula, and Wix soils have bedrock at depths of 20 to 40 inches. Hub and Rimton soils are slightly acid to slightly alkaline throughout. Stringam soils have a solum thickness of 42 to 56 inches. Telcher soils are neutral or slightly acid throughout. Bramard soils have mollic epipedons more than 16 inches thick and lack E horizons. Nisula soils have solums 48 to 70 inches thick.
GEOGRAPHIC SETTING: Dunlatop soils are on high mountains, side slopes, and uplands, at elevation of 9,400 to 11,200 feet. Slopes are 0 to 30 percent. The soils are formed in basalt and ash materials which overlie volcanic ash influenced materials. At the type location the mean annual precipitation is 25 to 32 inches, the majority of which comes as snow. The mean annual temperature is 35 to 38 degrees F. Frost-free season is less than 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cochetopa, Hapgood, Ripple, and Scout soils. Cochetopa soils have fine particle-size control sections. Hapgood soils are loamy-skeletal. Ripple soils lack a mollic epipedon. Scout soils have ochric epipedons and are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderate permeability.
USE AND VEGETATION: Used for livestock grazing, some timber production, wildlife habitat, and recreation. Native vegetation includes Baltic rush, Letterman needlegrass, junegrass, mountain brome, Colorado blue wildrye, Scribner wheatgrass, yarrow, aspen peavine, pussytoes, elk sedge, sneezeweed, lupine, and golden current. Scattered areas of quaking aspen, Engelmann spruce, Douglas-fir, and subalpine fir also occur.
DISTRIBUTION AND EXTENT: Mountainous areas of Western Colorado. The series is of small extent with about 3,500 acres mapped.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Flat Tops Soil Survey Area, Rio Blanco County, Colorado, 1984.
REMARKS: This series provides a concept with ash influence that the other Mollic Cryoboralfs do not have. This soil will not meet the requirements of the Andept suborder; however, it is severely affected by the underlying volcanic ash. The series name is coined from the Dunckley Flat Tops Mountain. Laboratory Sample No. is S81CO-103-001. Last updated by the state 4/94.