LOCATION FLORISSANT COTentative Series
TAXONOMIC CLASS: Fine, smectitic Ustic Argicryolls
TYPICAL PEDON: Florissant loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; strong fine granular structure; soft, very friable, slightly sticky, slightly plastic; 10 percent fine and very fine angular gravel; noncalcareous; neutral (pH 6.8); clear smooth boundary. (3 to 8 inches thick)
B1--4 to 8 inches; dark brown (10YR 4/3) light clay loam, very dark brown (10YR 3/3) moist; strong fine subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; peds are very hard; thin wax-like patches on faces of peds; 10 percent fine and very fine angular gravel; noncalcareous; neutral (pH 7.0); clear smooth boundary. (0 to 6 inches thick)
B2t--8 to 18 inches; brown (10YR 5/3) heavy clay loam, dark brown (10YR 4/3) moist; moderate medium prismatic structure that parts to medium angular blocks; slightly hard, very friable, sticky, plastic; peds are extremely hard; thin continuous wax-like coatings on the faces of peds and wax-like coatings and fillings on the inside of root channels and pores; wax like rims around the entrance of soil pores; 5 percent fine and very fine angular gravel; noncalcareous; mildly alkaline (pH 7.4); clear smooth boundary. (5 to 19 inches thick)
B3--18 to 22 inches; light olive brown (2.5Y 5/3) light clay loam, olive brown (2.5Y 4/3) moist; weak medium prismatic structure that parts to medium angular and subangular blocks; slightly hard, very friable, slightly sticky, slightly plastic; peds are very hard; thin glossy patches on faces of peds and discontinuous glossy coatings on the inside of root channels and pores; 10 percent fine and very fine angular gravel; noncalcareous; mildly alkaline (pH 7.8); clear wavy boundary. (3 to 6 inches thick)
IICcam--22 to 31 inches; pale olive (5Y 6/3) gravelly sandy loam, olive (5Y 5/3) moist; few small faint brown (10YR 5/3) moist mottles; massive; extremely hard, very firm, nonsticky, nonplastic; visible secondary calcium carbonate occurring as concretions in thin seams and streaks; 15 percent fine and very fine angular gravel; calcareous and with visible secondary calcium carbonate in the upper part but noncalcareous and without accumulations of carbonates in the lower part; can be dug with difficulty with a spade when dry and breaks out into large irregular extremely hard clods that retain a firm consistence when moist; mildly alkaline and moderately alkaline; abrupt wavy boundary. (4 to 23 inches thick)
IIIC--31 to 40 inches; interlayered bentonite, volcanic ash, pumice, and old lacustrine materials.
TYPE LOCATION: Teller County, Colorado; on west side of State Highway 143, about 200 feet north of turn in road, 0.4 mile south of junction with U.S 24, Sec. 12, T. 13 S., R. 71 W.
RANGE IN CHARACTERISTICS: Depth to uniformly calcareous material normally ranges from 6 to 30 inches and is not shallower than the upper 3 inches of the B2t horizon. Depth to the paralithic contact ranges from 20 to 40 inches. Depth to the base of the argillic horizon ranges from 15 to 30 inches. Depth to continuous subhorizons of visible secondary calcium carbonate and/or sulfate ranges from 15 to 30 inches. A major part of the solum and C horizons above the paralithic contact has hue of 7.5YR or yellower. Mottling within the control section not due to segregation of lime ranges from mottling to a few faint mottles with chroma of more than 2 in both matrix and mottling. Rock fragments range from 0 to 15 percent by volume in a major part of the solum and C horizon above the paralithic contact. These are mainly 1/8 to 1 inch in diameter. Sand and silt fractions should contain about 2 percent or more of well weathered volcanic ash, glass or pumice or the clay fraction should contain enough allophanic clay so that cation exchange capacity exceeds 100 millequivalents per 100 grams of clay. These soils are dry in some part of the moisture control section for some time in most years.
The A horizon has hue of 5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3. It is neutral or mildly alkaline (1:5 dilution unbuffered organic dye).
The B2t horizon has hue of 5Y through 7.5YR, value of 5 through 7 dry, 3 through 6 moist, and chroma of 1 through 6. Subhorizons redder than 7.5YR occur in some pedons. This horizon is typically heavy clay loam or light clay but clay ranges from 35 to 50 percent, silt from 10 to 45 percent, and sand from 15 to 50 percent with more than 15 percent being fine or coarser sand. It ranges from neutral to moderately alkaline (1:5 dilution unbuffered organic dye).
The C horizon has hue of 5Y through 7.5YR. Subhorizons redder than 7.5YR occur in some pedons. This horizon is moderately or strongly alkaline (1:5 dilution unbuffered organic dye). Calcium carbonate of the fine earth ranges from 4 to 14 percent.
COMPETING SERIES: These are the Arling, Prinkert, Brolliar, Buckskin, Getta, Gothic, Gurney, Heath, Jerry, Judy, Little Horn, Mayoworth, Needleton, Owen Creek, Segal, Sessions, Trout Creek, Waters, and Youman series. Arling, Brinkert, Buckskin, Gothic, Gurney, Heath, Jerry, Needleton, Segal, Sessions, and Youman soils lack a paralithic contact at depths of less than 40 inches. Brolliar, Getta, Judy, Little Horn, and Waters soils have a lithic contact at depths of less than 40 inches. Mayoworth, Owen Creek, and Trout Creek soils lack indurated Cca horizons.
GEOGRAPHIC SETTING: The Florissant soils are on nearly level to slightly concave or depressional lake plains or basins. Slopes typically range from about 0 to 4 percent or more. The soil formed in moderately thin calcareous, lacustrine deposits of old age strongly influenced by volcanic ash, pumice, and bentonite. At the type location the mean annual precipitation is about 18 inches with peak periods of precipitation in the spring and early summer months. Mean annual temperature is 38 degrees F., and mean summer temperature is 57 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Edloe and High Park soils. Edloe soils have an albic horizon, lack a mollic epipedon, and have a lithic contact. High park soils lack a paralithic contact at depths of less than 40 inches, and are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well to moderately well drained; slow to very slow runoff; moderate to slow permeability.
USE AND VEGETATION: Used as grazing land or recreation areas. Native vegetation is sage, western wheatgrass, and blue grama.
DISTRIBUTION AND EXTENT: Cenrtal Colorado. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Lakewood, Colorado
SERIES PROPOSED: Teller Park Soil Conservation District, Teller County, Colorado, 1943.
REMARKS: Last updated by the state 1/73.