LOCATION ROCKBLUFF WI

Established Series
Rev. TAM-HFG
03/2021

ROCKBLUFF SERIES

The Rockbluff series consists of excessively drained soils which are deep or very deep to a paralithic contact with sandstone on valley sides on bedrock controlled uplands. These soils formed in siliceous sandy colluvium and slope alluvium and in the underlying siliceous sandy residuum from the underlying sandstone. Permeability is rapid in the sandy mantle and moderately slow or moderate in the sandstone. Slopes range from 30 to 60 percent. Mean annual precipitation is about 30 inches. Mean annual temperature is about 48 degrees F.

TAXONOMIC CLASS: Mesic, coated Typic Quartzipsamments

TYPICAL PEDON: Rockbluff loamy sand (from an area of Gaphill-Rockbluff complex, 30 to 60 percent slopes) on a slightly convex to plane northwest facing 52 percent slope in woodland at an elevation of about 960 feet. (Colors are for moist soil unless otherwise stated.)

Oe--0 to 2 inches; very dark grayish brown (10YR 3/2) moderately decomposed plant material; about 50 percent fiber and 25 percent rubbed; weak thin platy structure; very friable; strongly acid; abrupt smooth boundary. (0 to 3 inches thick)

A--2 to 4 inches; black (10YR 2/1) loamy sand, dark gray (10YR 4/1) dry; moderate fine granular structure; very friable; many fine and medium roots; about 1 percent dolomite channers; about 1 percent dolomite flagstones; moderately acid; abrupt smooth boundary. (1 to 6 inches thick)

E--4 to 9 inches; brown (10YR 4/3) loamy sand, pale brown (10YR 6/3) dry; weak thick platy structure; very friable; many fine and medium roots; about 1 percent dolomite channers and 2 percent sandstone channers; slightly acid; clear smooth boundary. (0 to 8 inches thick)

Bw--9 to 35 inches; brown (7.5YR 4/4) sand; weak coarse subangular blocky structure; very friable; common fine and medium roots; 3 percent dolomite channers and 3 percent sandstone channers; slightly acid; gradual smooth boundary. (4 to 30 inches thick)

C--35 to 52 inches; yellow (10YR 7/6) sand; single grain; loose; few very fine and fine roots; about 5 percent sandstone channers; neutral; gradual irregular boundary. (10 to 30 inches thick)

Cr--52 to 80 inches; brownish yellow (10YR 6/6), light yellowish brown (10YR 6/4), and yellowish brown (10YR 5/6) sandstone; neutral.

TYPE LOCATION: Pepin County, Wisconsin; about 2.5 miles west and 1.5 miles south of Ella; 1500 feet south and 2360 feet east of the northwest corner of sec. 32, T. 24 N., R. 14 W. USGS Ella, WI quad.; lat. 44 degrees, 31', 15" N.; long. 92 degrees, 06', 23" W.

RANGE IN CHARACTERISTICS: (Unless otherwise stated, thickness and depth are measured from the top of the mineral soil.) Depth to the base of soil development ranges from 35 to 55 inches. Depth to the paralithic contact with sandstone ranges from 40 to 80 inches. Rock fragments are both dolomite and sandstone in the slope alluvium but are just sandstone in the residuum. Volume of channers ranges from 0 to 15 percent in the upper part of the soil and from 0 to 35 percent in the lower part. Volume of flagstones ranges from 0 to 5 percent throughout the pedon. Reaction typically ranges from extremely acid to neutral in the O and A horizons and from strongly acid to neutral throughout the rest of the pedon.

The O horizon has hue of 7.5YR or 10YR or is neutral in hue. Value is 2 or 3 and chroma is 0 to 2. The O horizon is a layer of partially decomposed forest litter.

The A horizon has hue of 7.5YR or 10YR, value of 2 to 5, and chroma of 1 to 3.

The E horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 2 or 3. It is sand, fine sand, loamy sand. or loamy fine sand.

The Bw horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 3 to 6. It is sand, loamy sand, fine sand, loamy fine sand or the channery or flaggy analogs. Horizons with spodic color have pH of 6.0 or more or have less than 0.6 percent organic carbon.

The C horizon has hue of 7.5YR or 10YR, value of 5 to 8, and chroma of 2 to 8. It is sand, fine sand or the channery or flaggy analogs. Color is that of the uncoated sand grains in many pedons.

The Cr horizon has color like the C horizon described above. It is soft sandstone and is a paralithic contact but grades to a lithic contact below 60 inches.

COMPETING SERIES: These are the Evesboro, Gosil, Plymouth, Runclint, and Schaffenaker series. None of these soils have a paralithic contact in the series control section. Schaffenaker soils have a lithic contact with sandstone at 20 to 40 inches.

GEOGRAPHIC SETTING: Rockbluff soils are on valley sides of bedrock controlled uplands. Slope gradients range from 30 to 60 percent. These soils formed in siliceous sandy slope alluvium and in the underlying siliceous sandy residuum from the underlying sandstone. Mean annual precipitation ranges from 28 to 33 inches. Mean annual temperature ranges from 46 to 51 degrees F. The frost free period ranges from about 135 to 160 days. Elevation ranges from 900 to 1100 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Gaphill series. TThe well drained Gaphill soils are in landscape positions similar to those of Rockbluff soils where there is a 20 to 40 inch thick loamy mantle over the sandy residuum.

DRAINAGE AND PERMEABILITY: Excessively drained. Runoff is very rapid. Permeability is rapid in the sandy mantle and moderately slow or moderate in the sandstone.

USE AND VEGETATION: Most areas are used for woodland. Some areas are used for pastureland. Native vegetation is mixed hardwoods with some conifers. Common trees are northern pin oak, northern red oak, black oak, jack pine, red pine, and eastern white pine.

DISTRIBUTION AND EXTENT: West-central Wisconsin (MLRA M105). These soils are of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: ST. PAUL, MINNESOTA

SERIES ESTABLISHED: Pepin County, Wisconsin, 1998. Source of the name is a bluff in Pepin County.

REMARKS: This soil was mapped as steep and very steep miscellaneous areas (i.e. steep stony land, etc.) associated with the Jordan sandstone formation in M105. Typically, these soils are on valley sides below summits and shoulders which are, or were, capped with dolomite bedrock which contributed to the pH and base saturation of the upper parts of the pedon.

Diagnostic horizons and features recognized in the pedon are: ochric epipedon - 2 to 9 inches (A, E); siliceous feature - less than 10 percent weatherable minerals (.02 to 2 mm fraction); coated feature - weighted average content of silt plus clay of more than 5 percent in the particle-size control section; paralithic contact - 52 inches (Cr).

ADDITIONAL DATA: Soil Interpretation Record - WI0578.

National Cooperative Soil Survey
U.S.A.