LOCATION NORBECK SDTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Haplic Glossudalfs
TYPICAL PEDON: Norbeck gravelly loam, on a southeast facing, slightly concave slope of 32 percent, in a coniferous woodland community at an elevation of 5,120 feet. (Colors are for moist soil unless otherwise noted)
Oi--0 to 1 inch; undecomposed pine forest litter. (0 to 2 inches thick)
A--1 to 3 inches; very dark brown (10YR 2/2) gravelly loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; about 20 percent subangular granitic gravel; neutral; abrupt smooth boundary. (0 to 3 inches thick)
E--3 to 13 inches; brown (10YR 5/3) gravelly loam, very pale brown (10YR 7/3) dry; weak fine platy structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; about 20 percent subangular granitic gravel; moderately acid; abrupt smooth boundary. (7 to 14 inches thick)
Bt/E--13 to 19 inches; about 60 percent dark yellowish brown (10YR 4/4) gravelly clay loam, light yellowish brown (10YR 6/4) dry (Bt), and 40 percent brown (10YR 5/3) gravelly loam, very pale brown (10YR 7/3) dry (E); moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; about 30 percent subangular granitic gravel; slightly acid; gradual wavy boundary. (3 to 12 inches thick)
Bt1--19 to 24 inches; dark yellowish brown (10YR 4/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; weak medium prismatic structure parting to moderate medium and fine subangular blocky; hard, friable, slightly sticky and slightly plastic; common distinct clay films on vertical faces of peds; about 40 percent subangular granitic gravel; slightly acid; gradual wavy boundary.
Bt2--24 to 39 inches; yellowish brown (10YR 5/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; weak medium prismatic structure parting to moderate medium subangular blocky; hard, friable; slightly sticky and slightly plastic; many distinct clay films on all ped faces; about 45 percent angular granitic gravel; neutral; gradual wavy boundary.
Bt3--39 to 45 inches; yellowish brown (10YR 5/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; weak coarse prismatic structure parting to weak medium subangular blocky; hard, friable, slightly sticky and slightly plastic; common distinct clay films on all ped faces; about 50 percent subangular granitic gravel and cobble; neutral; gradual wavy boundary.
Bt4--45 to 51 inches; yellowish brown (10YR 5/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; weak coarse subangular blocky structure; very hard, firm, slightly sticky and slightly plastic; few faint clay films on vertical ped faces; about 55 percent subangular granitic gravel and cobble; neutral; gradual wavy boundary. (Combined Bt horizons 15 to 38 inches thick)
BC--51 to 60 inches; yellowish brown (10YR 5/4) very gravelly loam, light yellowish brown (10YR 6/4) dry; very weak coarse subangular blocky structure; very hard, firm, slightly sticky and slightly plastic; about 60 percent subangular granitic gravel and cobble; neutral.
TYPE LOCATION: Custer County, South Dakota; about 7 miles northeast of Custer; located about 1,650 feet north and 1,400 feet east of the southwest corner of sec. 1, T. 3 S., R. 5 E.; Iron Mountain, South Dakota USGS quadrangle; 43 degrees 48 minutes 53 seconds N. latitude and 103 degrees 28 minutes 27 seconds W. longitude, NAD 1983.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 43 to 47 degrees F
Mean summer soil temperature: 52 to 56 degrees F
Depth to lithic or paralithic contact: 40 to 60 inches or more to consolidated granite
Depth to albic horizon: 0 to 3 inches
Depth to argillic horizon: 7 to 18 inches
Depth to glossic horizon: 7 to 14 inches
Thickness of the glossic horizon: 3 to 12 inches
Particle-size control section (weighted average):
Clay content: 25 to 35 percent
Sand content: 15 to 30 percent
Rock fragments: 35 to 60 percent angular, subangular, or subrounded gravel and/or cobble; fragments consist of granite, quartzite, metaquartzite, siliceous schist, and traces of other metacrystalline rocks.
A horizon:
Hue: 10YR
Value: 2 or 3 moist, 4 to 6 dry
Chroma: 1 or 2
Texture: Loam or sandy loam
Clay content: 15 to 25 percent
Rock fragments: 10 to 30 percent gravel, and 0 to 20 percent cobbles
Reaction: 6.1 to 7.3
E horizon:
Hue: 10YR
Value: 4 to 6 moist, 5 to 8 dry
Chroma: 2 or 3
Texture: Loam or sandy loam
Clay content: 15 to 25 percent
Rock fragments: 10 to 35 percent gravel, and 0 to 20 percent cobbles
Reaction: 5.6 to 7.3
Bt horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 moist, 5 or 6 dry
Chroma: 3 or 4
Texture: Loam or clay loam
Clay content: 25 to 35 percent
Rock fragments: 35 to 55 percent gravel and 0 to 30 percent cobbles
Reaction: 6.1 to 7.3
BC horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 moist, 5 or 6 dry
Chroma: 3 or 4
Texture: Sandy loam, loam, sandy clay loam or clay loam
Clay content: 18 to 32 percent
Rock fragments: 30 to 50 percent gravel and 10 to 30 percent cobbles
Reaction: 6.6 to 7.3
Some pedons have a C horizon with properties similar to the BC horizon.
COMPETING SERIES: These are the Ribhill and Rumplecreek series. Ribhill soils are moderately deep. Rumplecreek soils have a frost-free period of less than 90 days and formed in till.
GEOGRAPHIC SETTING:
Parent material: Residuum or colluvium derived from granite or mixed granite and metamorphic sources such as metaquartzite and siliceous schist.
Landform: Mountain tops, flanks, and bases
Slopes: 2 to 60 percent
Elevation: 4,600 to 7,200 feet
Mean annual air temperature: 41 to 45 degrees F
Mean annual precipitation: 20 to 26 inches
Precipitation pattern: In most years, half or more of the annual precipitation occurs as snow and rain from March through July.
Frost-free period: 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buska, Cordeston (micaceous), Pactola and Virkula soils. Buska soils contain 25 to 40 percent mica (in the 0.02 to 2.0 mm fraction) by weight in the particle size control section and are on similar positions as Norbeck soils. Cordeston (micaceous) and Virkula soils contain less than 35 percent rock fragments in the control section and are below Norbeck soils on the landscape. Pactola soils formed in residuum or colluvium derived from metamorphic rocks (primarily schist and slate), contain flat rock fragments (channers and flagstones), and typically contain less than 15 percent fine and coarser sand in the fine-earth fraction. They occur on similar landscape positions.
DRAINAGE AND PERMEABILITY: Well drained, slow to medium runoff, moderately high saturated hydraulic conductivity.
USE AND VEGETATION: Norbeck soils are used for timber production, wildlife habitat, recreation, and livestock grazing. Native vegetation consists of an overstory of ponderosa pine and aspen; understory species consist of bearberry, common juniper, Oregon grape, bluegrass, Columbia needlegrass, and sedges.
DISTRIBUTION AND EXTENT: Norbeck soils occur in the Black Hills of South Dakota and Wyoming. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES PROPOSED: Update Soil Survey of Lawrence County, South Dakota, 2005. The name is taken from the wildlife preserve in the vicinity of the type location.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 13 to 33 inches. (Bt/E, Bt1, and Bt2 horizons)
Ochric epipedon: The zone from 0 to 13 inches. (Oi,A and E horizon)
Albic horizon: The zone from 3 to 13 inches. (E horizon)
Glossic horizon: The zone from 13 to 19 inches. (Bt/E horizon)
Argillic horizon: The zone from 13 to 51 inches. (Bt/E, Bt1, Bt2, Bt3, and Bt4 horizons)
Remarks: The Norbeck series replaces the Mocmont series mapped in the Black Hills parts of Custer and Pennington Counties in South Dakota
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomic Version: Keys to Soil Taxonomy, Ninth Ed., 2003
ADDITIONAL DATA: A typical pedon will be excavated, described to 80 inches, and sampled for complete characterization data in August, 2005.