LOCATION GOLDMINE SD+WY
Established Series
Rev. DWJ, DJB, JWW
11/2020
GOLDMINE SERIES
The Goldmine series consists of very deep, well drained soils that formed in colluvium and residuum derived from igneous rocks. Goldmine soils are on mountain hillslopes. Slopes range from 3 to 75 percent. Mean annual precipitation is about 735 mm (29 inches) and the mean annual temperature is about 7 degrees C (45 degrees F).
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Typic Palecryolls
TYPICAL PEDON: Goldmine loam, on a west-northwest facing, linear slope of 24 percent, in a mixed coniferous and deciduous woodland community at an elevation of about 1900 meters (6234 feet). (Colors are for moist soil unless otherwise noted. When described on July 15, 2005 the soil was moist from the mineral soil surface to about 61 cm (24 inches) and dry below.)
Oi--0 to 2 cm (0 to 1 inch); relatively undecomposed pine needles, twigs and other wood fragments, aspen leaves and twigs, and grass leaves and stems; slightly acid.
Oe--2 to 5 cm (1 to 2 inches); slightly to moderately decomposed woody residue from pine trees and aspen, and herbaceous plant material; slightly acid. (Combined thickness of the O horizon is 1 to 5 cm (1 to 2 inches))
A--5 to 13 cm (2 to 5 inches); black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak medium and strong fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, and medium and common coarse roots; about 5 percent angular igneous rock fragments as channers, gravel, and cobbles; neutral; abrupt smooth boundary. (7 to 15 cm (3 to 6 inches) thick)
AE--13 to 30 cm (5 to 12 inches); very dark grayish brown (10YR 3/2) channery loam, grayish brown (10YR 5/2) dry; weak fine and medium platy structure parting to weak medium and moderate fine subangular blocky; soft, friable, nonsticky and nonplastic; common very fine, fine, medium and coarse roots; about 10 percent angular igneous channers and 5 percent subangular gravel; slightly acid; clear wavy boundary. (10 to 18 cm (4 to 7 inches) thick)
E--30 to 51 cm (12 to 20 inches); dark grayish brown (10YR 4/2) channery loam, light gray (10YR 7/2) moist; moderate medium platy structure parting to moderate fine and medium subangular blocky; soft, friable, nonsticky and nonplastic; common very fine and few fine, medium and coarse roots; about 20 percent angular igneous channers and 10 percent subangular gravel; slightly acid; gradual wavy boundary. (20 to 51 cm (8 to 20 inches) thick)
E/Bt--51 to 74 cm (20 to 29 inches); about 70 percent dark grayish brown (10YR 4/2) very channery loam (E), light gray (10YR 7/2) dry, and 30 percent dark yellowish brown (10YR 4/4) very channery clay loam (Bt), light yellowish brown (10YR 6/4) dry; moderate fine and medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few fine and medium roots; about 30 percent faint yellowish brown (10YR 5/6) clay films on ped faces and rock fragments (Bt part); about 35 percent angular igneous channers and 5 percent flagstones; slightly acid; gradual wavy boundary. (0 to 33 cm (0 to 13 inches) thick)
Bt1--74 to 94 cm (29 to 37 inches); yellowish brown (10YR 5/4) very channery clay loam, light yellowish brown (10YR 6/4) dry; weak coarse and moderate medium subangular blocky structure; slightly hard, firm, moderately sticky and slightly plastic; about 50 percent faint dark yellowish brown (10YR 4/6) clay films on ped faces and 20 percent faint dark yellowish brown (10YR 4/6) clay films on rock fragments; few medium and fine roots; about 60 percent angular igneous rock fragments, of which 40 percent are channers, 10 percent cobbles, and 10 percent are flagstones; slightly acid; gradual irregular boundary.
Bt2--94 to 152 cm (37 to 60 inches); yellowish brown (10YR 5/4) extremely channery clay loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky structure; slightly hard, firm, moderately sticky and slightly plastic; few medium and fine roots; about 50 percent faint dark yellowish brown (10YR 4/6) clay films on ped faces and 15 percent faint dark yellowish brown (10YR 4/6) clay films on rock fragments; about 85 percent igneous rock fragments, of which 65 percent are angular channers and 20 percent are flagstones; neutral. (Combined Bt horizons greater than 50 cm (20 inches) thick)
TYPE LOCATION: Lawrence County, South Dakota; about 4.8 km (3 miles) west of the city of Lead; located about 400 m (1,310 ft) east and 424 m (1,390 ft) south of the northwest corner of Sec. 35, T. 5 N., R. 2 E.; Lead USGS quad; 44 degrees 21 minutes 18.7 seconds N. latitude and 103 degrees 50 minutes 40.6 seconds W. longitude, NAD 83.
RANGE IN CHARACTERISTICS:
Particle-size control section (weighted average):
Clay content: 28 to 35 percent
Sand content: 10 to 25 percent
Rock fragments: 35 to 90 percent igneous rocks; 30 to 65 percent of which are angular channers, 5 to 15 percent subangular gravel, 0 to 40 percent angular cobbles, and 0 to 20 percent angular flagstones.
A horizon:
Hue: 10YR
Value: 2, 3 or 4 dry
Chroma: 1 or 2
Texture: L, CN-L, GR-L
Clay content: 12 to 22 percent
Rock fragments: 5 to 25 percent
Reaction: Neutral or slightly acid
AE horizon (EA in some pedons):
Hue: 10YR
Value: 3, 4 or 5 dry
Chroma: 2
Texture: CN-L, GR-L, CNV-SIL, L
Clay content: 12 to 22 percent
Rock fragments: 10 to 35 percent
Reaction: Neutral or slightly acid
E horizon:
Hue: 10YR
Value: 4 to 6 moist, 6 or 7 dry
Chroma: 2 or 3
Texture: CN-L, CNV-L, GRV-L, CBV-L
Clay content: 10 to 20 percent
Rock fragments: 20 to 55 percent
Reaction: Neutral to medium acid
The E/Bt horizon (Bt/E in some pedons) has combined properties of the E and Bt horizons. It typically consists of about 60 percent E horizon material and 40 percent Bt horizon material.
Bt horizon:
Hue: 10YR
Value: 5 or 6 moist, 6 or 7 dry
Chroma: 3 to 6
Texture: CNV-CL, CNX-CL, CBX-SICL
Clay content: 28 to 35 percent weighted average; upper part of horizon may have 35 to 40 clay
Rock fragments: 35 to 90 percent
Reaction: Neutral or slightly acid
COMPETING SERIES: These are the
Lucky Star and
Nordic series. Lucky Star soils have a hue redder than 10YR in the argillic horizon. Nordic soils lack an E or E/B horizons.
GEOGRAPHIC SETTING:
Parent material: Colluvium or residuum derived from Tertiary-aged igneous rock
Landform: Gently sloping to steep mountain hillslopes
Slopes: 3 to 75 percent
Elevation: 1575 to 2125 meters
Mean annual air temperature: 6 to 8 degrees F
Mean annual precipitation: 650 to 760 mm
Precipitation pattern: In most years, about half the annual precipitation occurs as snow or rain during the period March through June. T
Frost-free period: 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Grizzly and
Virkula series. The Grizzly soils do not have mollic epipedons and are on similar landscape positions. Virkula soils are fine-silty and are on linear to concave slopes below Goldmine soils.
DRAINAGE AND PERMEABILITY: Well drained. Moderately high saturated hydraulic conductivity.
USE AND VEGETATION: Goldmine soils formed under a mixed coniferous and deciduous forest and are utilized for livestock grazing, wildlife habitat, timber production, and suburban development. The native vegetation consists of an overstory of ponderosa pine, Black Hills spruce, and aspen; understory species include bearberry, snowberry, ground juniper, Oregon grape, brachen fern, thimbleberry, beebalm, false Solomonseal, bearded wheatgrass, roughleaf ricegrass, and Timothy.
DISTRIBUTION AND EXTENT: Goldmine soils occur in the Black Hills of South Dakota and Wyoming; LRR G, MLRA 62; the series is of small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Salina, Kansas.
SERIES ESTABLISHED: Extensive revision of the Soil Survey of Lawrence County, South Dakota. The name is coined from the abundance of contemporary and historic mining activity in the area of the type location.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Soil moisture: Typic udic
Particle-size control section: Zone from 74 to 124 cm (29 to 49 inches). (Bt horizons)
Mollic epipedon: Zone from 5 to 30 cm (2 to 12 inches). (A and AE horizons)
Albic horizon: Zone from 30 to 51 cm (12 to 20 inches). (E horizon)
Glossic horizon: Zone from 51 to 74 cm (20 to 29 inches). (E/Bt horizon)
Argillic horizon: Zone from 74 to 152 cm (29 to 60 inches). (Bt1 and Bt2 horizons)
Taxonomic Version - Keys to Soil Taxonomy, Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.