LOCATION MARKLEPASS MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Natrixeralfs
TYPICAL PEDON: Marklepass silty clay loam, rangeland (colors are for dry soil unless otherwise noted.)
Ap1--0 to 4 inches; light gray (10YR 7/2) silty clay loam, dark grayish brown (10YR 4/2) moist; moderate coarse platy structure parting to weak fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots and common fine roots; many fine vesicular pores and common very fine vesicular pores; strongly alkaline (pH 8.8); abrupt smooth boundary.
Ap2--4 to 9 inches; light gray (10YR 7/2) silty clay loam, dark grayish brown (10YR 4/2) moist; moderate medium subangular blocky structure parting to weak medium granular, slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots and common fine roots; common fine discontinuous tubular pores and few very fine and medium discontinuous tubular pores; strongly alkaline (pH 8.8); clear wavy boundary. (Combined thickness of the A horizons is 5 to 9 inches.)
Btn/E--9 to 14 inches; B part (60 percent) very pale brown (10YR 7/3) and brown (10YR 4/3) moist; E part (40 percent) light gray (10YR 7/2) and grayish brown (10YR 5/2) moist silty clay loam; strong coarse columnar structure parting to moderate medium subangular blocky; slightly hard, friable, sticky and plastic; common very fine and fine roots; few very fine continuous tubular pores and common fine and medium continuous tubular pores; common prominent clay films on faces of peds; common faint organic stains on faces of peds; strongly alkaline (pH 8.8); clear irregular boundary. (0 to 5 inches thick)
Btn--14 to 20 inches; pale brown (10YR 6/3) and very pale brown (10YR 7/3) crushed, brown (10YR 5/3) and yellowish brown (10YR 5/4) crushed, moist; silty clay loam; moderate coarse prismatic structure parting to strong medium angular blocky; hard, firm, very sticky and very plastic; few medium roots and common very fine and fine roots; few very fine and medium tubular pores; continuous distinct gray (10YR 5/1) organic stains on faces of peds and in pores; distinct continuous clay films on faces of peds and in pores; very strongly alkaline (pH 9.2); abrupt smooth boundary. (5 to 17 inches thick)
Bkn--20 to 34 inches; very pale brown (10YR 8/3) silty clay loam, pale brown (10YR 6/3) moist; massive; slightly hard, friable, sticky and plastic; few very fine and fine roots; few fine threads of lime; violently effervescent; very strongly alkaline (pH 9.4); gradual wavy boundary. (8 to 20 inches thick)
BCn--34 to 60 inches; very pale brown (10YR 8/3) silty clay loam, pale brown (10YR 6/3) moist; massive; very hard, firm, sticky and plastic; slightly effervescent; very strongly alkaline (pH 9.2); gradual wavy boundary.
TYPE LOCATION: Lake County, Montana; 1,400 feet north and 700 feet east of the SW corner of sec. 28, T. 22 N., R. 23 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 43 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to Bk horizon - 10 to 25 inches.
Some pedons have an E/Bt horizon or an E horizon.
Ap horizon - Hue: 10YR or 2.5Y
Value: 5, 6, 7, or 8 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Texture: silt loam or silty clay loam
Clay content: 18 to 40 percent
EC: less than 4 mmhos/cm
SAR: 13 to 75
Reaction: pH 8.5 to 9.6
Btn/E horizon - Hue: 10YR or 2.5Y
Value: B part 6 or 7, E part 7 or 8 dry; B part 4 or 5, E part 5 or 6 moist
Chroma: B part 3 or 4, E part 2 or 3
Clay content: 27 to 40 percent
EC: less than 4 mmhos/cm
SAR: 45 to 75
Reaction: pH 8.5 to 9.6
Btn horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: silty clay loam or silty clay
Clay content: 35 to 60 percent
EC: less than 4 mmhos/cm
SAR: 45 to 120
Reaction: pH 8.5 to 9.6
Bkn horizon - Hue: 10YR or 2.5Y
Value: 6, 7, or 8 dry; 5, 6, or 7 moist
Chroma: 2, 3, or 4
Texture: silty clay loam or silty clay
Clay content: 30 to 50 percent
EC: 2 to 8 mmhos/cm
SAR: 45 to 100
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 8.5 to 9.6
BCn horizon - Hue: 10YR or 2.5Y
Value: 7 or 8 dry; 5, 6, or 7 moist
Chroma: 2, 3, or 4
Texture: silty clay loam or silty clay
Clay content: 30 to 50 percent
EC: less than 2 mmhos/cm
SAR: 13 to 100
Reaction: pH 8.5 to 9.6
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - dissected alluvial fans, stream terraces, lake plains and terraces.
Elevation - 2,500 to 3,000 feet.
Slope- 0 to 4 percent.
Parent material - alluvium derived from lake sediments.
Climate - long, cold winters; moist springs and falls; warm, dry summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 41 to 45 degrees F.
Frost-free period - 105 to 125 days.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Marklepass soils are used mainly as rangeland. Potential native vegetation is alkali bluegrass, basin wildrye, alkali sacaton, and western wheatgrass.
DISTRIBUTION AND EXTENT: The series is inextensive in northwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lake County, Montana, 1991; proposed in Lake County, Montana, 1982.
REMARKS: Soil Interpretation Record: MT0750. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 9 inches (Ap1, Ap2 horizons); a Bt horizon from 9 to 20 inches (Btn/E, Btn horizons); a horizon of lime accumulation from 20 to 34 inches (Bkn horizon). A particle-size control section from 9 to 20 inches (Btn/E, Btn horizon). Marklepass soils have a frigid temperature regime and a xeric moisture regime bordering on aridic.
ADDITIONAL DATA: Lab sample S81MT-047-500.