LOCATION SINOPAH MT
Tentative Series
Rev. EMR-JMS-RJS
05/2017
SINOPAH SERIES
The Sinopah series consists of very deep, very poorly drained soils formed in decomposed herbaceous plant material and layered volcanic ash. Sinopah soils are on fens within glacial-valley floors. Slopes range from 0 to 2 percent. The mean annual precipitation is about 750 mm and the mean annual air temperature is about 4.0 degrees C.
TAXONOMIC CLASS: Euic Fluvaquentic Cryosaprists
TYPICAL PEDON: Sinopah mucky peat in a fen with a 2 percent slope, at an elevation of 1,114 meters. (Colors are for moist soil unless otherwise noted.)
Oe--0 to 36 cm; very dark brown (10YR 2/2) mucky peat, very dark grayish brown (10YR3/2) dry; 60 percent fibers, 25 percent rubbed; many very fine roots; many very fine irregular pores; slightly acid (pH 6.2); clear smooth boundary.
Oa--36 to 77 cm; black (10YR 2/1) muck, very dark gray (10YR3/1) dry; 20 percent fibers, 5 percent rubbed; many very fine roots; many very fine irregular pores; neutral (pH 6.6); abrupt smooth boundary.
C--77 to 94 cm; light olive brown (2.5Y 5/4) ashy silt loam, light yellowish brown (2.5Y 6/4) dry; massive; friable, slightly hard, slightly sticky and nonplastic; many very fine roots; common very fine irregular pores; neutral (pH 6.6); abrupt smooth boundary.
O'a--94 to 127 cm; very dark gray (10YR 3/1) muck, very dark grayish brown (10YR3/2) dry; 10 percent fibers, 5 percent rubbed; very sticky and slightly plastic; many very fine roots; many very fine irregular pores; neutral (pH 6.6); clear smooth boundary.
Cg1--127 to 136 cm; greenish gray (10Y 6/1) silt loam, light gray (10YR 7/1) dry; massive; firm, moderately hard, moderately sticky and moderately plastic; few very fine roots; few very fine irregular pores; 5 percent gravel; neutral (pH 6.8); clear smooth boundary.
Cg2--136 to 150 cm; gray (N 6/) silt loam, light gray (N 7/) dry; massive; firm, moderately hard, moderately sticky and moderately plastic; few very fine roots; few very fine irregular pores; 10 percent gravel; neutral (pH 6.8).
TYPE LOCATION: Flathead County, Montana; located about 5 meters north and 100 meters west of the southeast corner of sec. 18, T. 33N., R. 19W; Camas Ridge West topographic quadrangle; UTM Zone 12, 272721e, 5390368n. NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 3.0 to 6.5 degrees C.
Histic epipedon: 60 to 100 cm thick
Depth to volcanic ash and/or other mineral layers: 60 to 100 cm; thickness of the various mineral strata within the first 100 cm is 15 to 30 cm
Depth to a seasonally high water table: 0 to 15 cm; water may be ponded in the spring and early summer.
Note: Occasionally a saturated Oi horizon (10 cm or less thick) is found at the surface with slightly decomposed mosses and fibers. Organic layers are mostly highly decomposed mosses and sedges. Wood fragment content is typically less than 5 percent.
Oe horizon
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 or 2 dry or moist
Reaction: pH 5.4 to 7.2
Thickness: 0 to 40 cm
Oa horizon
Value: 2 or 3 dry or moist
Chroma: 1 or 2 dry or moist
Reaction: pH 5.6 to 7.2
Thickness: 30 to 60 cm
C horizon
Hue: 10YR or 2.5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 1 to 4 dry or moist
Clay content: 8 to 20 percent
Rock fragments: 0 to 5 percent gravel
Reaction: pH 5.8 to 7.4
Thickness: 10 to 25 cm
O'a horizon
Value: 2 or 3 dry or moist
Chroma: 1 or 2 dry or moist
Thickness: 30 to 60 cm
Cg1, Cg2 horizons
Hue: 10YR, 2.5Y, N, or any of the gleyed hues (5Y, 10Y, 5G, 10G, etc.)
Value: 5 to 7 dry or moist
Chroma: 0 to 2 dry or moist
Texture (less than 2 mm fraction): silt loam or ashy silt loam
Clay content: 8 to 15 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Reaction: pH 6.6 to 7.6
COMPETING SERIES:
Anipash (WA): have greater than 35 percent rock fragments in the C horizon
Chichantna (AK): do not have ashy textures in any mineral horizon
Ghost (WA): have a Bg horizon
Tyonek (AK): have 5 to 25 percent wood fragments in the control section
GEOGRAPHIC SETTING:
Landform: fens within glacial-valley floors
Elevation: 1,000 to 1,300 meters
Slope: 0 to 2 percent
Parent material: decomposed herbaceous plant material and layered volcanic ash
Climate: long, cold winters; moist springs; short warm summers with May and June receiving the most precipitation
Mean annual precipitation: 640 to 900 mm
Mean annual air temperature: 2.0 to 6.0 degrees C.
Frost-free period: 45 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained and 5.0 to 50 um/sec.
USE AND VEGETATION: These soils are in organic wet meadows that are used mainly for wildlife. They are saturated much of the year and covered with a blanket of mosses. The herbaceous vegetation is dominated by woollyfruit sedge, Northwest Territory sedge, Nebraska sedge, and minor amounts of purple marshlocks and marsh skullcap. Shrub species such as willows, bog birch, and western Labrador tea are sometimes found near the perimeter of these meadows.
DISTRIBUTION AND EXTENT: Sinopah soils are of limited extent in northern Montana. MLRA 43A and 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Flathead County, Montana. This soil is named for a mountain in Glacier National Park.
REMARKS:
Diagnostic horizons and features recognized in this pedon include:
Histic epipedon: 0 to 77 cm (Oe, Oa horizons)
Volcanic ash layer: 77 to 94 cm (C horizon)
Sapric soil material: 36 to 77 cm; 94 to 127 cm (Oa, O'a horizons)
Aquic conditions: 0 to greater than 150 cm ((Oe, Oa, C, O'a, Cg1, Cg2 horizons)
Particle-size control section: 0 to 130 cm (Oe, Oa, C, O'a, part of the Cg1 horizons).
Sinopah soils have a cryic temperature regime and an aquic moisture regime.
Taxonomic version: Keys to Soil Taxonomy, Twelfth Edition, 2014.
National Cooperative Soil Survey
U.S.A.