LOCATION QUIETUS MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Typic Argicryolls
TYPICAL PEDON: Quietus loam - timbered. (Colors are for dry soil unless otherwise noted.)
0e--0 to 2 inches; partly decomposed matted spruce and fir needles and twigs. (1 to 3 inches thick)
A--2 to 5 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; light brownish gray (10YR 6/2) coating of clear sand and silt grains on peds; strong thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; slightly acid (pH 6.1); clear smooth boundary. (2 to 4 inches thick)
Bt1--5 to 9 inches; brown (10YR 5/3) heavy loam, dark yellowish brown (10YR 3/4) moist; weak medium prismatic structure that separates to weak fine blocks; hard, friable, slightly sticky and moderately plastic; common very fine roots; many very fine tubular pores; common clear sand and silt grains coating the surfaces of the larger peds; thin clay bridgings between sand grains and thin clay coatings in root channels; slightly acid (pH 6.1); gradual wavy boundary.
Bt2--9 to 13 inches; brown (10YR 4/3) heavy clay loam, dark yellowish brown (10YR 3/4) moist; weak medium prismatic structure that separates to moderate medium blocks, very hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; very thin continuous clay film coating the peds; slightly acid (pH 6.2); diffuse wavy boundary.
Bt3--13 to 18 inches; brown (10YR 5/3) gravelly heavy loam, brown (10YR 4/3) moist; weak fine blocky structure; hard, friable, moderately sticky and moderately plastic; few very fine roots; common very fine tubular pores; thin clay bridgings between the sand grains and on walls of pores; 20 percent fine limestone gravel by volume; neutral (pH 7.0); gradual wavy boundary. (Bt horizon is 10 to 15 inches thick.)
C--18 to 29 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 5/3) moist; massive; hard friable, slightly sticky and moderately plastic; few very fine roots; 40 percent dolomite gravel by volume; slightly alkaline (pH 7.4); abrupt wavy boundary. (8 to 15 inches thick)
R--29 inches; shattered dolomite.
TYPE LOCATION: Big Horn County, Montana; unsurveyed; 425 feet east and 300 feet south of the point where the Lodgegrass Creek Canyon trail crosses the log fence at the Wyoming-Montana State line in the Big Horn Mountains.
RANGE IN CHARACTERISTICS: Mean annual temperature is 42 to 44 degrees F. Depth to shattered limestone and dolomite is 20 to 40 inches. Rock fragments of gravel to stone size make up from 0 to 15 percent of the A and upper B horizon and from 15 to 20 percent of the lower B and the C horizons. Hue is 10YR or 2.5Y. The mollic epipedon ranges from 7 to 15 inches thick.
The A horizon has value of 5 or 4 dry, and chroma of 3 or 2. It has moderate or strong platy structure.
The Bt horizon has value of 5 or 4 dry, 4 or 3 moist, and chroma of 3 or 4. It is clay loam or silty clay loam and has 27 to 35 percent clay and has a few pebbles in the lower part in some pedons.
The C horizon has value of 6 or 5 dry, 5 or 4 moist and chroma or 3 or 4. It is gravelly or very gravelly. This horizon has weak effervescence immediately above the bedrock in some pedons. It is neutral or slightly alkaline.
COMPETING SERIES: These are the Bear Basin, Hourglass, McIntyre, Mult, Paintrock, Sponsor, Swede, Trapper, and Wildcow series. Bear Basin, Hourglass, Sponsor, Swede, and Wildcow soils are more than 40 inches deep. McIntyre soils have albic horizons, and are strongly acid. Mult soils have an argillic horizon that extends to the lithic contact. Paintrock soils have Cca horizons. Trapper soils have albic horizons and prominent Cca horizons.
GEOGRAPHIC SETTING: Quietus soils are on moderately steep and steep hills and valley sides in the Big Horn Mountains at elevations of 7,000 to 9,000 feet. The underlying limestone is mainly the lower members of the Madison formation of the Mississippian Age. The soils formed in residuum and colluvium from hard limestone. Mean annual precipitation is 20 to 34 inches. Mean annual temperature is 38 to 42 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Benteen soils and the Hanson, Latang, Mayflower and Tropal soils. Hanson soils lack an argillic horizon, are skeletal and have a calcic horizon. Mayflower soils have a thick mollic epipedon and lack an A2 horizon. Tropal soils have a calcic horizon and have a lithic contact with hard limestone at depths of less than 20 inches.
DRAINAGE AND PERMEABILITY: Well-drained; moderate permeability.
USE AND VEGETATION: Timber production only. Mixed stands of Englemann spruce and alpine fir. Understory of huckleberry, Oregongrape and lupine.
DISTRIBUTION AND EXTENT: Southeastern part of the Big Horn Mountains in Montana. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Big Horn County (Big Horn Area), Montana, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone from 2 to 9 inches ( A, and Bt1 horizons)
Argillic horizon - zone from 5 to 18 inches (Bt1, Bt2, and Bt3 horizons)
Moisture regime - udic