LOCATION YMARK                   MT

Established Series
Rev. PEM-JAL-KLS
05/2023

YMARK SERIES

The Ymark series consists of well drained soils that are deep to grus and hard granite bedrock. These soils formed in colluvium derived from hard fine grained and coarse grained igneous rock deposited over hard granite bedrock. They are on alluvial fans, ridges and sideslopes of hills and mountains. Slopes are 15 to 60 percent. Mean annual precipitation is about 460 mm, and mean annual air temperature is about 4 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustalfs

TYPICAL PEDON: Ymark very cobbly sandy loam, very bouldery, dry, in forest (Colors are for dry soil unless otherwise noted).

Oe--0 to 3 cm; partially decomposed needles, twigs and leaves.

A--3 to 18 cm; dark grayish brown (10YR 4/2) very cobbly sandy loam, very dark gray (10YR 3/1) moist; weak medium and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine and medium roots; many very fine and few fine pores; 15 percent cobbles and 25 percent gravel; neutral (pH 7.1); clear smooth boundary. (10 to 15 cm thick)

Bt1--18 to 28 cm; brown (10YR 5/3) very cobbly sandy clay loam, brown (10YR 4/3) moist; weak medium and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine and medium roots; many very fine and few fine pores; few faint clay films on faces of peds and bridging sand grains; 15 percent cobbles and 25 percent gravel; neutral (pH 6.8); clear smooth boundary.

Bt2--28 to 58 cm; yellowish brown (10YR 5/4) very cobbly sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak medium prismatic structure parting to moderate medium and fine subangular blocky; slightly hard, friable, moderately sticky and slightly plastic; many very fine and few fine, medium and coarse roots; many very fine and few fine tubular and interstitial pores; many faint clay films on faces of peds and bridging sand grains; 30 percent cobbles and 20 percent gravel; slightly acid (pH 6.2); clear wavy boundary.

Bt3--58 to 94 cm; yellowish brown (10YR 5/4) very cobbly coarse sandy clay loam, brown (10YR 4/3) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; many very fine and few fine tubular and interstitial pores; many faint clay films bridging sand grains; 30 percent cobbles and 20 percent gravel; neutral (pH 6.8); clear wavy boundary. (Combined thickness of Bt horizons - 50 to 90 cm).

BC--94 to 114 cm; yellowish brown (10YR 5/6) very cobbly coarse sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium and fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and few fine and medium roots; many very fine and few fine tubular and interstitial pores; 10 percent stones, 25 percent cobbles and 20 percent gravel; neutral (pH 6.9); clear wavy boundary. (13 to 38 cm thick)

Cr--114 to 150 cm; olive (5Y 5/3) decomposed granite bedrock (grus) that crushes to very gravelly loamy coarse sand; neutral (pH 7.0). (8 to 38 cm thick)

R--150 cm; hard granite bedrock.

TYPE LOCATION: Jefferson County, Montana; about 150 meters north and 105 meters east of the SW corner of sec. 3, T. 8 N., R. 4 W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 7 degrees C
Soil moisture control section--10 to 30 cm
Depth to paralithic contact--100 to 147 cm
Depth to lithic contact--109 to 150 cm
Surface stones or boulders--0 to 3 percent

A horizon
Hue--10YR or 2.5Y
Value--4 or 5 dry; 2 or 3 moist
Chroma--1, 2 or 3
Texture--coarse sandy loam, sandy loam or sandy clay loam
Clay content--10 to 25 percent
Rock fragment content--20 to 50 percent total; 0 to 20 percent stones and cobbles, 15 to 35 percent gravel
Reaction--pH 6.6 to 7.3

Bt horizons
Hue--10YR or 2.5Y
Value--5 or 6 dry; 4 or 5 moist
Chroma--2, 3 or 4
Texture--coarse sandy loam, sandy clay loam or clay loam
Clay content--18 to 30 percent
Rock fragment content--35 to 60 percent total; 5 to 30 percent stones and cobbles, 20 to 40 percent gravel
Base saturation--60 to 100 percent
Reaction--pH 6.1 to 7.3

BC horizon
Hue--10YR or 2.5Y
Value--5 or 6 dry; 4 or 5 moist
Chroma--2, 3, 4 or 6
Texture--loamy sand, coarse sandy loam or sandy loam
Clay content--10 to 20 percent
Rock fragment content--35 to 70 percent total; 5 to 35 percent stones and cobbles, 20 to 45 percent gravel
Reaction--pH 6.1 to 7.3

COMPETING SERIES:
Amcec (NM) - has horizons of secondary carbonate acumulation; does not have a lithic contact above 150 cm.
Macmeal (MT) - does not have a lithic contact above 150 cm.
Mocmont (MT) - does not have a lithic contact; has a glossic horizon.
Sheek (CO) - does not have a lithic contact above 150 cm; hues are mainly 7.5YR in the argillic horizon and below.
Vision (MT) - does not have a lithic contact.
Yourame (MT) - has a horizon of calcium carbonate accumulation; does not have a lithic contact above 150 cm.
Yreka (MT) - does not have a lithic contact above 150 cm.

GEOGRAPHIC SETTING:
Landform--alluvial fans, ridges and sideslopes of hills and mountains
Elevation--1350 to 1825 meters
Slope--15 to 60 percent
Parent material--colluvium derived from hard fine grained and coarse grained igneous rock deposited over hard granite bedrock
Climate--long, cold winters; moist springs; warm summers
Mean annual precipitation--380 to 480 mm
Mean annual air temperature--2 to 6 degrees C
Frost-free period--70 to 105 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.

USE AND VEGETATION: Ymark soils are primarily used for timber production, wildlife habitat and watershed. The potential native vegetation is mainly Douglas-fir, ponderosa pine, common snowberry, pinegrass, heartleaf arnica, white spiraea, russet buffaloberry, currant, rough fescue, Idaho fescue, and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: Ymark soils are of small extent in southwestern Montana; MLRA 43B.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Jefferson County, Montana, 1998.

REMARKS: Soil interpretation record: MT3025, MT3026.
Diagnostic horizons and features recognized in this pedon are:
Dark colored layer--3 to 18 cm (A horizon)
Argillic horizon--18 to 94 cm (Bt1, Bt2 and Bt3 horizons)
Paralithic contact--114 to 150 cm to layer of decomposed granite (grus) (Cr horizon)
Lithic contact--150 cm to hard granite bedrock (R horizon)
Particle-size control section--18 to 68 cm (Bt1, Bt2 horizons and part of the Bt3 horizon)

Ymark soils have a frigid temperature regime and an ustic soil moisture regime.

Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 05/2023

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National Cooperative Soil Survey
U.S.A.