LOCATION TEPECREEK               MT

Established Series
Rev. PEM-JAL-KLS
09/2022

TEPECREEK SERIES

The Tepecreek series consists of moderately deep, well drained soils that formed in colluvium, slope alluvium or residuum derived from granite bedrock. These soils are on escarpments, ridges and sideslopes of mountains. Slopes are 8 to 60 percent. Mean annual precipitation is about 560 mm, and mean annual air temperature is about 3 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Haplocryalfs

TYPICAL PEDON: Tepecreek very gravelly sandy clay loam, very bouldery, forested (colors are for dry soil unless otherwise noted).

Oi--0 to 3 cm; partially decomposed needles, twigs, and leaves. (1 to 8 cm thick)

A--3 to 8 cm; grayish brown (10YR 5/2) very gravelly sandy clay loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine and fine and few medium pores; 35 percent pebbles; slightly acid (pH 6.3); clear smooth boundary. (5 to 10 cm thick)

E--8 to 23 cm; brown (10YR 5/3) very gravelly sandy clay loam, dark grayish brown (10YR 4/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine and fine and few medium pores; 40 percent pebbles; slightly acid (pH 6.2); clear smooth boundary. (8 to 20 cm thick)

Bt--23 to 48 cm; yellowish brown (10YR 5/4) very gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; many very fine and few fine and medium roots; many very fine and few fine interstitial and tubular pores; many faint clay films bridging sand grains; 40 percent pebbles; slightly acid (pH 6.1); clear wavy boundary. (13 to 35 cm thick)

BC--48 to 91 cm; olive brown (2.5Y 4/4) very gravelly sandy loam, very dark grayish brown (2.5Y 3/2) moist; weak very fine and fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many very fine and few fine roots; many very fine and few fine interstitial and tubular pores; 55 percent pebbles; neutral (pH 6.6); clear wavy boundary. (28 to 70 cm thick)

Cr--91 to 134 cm; light olive brown (2.5Y 5/4) decomposed granite bedrock (grus) that crushes to very gravelly loamy coarse sand; slightly acid (pH 6.4); gradual wavy boundary. (13 to 50 cm thick)

R--134 cm; hard granite bedrock.

TYPE LOCATION: Jefferson County, Montana; about 410 meters south and 450 meters west of the NE corner of sec. 32, T. 9 N., R. 2 W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 6 degrees C
Moisture control section--10 to 30 cm
Depth to argillic horizon--13 to 30 cm
Depth to Cr horizon--50 to 100 cm
Depth to bedrock--100 to 150 cm
Surface stones or boulders--0 to 3 percent

A horizon
Hue--10YR or 2.5Y
Value--4 or 5 dry; 3 or 4 moist
Chroma--2 or 3
Texture--coarse sandy loam, sandy loam, or sandy clay loam
Clay content--10 to 25 percent
Rock fragment content--5 to 50 percent pebbles
Reaction--pH 6.1 to 7.3

E horizon
Hue--10YR or 2.5Y
Value--5 or 6 dry; 4 or 5 moist
Chroma--2 or 3
Texture--coarse sandy loam, sandy loam, or sandy clay loam
Clay content--10 to 25 percent
Rock fragment content--5 to 50 percent pebbles, mostly less than 7 mm in diameter
Reaction--pH 6.1 to 7.3

Bt horizon
Hue--10YR or 2.5Y
Value--5 or 6 dry; 4 or 5 moist
Chroma--2, 3, or 4
Clay content--20 to 30 percent
Rock fragment content--35 to 60 percent pebbles, mostly less than 7 mm in diameter
Reaction--pH 6.1 to 7.3

BC horizon
Hue--10YR or 2.5Y
Value--4, 5, or 6 dry; 3, 4, or 5 moist
Chroma--2, 3, or 4
Texture--coarse sandy loam or sandy loam
Clay content--10 to 18 percent
Rock fragment content--35 to 60 percent pebbles, mostly less than 10 mm in diameter
Reaction--pH 6.1 to 7.3

COMPETING SERIES:
Cadotte (MT) - has a discontinuity of sandy-skeketal material above a depth of 100 cm.
Cloud Peak (WY) - 50 to 100 cm deep to a lithic contact; has a horizon of secondary carbonate accumulation.
Cundiyo (NM) - has a sandy-skeletal discontinuity above a depth of 150 cm.
Guffy (CO) - does not have a lithic contact above a depth of 150 cm.
Hyattville (WY) - 50 to 100 cm deep to a lithic contact; has mixed A/B horizons; has horizons of secondary carbonate accumulation.
Kebler (CO) - 50 to 100 cm deep at a lithic contact; rock fragments are mainly stone size. Kimpton (MT) - has a horizon of secondary carbonate accumulation above a depth of 50 to 100 cm; does not have a paralithic contact above the bedrock.
Lake Creek (WY) - 50 to 100 cm deep at a lithic contact; has rock fragments predominantly larger than 25 cm.
Lakehelen (WY) - 50 to 100 cm deep to a lithic contact; has hue of 7.5YR and redder in the argillic horizon; is slightly to moderately acid in the argillic horizon.
Losee (UT) - is calcareous throughout the particle-size control section.
MacFarlane (CO) - is extremely stony throughout; the less than 2 mm fraction is coarse-loamy.

GEOGRAPHIC SETTING:
Landform--escarpments, ridges and sideslopes of mountains
Elevation--1700 to 2450 meters
Slope--8 to 60 percent
Parent material--colluvium, slope alluvium or residuum derived from granite bedrock
Climate--long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation--380 to 760 mm
Mean annual air temperature--2 to 4 degrees C
Frost-free period--30 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Well drained; moderate permeability in the argillic horizon and moderately rapid below

USE AND VEGETATION: Tepecreek soils are primarily used for timber production and wildlife habitat. The potential native vegetation is mainly Douglas fir, lodgepole pine, pinegrass, russet buffaloberry, common snowberry, Kinnikinnick, raceme pussytoes, white spiraea, mahonia, and grouse whortleberry.

DISTRIBUTION AND EXTENT: Tepecreek soils are moderately extensive in southwestern Montana; MLRA 43B and 44B

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

SERIES ESTABLISHED: Jefferson County, Montana, 1998.

REMARKS: Soil interpretation record: MT3086, MT3087, MT3088.
Diagnostic horizons and features recognized in this pedon are:
Layer of partially decomposed needles, twigs, and leaves--0 to 3 cm (Oi horizon)
Ochric epipedon--3 to 23 cm (A and E horizons)
Argillic horizon--23 to 48 cm (Bt horizon)
Paralithic contact--91 to 134 cm to decomposed granite (Cr horizon)
Lithic contact--134 cm to hard granite bedrock (R horizon)
Particle-size control section--23 to 48 cm (Bt horizon)

Converted to metric, updated formatting, and O horizons were updated to start at zero. Competing series section was not updated. 9/2022

Tepecreek soils have a cryic temperature regime and an ustic soil moisture regime.

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National Cooperative Soil Survey
U.S.A.