LOCATION SPEARHEAD               WY+ID MT

Established Series
Rev. PSD/KLS
07/2022

SPEARHEAD SERIES

The Spearhead series consists of deep, well drained soils that formed in colluvium from calcareous sedimentary or metamorphic rocks. Spearhead soils are on steep to extremely steep mountain sides. The average annual precipitation is about 890 mm and the mean annual air temperature is about 0 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Calcic Pachic Haplocryolls

TYPICAL PEDON: Spearhead very gravelly loam-rangeland. (Colors are for dry soil unless otherwise stated.)

Oi--0 to 3 cm; grass litter.

A--3 to 94 cm; brown (10YR 4/3) very gravelly loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure parting to moderate fine granular; slightly hard, very friable, slightly sticky and slightly plastic; 30 percent pebbles and 10 percent cobbles; slightly alkaline (pH 7.6); gradual wavy boundary. (40 to 100 cm thick)

Bk--94 to 155 cm; very pale brown (10YR 7/3) extremely cobbly sandy loam, brown (10YR 5/3) moist; weak fine granular structure; slightly hard, very friable, slightly sticky; 45 percent pebbles, 30 percent cobbles; strongly calcareous; moderately alkaline (pH 8.2).

TYPE LOCATION: Teton County, Wyoming; in an unsectionized area.

RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--40 to 100 cm
Depth to calcareous material--40 to 100 cm
Mean annual soil temperature--0 to 2 degrees C
Mean summer temperature--4 to 7 degrees C

Particle-size control section:
Texture--loam or sandy loam
Clay content--less than 18 percent
Rock Fragment content--20 to 45 percent gravel and 15 to 30 percent cobbles

A horizon
Hue--10YR or 7.5YR
Value--4 or 5 dry and 2 or 3 moist
Chroma--2 or 3
Texture--loam
Rock fragment content--35 to 65 percent gravel

C or Bk horizon
Hue--10YR or 7.5YR
Value--5 through 7 dry and 4 through 6 moist
Chroma--2 or 3
Calcium carbonate equivalent--5 to 14 percent
Reaction--pH 7.8 to 8.4

COMPETING SERIES: These are the Behanin, Blanca, Caballo, Campone, Croesus, Dateman, Ence, Gateview, Hapgood, Harcany, Hobacker, Lolan, Marcetta, Nagitsy, Nazaton, Nevtah, Poleline, Prong, and Snag series. Behanin, Blanca, Campone, Ence, Gateview, Hapgood, Harcany, Lolan, Marcetta, Nazaton, Poleline and Snag soils are noncalcareous. Caballo, Croesus, Dateman, Nagitsy, Nevtah, and Prong soils have bedrock at a depth of less than 100 cm. Hobacker soils have extremely gravelly loamy sand or sand horizon within a depth of 100 cm.

GEOGRAPHIC SETTING:
Landform--mountain side slopes
Elevation--2125 to 3350 meters
Slope--0 to 70 percent
Parent Material--colluvium weathered from calcareous sedimentary and metamorphic rocks
Mean annual precipitation--760 to 1100 mm
Mean annual temperature--minus 1 to 1 degrees C
Frost-free season--less than 60 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability

USE AND VEGETATION: These soils are used for recreation and wildlife habitat. Native vegetation is widely spaced Englemann spruce, alpine fir, wild geranium, lupine, parsley, and slender wheatgrass.

DISTRIBUTION AND EXTENT: Spearhead are moderately extensive in the mountains of northwestern Wyoming, central Montana, and southeast Idaho; MLRAs 12, 13 and 43B

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

SERIES ESTABLISHED: Teton County, Wyoming, Grand Teton National Park Area; 1976

REMARKS: Converted to metric, updated formatting, and O horizons were updated to start at zero; 7/2022

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National Cooperative Soil Survey
U.S.A.