LOCATION ANGOSTURA          NM+CO
Established Series
Rev. GWA/LWH/LN/JWB
10/2007

ANGOSTURA SERIES


The Angostura series consists of very deep, well drained, moderately permeable soils that formed in material weathered from mixed rocks. Angostura soils are on mountain slopes. Slopes range from 5 to 80 percent. The mean annual precipitation is about 27 inches and the mean annual temperature is about 35 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Typic Glossocryalfs

TYPICAL PEDON: Angostura stony loam, forested. (Colors are for dry soil unless otherwise noted.)

0i--0 to 2 inches; decayed and undecayed forest litter. (0 to 2 inches thick)

E--2 to 9 inches; light brownish gray (10YR 6/2) stony loam, dark grayish brown (10YR 4/2) moist; weak coarse subangular blocky structure parting to weak fine granular; soft, friable, slightly sticky and slightly plastic; many fine, medium and coarse roots; common very fine tubular pores; 5 percent gravel and 25 percent stones; moderately acid; clear smooth boundary. (6 to 12 inches thick)

Bt/E--9 to 24 inches; 70 percent Bt1 material: light yellowish brown (10YR 6/4) stony sandy clay loam, brown (7.5YR 4/4) moist; slightly hard, moderately sticky and friable, plastic; few thin clay films on sand grains and as bridges between sand grains; 30 percent E material: light brownish gray (10YR 6/2) stony loam, brown (10YR 4/3) moist; soft, friable slightly sticky and slightly plastic; weak coarse subangular blocky structure parting to weak fine granular; many fine, medium and coarse roots; common very fine tubular pores; 5 percent gravel, 5 percent cobbles, and 15 percent stones; moderately acid; gradual smooth boundary. (5 to 16 inches thick)

Bt1--24 to 45 inches; light yellowish brown (10YR 6/4) very stony sandy clay loam, brown (7.5YR 4/4) moist; moderate fine prismatic structure parting to weak medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common fine, medium coarse roots; common very fine tubular pores; few thin clay films on faces of peds; 5 percent gravel, 5 percent cobbles, and 30 percent stones; moderately acid; gradual wavy boundary. (11 to 30 inches thick)

Bt2--45 to 62 inches; light yellowish brown (10YR 6/4) very stony sandy clay loam, brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common very fine tubular pores; few thin clay films lining pores; 5 percent gravel, 5 percent cobbles, and 50 percent stones; moderately acid.

TYPE LOCATION: Colfax County, New Mexico; about 3 miles west of Black Lake; 2,000 feet south and 510 feet east of the NW corner of Sec. 26, T. 24 N., R. 15 E. 105 degrees, 19 minutes, 34 seconds west longitude; 36 degrees, 17 minutes, 10 seconds north latitude.

RANGE IN CHARACTERISTICS: Depths are from the mineral soil surface.
Soil Moisture: The SMCS is moist in at least some part all year.
Soil Temperature: 32 to 40 degrees F.
Depth to glossic horizon: 6 to 12 inches.
Mean summer temperature: 42 to 46 degrees F.
Depth to base of the Bt horizon: 44 inches or more.

A horizons: if present
Hue : 7.5YR or 10YR
Value: 4 to 6, 3 or 4 moist
Chroma: 2 or 3

E horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7, 4 or 5 moist
Chroma: 2 to 4
Texture: very cobbly sandy loam, stony loam, very stony loam, very stony sandy clay loam,
Rock fragments total: 20 to 60 percent

Bt horizons:
Hue: 7.5YR or 10YR
Value: 5 or 6, 4 or 5 moist
Texture: very stony sandy clay loam, very cobbly sandy clay loam, extremely stony sandy clay loam, extremely stony clay loam or extremely cobbly clay loam, very cobbly clay loam, very cobbly loam.
Clay Content: 20 to 30 percent clay.
Rock fragments total: 35 to 80 percent; dominantly cobbles and stones.
Reaction: moderately acid or slightly acid

Some pedons have a C horizon

COMPETING SERIES: These are the Duchesne(UT) series.
Duchesne soils: have a very strongly acid or strongly acid A horizon and have peak periods of precipitation from fall to spring.

GEOGRAPHIC SETTING:
Landform: mountain slopes
Elevation: 9,000 to 12,000 feet
Slopes: 5 to 80 percent
Parent material: material weathered from mixed rocks
Mean annual temperature: 32 to 40 degrees F, and a summer temperature of 40 to 44 degrees F.
Mean annual precipitation is 25 to 37 inches. Frost-free period: less than 70 days in New Mexico and is less than 90 days in Colorado

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bundo, Cypher, Etoe, Etown, Tolby and Wellsville soils. Bundo, Cypher, Etoe and Etown soils lack a cryic temperature regime. Tolby soils lack an argillic horizon. Wellsville soils have a mollic epipedon.

DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; moderate permeability.

USE AND VEGETATION: Woodland, wildlife habitat, recreation and watershed. Vegetation is Engelmann's spruce, subalpine fir, aspen, Douglas-fir, white fir, tall oatgrass, pine dropseed, kinnickinnick and whortleberry.

DISTRIBUTION AND EXTENT: Rocky Mountains of New Mexico and Colorado; LRR E, MLRA 48A; This series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Colfax County, New Mexico, 1974.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 2 to 9 inches (E horizon)
Albic horizon: the zone from 2 to 9 inches (E horizon)
Glossic horizon: the zone from 9 to 24 inches (Bt/E horizon).
Argillic horizon: The zone 24 to 64 inches and 70 percent of 9 to 24 inch layer. (Bt and 70 percent of the B/E horizons)

Remarks:
Additional Notes: Further study is needed to determine if the E part of the Bt/E horizon typically fails the glossic requirement because of moist color.

Taxonomic Version: Eighth Edition, 1998


National Cooperative Soil Survey
U.S.A.