LOCATION CARRACAS COEstablished Series
TAXONOMIC CLASS: Clayey, mixed, superactive, frigid, shallow Typic Haplustepts
TYPICAL PEDON: Carracas clay loam, on a west facing, simple, 12 percent slope in ponderosa pine woodland at an elevation of 7300 feet. (Colors are for dry soil unless otherwise noted.) When described on June 21, 1984 the soil was moist from 0 to 15 inches.
A--0 to 3 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak thick platy structure parting to moderate medium granular structure; hard, firm, moderately sticky, moderately plastic; common very fine roots throughout; common fine and very fine tubular pores; 2 percent cobbles and 5 percent parachanners; slightly effervescent; 3 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear smooth boundary. (2 to 5 inches thick)
Bw1--3 to 8 inches; grayish brown (10YR 5/2) clay, brown (10YR 4/3) moist; weak medium angular blocky structure; very hard, very firm, very sticky, very plastic; common fine and very fine roots; common very fine tubular pores; 10 percent parachanners; strongly effervescent; 8 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear wavy boundary. (3 to 12 inches thick)
Bw2--8 to 15 inches; brown (10YR 5/3) clay, brown (10YR 4/3) moist; weak medium angular blocky structure; very hard, very firm, very sticky, very plastic; common fine and very fine roots; common very fine tubular pores; 14 percent parachanners; strongly effervescent; 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear wavy boundary. (0 to 8 inches thick)
Cr--15 to 25 inches; weakly cemented shale bedrock, moderately alkaline.
TYPE LOCATION: Archuleta County, Colorado; about 12 miles west of Pagosa Springs; located about 950 feet east and 3800 feet north of the southwest corner of sec. 4, T. 35 N., R. 3 W.; Lonetree Canyon USGS quad; lat. 37 degrees 14 minutes 22 seconds N. and long. 107 degrees 13 minutes 0 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture: Ustic moisture regime, typic subclass
Mean annual soil temperature: 44 to 47 degrees F.
Mean summer soil temperature: 60 to 63 degrees F.
Depth to paralithic contact: 10 to 20 inches to shale
Depth to calcium carbonate: 0 to 5 inches
Thickness of cambic horizon: 7 to 17 inches
Particle-size control section (weighted average):
Clay content: 35 to 45 percent
Rock fragments: 0 to 2 percent
A horizon:
Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 1 to 3, dry or moist
Clay content: 40 to 45 percent
Rock fragments: 0 to 5 percent
Pararock fragments: 0 to 10 percent
Calcium carbonate equivalent: 1 to 5 percent
Reaction: 7.4 to 8.4
Bw1 horizon:
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 1 to 3
Texture: clay, clay loam, silty clay loam
Clay content: 35 to 45 percent
Pararock fragments: 0 to 15 percent
Calcium carbonate equivalent: 5 to 15 percent
Bw2 horizon:
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 1 to 3
Texture: clay, clay loam, silty clay loam, parachannery clay loam
Clay content: 35 to 45 percent
Pararock fragments: 5 to 35 percent
Calcium carbonate equivalent: 5 to 15 percent
Cr horizon:
Shale bedrock
COMPETING SERIES: There are no competing series. A similar soil is the Echolake series, which is moderately deep to shale.
GEOGRAPHIC SETTING: Carracas soils.
Parent material: slope alluvium derived from shale.
Landform: hills.
Slopes: 3 to 60 percent
Elevation: 7000 to 8300 feet
Mean annual temperature: 42 to 45 degrees F.
Mean annual precipitation: 18 to 22 inches.
Precipitation pattern:
Wettest months: May and June are the driest months, July and August are the wettest months.
Frost-free period: 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Echolake and Herm series. The Echolake soils are moderately deep and on hills. The Herm soils are very deep and on footslopes of hills.
DRAINAGE AND PERMEABILITY: Well drained, high runoff, slow permeability.
USE AND VEGETATION: Major use is for livestock grazing, timber production, and wildlife habitat. Native vegetation is ponderosa pine, Rocky mountain juniper, Gambels oak, antelope bitterbrush, big sagebrush, mountain mahogany, western wheatgrass, Arizona fescue, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Southwestern Colorado. LRR D, MLRA 36. This series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Lakewood, Colorado.
SERIES ESTABLISHED: La Plata County (Piedra Area), Colorado, 1974. The current type location is in the Archuleta soil survey area. The name is from a small community in Archuleta county.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 3 inches. (A horizon)
Cambic horizon: The zone from 3 to 15 inches. (Bw1 and Bw2 horizons)
Particle-size control section: The zone from 10 to 15 inches. (part of the Bw2 horizon)
Paralithic contact: The contact with shale at 15 inches. (Cr layer)
Series control section: the zone from 0 to 25 inches (all horizons and upper 10 inches of the paralithic layer)
The 05/2005 revision moves the typical pedon from La Plata County to Archuleta County, and changes the classification from loamy, mixed, superactive, nonacid, shallow Typic Ustorthents. This series was used in an older soil survey of the adjoining Piedra area that is being updated. The original Carracas series is not used in the updated survey.
The 6/2006 revision changes the mineralogy from smectitic to mixed.
Taxonomic Version: Ninth Edition, Keys to Soil Taxonomy, 2003.