LOCATION TRAILRIDGE COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, micaceous, shallow Typic Humicryepts
TYPICAL PEDON: Trailridge extremely gravelly sandy loam - on a south-facing, convex, 22 percent slope in tundra at an elevation of 11,500 feet. (Colors are for dry soil unless otherwise noted.) When described on August 7, 1996 the soil was moist throughout.
The surface is covered with 10 percent stones.
A1--0 to 6 inches; dark grayish brown (10YR 4/2) extremely gravelly sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots and common medium roots; 55 percent gravel and 10 percent cobbles; very strongly acid (pH 5.0); abrupt smooth boundary.
A2--6 to 11 inches; very dark grayish brown (10YR 3/2) extremely gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots and common medium roots; 55 percent gravel and 10 percent cobbles; very strongly acid (pH 4.8); abrupt smooth boundary. (combined thickness of the A horizons is 6 to 11 inches)
Bw--11 to 19 inches; yellowish brown (10YR 5/4) extremely gravelly coarse sandy loam, dark yellowish brown (10YR 4/4) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots and few fine roots; 60 percent gravel and 15 percent cobbles; very strongly acid (4.8); clear smooth boundary. (4 to 8 inches thick)
Cr--19 to 29 inches; soft weathered schist. (5 to 10 inches thick)
TYPE LOCATION: Larimer County, Colorado; about 1.1 miles east of Alpine visitors center; located on Marmot Point in Rocky Mountain National Park.; Trail Ridge USGS quad; lat. 40 degrees 26 minutes 40 seconds N. and long. 105 degrees 44 minutes 14 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture regime: udic moisture regime
Mean annual soil temperature: 32 to 36 degrees F.
Mean summer soil temperature: 43 to 47 degrees F.
Surface rock fragments: 5 to 35 percent, dominantly gravel
Depth to paralithic contact: 10 to 20 inches to schist, gneiss, granite
Thickness of the umbric epipedon: 7 to 20 inches
Base saturation: 30 to 50 percent
Particle-size control section (weighted average):
Clay content: 8 to 18 percent
Sand content: 45 to 70 percent
Mica content: 40 to 70 percent (by grain count)
A horizons:
Hue: 7.5YR or 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 to 3
Clay content: 8 to 18 percent
Rock fragments: 60 to 70 percent
Reaction: very strongly acid or strongly acid
Bw horizon:
Hue: 7.5YR to 10YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 3 to 6
Clay content: 8 to 18 percent
Texture: extremely gravelly sandy loam, extremely gravelly coarse sandy loam
Rock fragments: 60 to 80 percent, dominantly gravel
Reaction: very strongly acid to moderately acid
COMPETING SERIES: There are presently no other series in this family. The
Archrock (CO),
Goldcord (AK),
Mummy (CO), and
Teewinot (WY) series are similar.
Archrock soils have a paralithic contact at depths of 20 to 40 inches.
Goldcord and Teewinot soils have a lithic contact at depths of less than 20 inches.
Mummy soils are very deep.
GEOGRAPHIC SETTING:
Parent material: Slope alluvium and residuum derived from schist, gneiss, and granitic rocks
Landform: mountains
Slopes: 10 to 60 percent
Elevation: 10,400 to 12,500 feet
Mean annual air temperature: 34 to 38 degrees F.
Mean annual precipitation: 30 to 40 inches.
Wettest months: March and April.
Driest months: September and October.
Frost-free period: 10 to 30 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Archrock, Hiamovi, Fallriver, and Mummy series. Archrock soils have a paralithic contact at depths of 20 to 40 inches and are on lesser sloping areas. Hiamovi soils lack an umbric epipedon and are on shoulders. Fallriver and Mummy soils are greater than 60 inches to bedrock and are on lower adjacent backslopes.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained, rapid to very rapid runoff, moderately rapid permeability.
USE AND VEGETATION: These soils are used for recreation and wildlife habitat. Native vegetation is alpine avens, alpine bluegrass, rock sedge, arctic sagebrush and alpine willow. Areas of Krummholz have scattered Engelmann's spruce and subalpine fir.
DISTRIBUTION AND EXTENT: Mountain tundra in north central Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Larimer County, Colorado, 1999, Rocky Mountain National Park soil survey area. The name was taken from the Trail Ridge Road.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon: The zone from 0 to 11 inches. (A1 and A2 horizons)
Cambic horizon: The zone from 11 to 19 inches. (Bw horizon)
Particle-size control section: The zone from 10 to 19 inches. (part of the A2 and the Bw horizon)
Paralithic contact: At 19 inches. (upper boundary of the Cr layer)
Keys to Soil Taxonomy: Series classified according to Eighth Edition, 1998.
ADDITIONAL DATA:
The mineralogy class was changed from paramicaceous to micaceous in 07/2010 by the National Soil Survey Center on request of the responsible MLRA regional office. The change was necessary based on the eleventh edition of the Keys to Soil Taxonomy, 2010.