LOCATION MORSCOUR CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, shallow Xeric Haplocryolls
TYPICAL PEDON: Morscour extremely gravelly sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 35 percent gravel, 10 percent cobbles, 5 percent stones, and 5 percent boulders.
A1--0 to 2 inches; grayish brown (10YR 5/2) extremely gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine interstitial and tubular pores; 50 percent gravel, 5 percent cobbles, and 5 percent stones; slightly acid; clear wavy boundary. (2 to 4 inches thick)
A2--2 to 7 inches; brown (10YR 5/3) very gravelly sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and common fine roots; common very fine interstitial and tubular pores; 50 percent gravel and 5 percent cobbles; 20 percent paragravel; slightly acid; clear irregular boundary. (2 to 6 inches thick)
Cr--7 to 14 inches; weathered fractured tuff.
R--14 inches; hard tuff.
TYPE LOCATION: Alpine County, California; on the Toiyabe National Forest about 1.7 miles southeast of Red Lake; approximately 550 feet north and 2,350 feet east of the southwest corner of section 25, T. 10 N., R. 18 E.; USGS Carson Pass 7.5 minute topographic quadrangle; 38 degrees 40 minutes 38.5 seconds north latitude and 119 degrees 57 minutes 13.1 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during fall, winter, and spring; dry from July through September for 60 to 80 consecutive days in the four months following the summer solstice; Typic xeric moisture regime.
Mean annual soil temperature - 44 to 47 degrees F.
Mean summer soil temperature - 54 to 59 degrees F.
Mollic epipedon thickness - 4 to 10 inches.
Depth to bedrock - 4 to 10 inches to a paralithic contact. The paralithic materials below the contact are weathered tuff or tuff-breccia.
Sodium fluoride pH - 8.5 to 9.5.
Particle-size control section - Clay content: Averages 12 to 18 percent; Rock fragments: Averages 35 to 60 percent, mainly gravel. Lithology of fragments are volcanic rocks such as tuff and granitic rocks such as granodiorite.
A horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Clay content: 12 to 18 percent.
Rock fragments: 35 to 60 percent.
Pararock fragments: 0 to 25 percent paragravel.
Organic matter content: 2 to 4 percent.
Reaction: Moderately acid to neutral.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Morscour soils are on mountains. They typically occur on backslope positions which have been scoured by glacial ice. They formed mainly in residuum derived from tuff, tuff-breccia, and andesite. Minor amounts of till and colluvium derived from mixed rocks occurs as surface deposits. Slopes are 8 to 30 percent. Elevations range from 8,000 to 9,000 feet. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 35 to 55 inches, mean annual temperature is 35 to 40 degrees F., and the frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Florand, Lostridge, and Stumpatil soils. Florand soils are deep to paralithic contacts and have umbric epipedons and cambic horizons. Lostridge soils are moderately deep to paralithic contacts and have umbric epipedons and cambic horizons. Stumpatil soils are very deep and have umbric epipedons and argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderately rapid permeability (high saturated hydraulic conductivity).
USE AND VEGETATION: Morscour soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly mountain big sagebrush, snowberry, mule'sear wyethia, and mountain brome.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 260 acres of the series mapped to date. MLRA 22A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Alpine County (Toiyabe National Forest Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 7 inches (A1 and A2 horizons).
Paralithic contact - The boundary at 7 inches to underlying soft bedrock (Cr layer).
Particle-size control section - The zone from the soil surface to 7 inches (A1 and A2 horizons).
The revision of October 2003 updated the taxonomic class from Loamy-skeletal, isotic, shallow Xeric Haplocryolls. The isotic mineralogy class was based solely on the field determined values for sodium fluoride pH. Laboratory data on 15 bar water to clay ratio does not exist to verify the isotic mineralogy class.