LOCATION THIRST CA
Established Series
DCE/RLR/ET
01/2023
THIRST SERIES
The Thirst series consists of shallow well drained soils that formed in materials derived from volcanic rock such as andesite or dacite. Thirst soils are on hills and mountain sideslopes and have slopes of 9 to 75 percent. The mean annual precipitation is about 260 millimeters (about 10 inches) and the mean annual temperature is about 16.5 degrees C. (62 degrees F.).
TAXONOMIC CLASS: Clayey-skeletal, smectitic, thermic Lithic Haploxeralfs
TYPICAL PEDON: Very cobbly silt loam; on a 9 percent slope facing south under a cover of slender oats, stipa, clover, lupine and red brome at 1730 feet elevation. (Colors are for dry soil, unless otherwise stated) When described on 6/8/82 the soil was dry throughout.
A--0 to 8 centimeters (0 to 3 inches); brown (7.5YR 5/2) very cobbly silt loam, dark brown (7.5YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; 10 percent stones, 30 percent cobbles and 15 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (5 to 13 centimeters; 2 to 5 inches thick)
Bt1--8 to 18 centimeters (3 to 7 inches); reddish brown (5YR 5/3) very cobbly silty clay loam, reddish brown (5YR 5/3) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine roots; common very fine tubular pores; few faint clay films in pores and on ped faces; 5 percent stones 35 percent cobbles and 15 percent gravel; slightly acid (pH 6.5); clear wavy boundary.(8 to 18 cm; 3 to 7 inches thick)
Bt2--18 to 36 centimeters (7 to 14 inches); reddish brown (5YR 5/3) very cobbly clay, dark reddish brown (5YR 3/2) moist; strong fine and medium angular blocky structure; very hard, friable, very sticky and very plastic; common very fine roots; common very fine tubular pores; common distinct clay films on ped faces and in pores, 5 percent stones, 30 percent cobbles, and 15 percent gravel; slightly acid (pH 6.5); abrupt wavy boundary. (15 to 33 centimeters; 6 to 13 inches thick)
R--36 centimeters (14 inches); very hard andesite with few fractures about 10 to 30 centimeters (4 to 12 inches) apart.
TYPE LOCATION: San Clemente Island, Los Angeles County, California. About 1.57 miles south from intersection of main road and Mt. Thirst communications buildings, about .73 miles going Southeast from Shoba locked gate on main road and then 150 feet west to site.; 32.86091 degrees latitude, -118.42353 degrees longitude; UTM Zone 11, 3636765.57n, 366805.82e; U.S.G.S. Quad Name: San Clemente Island South, California.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 17.5 degrees C. (about 64 degrees F.). The soil temperature is above 8 degrees C. (47 degrees F.) all year.
Soil moisture: between depths of 15 to 33 centimeters (6 to 13 inches) or to a lithic contact is continuously moist in some or all parts from about December to about April and is dry from June to October.
Depth to lithic contact: 30 to 50 centimeters (12 to 20 inches).
Rock fragments content: 5 to 15 percent stones, 20 to 40 percent cobbles, and 15 to 25 percent gravel.
A horizon:
Dry color: 7.5YR 5/2, 4/2, lOYR 5/3, 6/2 or 6/3
Moist color: of 7.5YR 3/2, lOYR 4/2 or 4/3
Texture: very cobbly/stony silt loam or cobbly/stony silt loam
Clay content: 18 to 25 percent
Reaction: medium acid to neutral.
Bt horizons:
Dry color: 5YR 5/2, 5/3, 5/4 or 7.5YR 5/4
Moist color: 5YR 3/2, 3/3, 3/4 or 7/5YR 3/4
Texture: very cobbly silty clay loam in the upper part and very cobbly silty clay in the lower part
Rock fragment content: 5 to 10 percent stones, 20 to 35 percent cobbles and 15 to 30 percent gravel.
Clay content: 30 to 50 percent.
Reaction: slightly acid to mildly alkaline.
Some pedons have a Cr horizon immediately above the bedrock.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landscape: islands
Landform: hills and mountains
Slopes: 9 to 75 percent
Parent materials: volcanic rock such as andesite or dacite.
Elevation: 100 to 600 meters (330 to 1970 feet)
Climate: maritime with warm dry summers and mild moist winters.
Mean annual precipitation: 225 to 300 millimeters (9 to 12 inches.)
Mean annual temperature: 15.5 to 17.5 (60 to 64 degrees F.)
Frost-free season: 360 to 365 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Chinapoint soils: are moderately-deep to a paralithic contact and are on hills or terraces.
Eelpoint soils: have less than 35 percent rock fragments and are on hill or terraces.
Lostpoint soils: are deep to a paralithic contact and are on hills or terraces.
Shoba soils: are moderately-deep to a lithic contact and are on similar landforms.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, medium to very rapid runoff and low saturated hydraulic conductivity.
USE AND VEGETATION: The soils are used mostly for military maneuvers and to a minor extent for wildlife habitat. Vegetation consists of slender oats, stipa, soft chess, red brome, clover and lupine.
DISTRIBUTION AND EXTENT: San Clemente Island, Southern California Mountains, MLRA 20. These soils are not extensive.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Clemente Island, Los Angeles County, California, 1982. Series name is for Mount Thirst.
REMARKS:
Diagnostic horizons recognized in this pedon are:
Ochric epipedon: the zone from a depth of 0 to 8 centimeters
Argillic horizon: the zone from a depth of 8 to 36 centimeters
Lithic contact: at a depth of 36 centimeters
OSD revised during correlation of the San Clemente Island Interim Report in 2018.
ADDITIONAL DATA:
NASIS User Site/Pedon ID: 1982CA037THIRST
Classified using the Twelfth Edition Keys to Soil Taxonomy (2014)
National Cooperative Soil Survey
U.S.A.