LOCATION MASTHEAD CA
Established Series
MEB/KP
06/2011
MASTHEAD SERIES
The Masthead series consists of moderately well drained soils that formed in schist and meta-sedimentary rock from slope alluvium and residuum. Masthead soils are on side slopes of interfluves of hills and mountains. Slopes range from 15 to 55 percent. The mean annual precipitation is about 355 millimeters (14 inches) and the mean annual air temperature is about 21 degrees Celsius (69 degrees F).
TAXONOMIC CLASS: Fine, smectitic, thermic Mollic Palexeralfs
TYPICAL PEDON: Masthead gravely silty loam, on a south west facing 30 percent slope under a cover of California sage, ferguss grass, Lemonade berry, scrub oaks and Toyon, at an elevation of 790 feet, (241 m). (Colors are for dry soil unless otherwise noted).
A--0 to 4 inches, (0 to 11 cm); brown (7.5YR 5/4) broken face gravelly silt loam, dark brown (7.5YR 3/3) broken face moist; 10 percent clay; moderate fine subangular blocky structure; slightly hard, loose, slightly sticky, slightly plastic; common very fine roots; 5 percent flat subrounded 75 to 250 millimeter cobbles and 10 percent flat subrounded 2 to 75 millimeter gravel; slightly alkaline, pH 7.7 by pH meter 1:1 water; clear wavy boundary. (6 to 14 centimeters thick)
Bt1--4 to 11 inches, (11 to 29 cm); reddish brown (5YR 5/3) broken face clay, dark reddish brown (5YR 3/3) broken face moist; 45 percent clay; strong medium angular blocky structure; hard, firm, very sticky, very plastic; common medium roots and common very fine roots; prominent clay films on rock fragments and prominent clay films on all faces of peds; 10 percent flat subrounded 2 to 75 millimeter gravel; slightly alkaline, pH 7.6 by pH meter 1:1 water; clear wavy boundary. (15 to 45 centimeters thick)
Bt2--11 to 30 inches, (29 to 75 cm); reddish brown (5YR 5/3) broken face gravelly clay, dark reddish brown (5YR 3/3) broken face moist; 50 percent clay; moderate medium angular blocky structure; hard, firm, very sticky, very plastic; prominent clay films on rock fragments and prominent clay films on all faces of peds; 15 percent flat and subrounded 75 to 250 millimeter cobbles and 15 percent flat and subrounded 2 to 75 millimeter gravel; moderately alkaline, pH 7.9 by pH meter 1:1 water; abrupt wavy boundary. (10 to 55 centimeters thick)
Cr--30 to 39 inches, (75 to 100 cm); very rigid Catalina schist; highly fractured (less than 10 cm apart).
TYPE LOCATION: Santa Catalina Island, Los Angeles County, California, in the Channel Islands Soil Survey Area 33 degrees, 23 minutes, 39 seconds North latitude and 118 degrees, 26 minutes, 9 seconds West longitude, NAD83 - U.S.G.S Quad: Santa Catalina Island East.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 15 to 22 degrees Celsius (59 to 71 degrees F.) The soil moisture control section is dry in all parts from about mid-June to mid-November and is usually moist the rest of the time.
The A horizon dry color is 10YR 5/4, 5/3, 7.5YR 6/4, 4/4, 5/3, 2.5Y 7/3. Moist color is 10YR 4/4, 7.5YR 3/3, 3/2, 2.5/2, 2.5Y 4/2.
Textures are sandy loam, very gravely sandy loam, silt loam, gravely silt loam, very gravely silt loam.
Coarse fragments may be 0 to 35 percent small gravels.
The A2 horizon dry color is 10YR 5/4, 5/3, 7.5YR 6/4, 4/4, 5/3, 2.5Y 7/3. Moist color is 10YR 4/4, 7.5YR 3/3, 3/2, 2.5/2, 2.5Y 4/2.
Textures are sandy loam, very gravely sandy loam, silt loam, gravely silt loam, very gravely silt loam.
Coarse fragments may be 0 to 35 percent small gravels.
The Bt1 horizon dry color is 10YR 5/2, 3/3, 7.5YR 3/4, 5YR 5/3. Moist color is 10YR 3/3, 7.5YR 3/3, 3/2, 5YR 3/3.
Textures are clay loam, gravely silt loam, clay.
Coarse fragments may be 0 to 45 percent small gravels.
The Bt2 horizon dry color is 10YR 3/2, 5YR 5/3, 5Y 5/2. Moist color is 10YR 4/3, 3/3, 7.5YR 3/3, 3/2 5YR 3/3.
Textures are silt loam, gravely silty clay loam, sandy clay, clay loam, clay gravely clay.
Coarse fragments may be 0 to 30 percent small gravels.
The Bt3 horizon dry color is 5YR 5/4, 2.5Y 4/3. Moist color is 10YR 4/3, 2.5Y 4/3, 3/2.
Textures are silty clay loam, gravely silty clay, clay loam, very gravely clay loam, clay.
Coarse fragments may be 0 to 20 percent small gravels.
The Cr horizon ranges from soft, platy to hard nonflat rock of Catalina schist, Chlorite-actinolite-talc mlange, quartz-muscovite gneissoid, or green-hornblend gneiss.
COMPETING SERIES: These are the
Bapos (CA),
Benridge (CA),
Hellman (CA),
Honker (CA),
Kimball (CA),
Milpitas (CA),
Newville (CA),
Positas (CA),
Tierra (CA) and
Wappo series. Bapos soils are greater than 60 inches deep and are on fans and terraces. Benridge soils are greater that 60 inches deep and have mineralogy dominated by amorphous material. Hellman soils are greater than 60 inches deep and become more acid with depth. Honker soils are on sandstone and frost free days less than 260. Kimball soils are very deep or have duripans below 40 inches. Milpitas soils are very deep and are on terraces from alluvium. Newville soils are very deep. Positas soils are deep and have less then 280 frost free days. Tierra soils are deep and are on terraces from alluvium. Wappo soils are very deep in aluuvium and have less than 205 frost free days.
GEOGRAPHIC SETTING: Masthead soils formed in schist (Catalina schist) and associated meta sedimentary materials (Franciscan formation) side slopes of interfluves of hills and mountains on islands. Slopes range from 5 to 75 percent. Elevations are from sea level to 1550 feet (0 to 472 meters). The climate is characterized by warm, dry summers and cool, moist winters with potential fog common all year. The mean annual precipitation is 13 to 24 inches (330 to 660 mm), the mean annual temperature is 61 to 73 degrees F. (16 to 23 degrees C.), and the frost free season is 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Coastwise, and
Dewpoint. Coastwise soils are shallow. Dewpoint soils are mesic and found under dense shrubs and oaks. These soils are found on hills and mountains.
DRAINAGE AND PERMEABILITY: moderately well drained; moderately high runoff; moderate permeability.
USE AND VEGETATION: Wildlife habitat, recreation and building site development. Vegetation is low shrubs and annual grasses, California sage, ferguss grass, Lemonade berry, Lural sumac, scrub oaks and Toyon.
DISTRIBUTION AND EXTENT: Santa Catalina Island, Los Angeles County, California. The soil is not extensive. MLRA 20.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Santa Catalina Island, Los Angeles County, California, 2008.
REMARKS: The series name is coined. Diagnostic horizons and features recognized in this pedon:
Diagnostic horizons and features recognized in this pedon are:
Ochric Epipedon 0 to 11 cm (0 to 4 in)
Argillic Horizon 11 to 61 cm (4 to 24 in)
ADDITIONAL DATA:
NSSL Laboratory Pedon Sample #:06N0792, 06N0793
National Cooperative Soil Survey
U.S.A.