LOCATION DEWPOINT CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, isothermic Typic Paleustalfs
TYPICAL PEDON: Dewpoint sandy loam, on a north west facing 42 percent slope under a cover of oaks, toyon, crossosoma, ceanothus, lemonade sumac, and laurel sumac at an elevation of 682 feet, (208 m). (Colors are for dry soil on the broken face of the peds unless otherwise noted).
Oi--0 to 1 inches, (0 to 3 cm); moderate medium subangular blocky; soft, 8 percent flat rounded 2 to 75 millimeter gravel clear wavy boundary. (2 to 9 centimeters thick)
A--1 to 6 inches, (3 to 16 cm); very dark grayish brown (10YR 3/2) sandy loam, very dark brown (10YR 2/2) moist; 14 percent clay; moderate fine subangular blocky and moderate medium granular structure; soft, very friable, non-sticky, slightly plastic; few fine roots throughout and common very fine roots throughout; common fine moderate continuity interstitial and common very fine low continuity tubular pores; 30 percent rounded 2 to 75 millimeter gravel; slightly acid, pH 6.6 by pH meter 1:1 water; clear wavy boundary. (13 to 25 centimeters thick)
A2--6 to 11 inches, (16 to 29 cm); pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; 15 percent clay; strong coarse subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; common fine roots throughout and few medium roots throughout and few very fine roots throughout; common fine moderate continuity irregular and common very fine low continuity tubular pores; continuous faint brown (10YR 4/3), moist, clay films on surfaces along root channels and continuous faint brown (10YR 4/3), moist, clay films between sand grains; 1 percent flat rounded 75 to 250 millimeter cobbles and 34 percent rounded 2 to 75 millimeter gravel; moderately acid, pH 6.1 by pH meter 1:1 water; clear wavy boundary. (0 to 34 centimeters thick)
Bt1--11 to 18 inches, (29 to 46 cm); dark brown (7.5YR 3/3) gravelly clay, dark brown (7.5YR 3/3) moist; 36 percent clay; moderate medium angular blocky structure; very hard, firm, very sticky, very plastic; common fine roots throughout and common medium roots throughout and common very fine roots throughout; common very fine low continuity tubular pores; continuous prominent very dark grayish brown (10YR 3/2), moist, clay films on rock fragments and continuous prominent very dark grayish brown (10YR 3/2), moist, clay films on all faces of peds; 7 percent flat rounded 75 to 250 millimeter cobbles and 30 percent rounded 2 to 75 millimeter gravel; slightly acid, pH 6.4 by pH meter 1:1 water; gradual wavy boundary. (17 to 32 centimeters thick)
Btb2--18 to 33 inches, (46 to 85 cm); dusky red (2.5YR 3/2) gravelly clay, dusky red (2.5YR 3/2) rubbed moist; 49 percent clay; moderate medium angular blocky structure; very hard, very firm, very sticky, very plastic; common medium roots throughout; common very fine low continuity tubular pores; 85 percent continuous prominent very dark grayish brown (10YR 3/2), moist, clay films on rock fragments and 85 percent continuous prominent very dark grayish brown (10YR 3/2), moist, clay films on all faces of peds; 17 percent flat rounded 75 to 250 millimeter cobbles and 9 percent rounded 2 to 75 millimeter gravel; neutral, pH 7.2 by pH meter 1:1 water; abrupt wavy boundary. (0 to 39 centimeters thick)
R--33 inches, (85 to 100 cm); very rigid cobble and stone size bedrock, Catalina Island Schist.
TYPE LOCATION: Santa Catalina Island, Los Angeles County, California, in the Channel Islands Soil Survey Area 33 degrees, 23 minutes, 44 seconds North latitude and 118 degrees, 26 minutes, 24 seconds West longitude, NAD83 - U.S.G.S Quad: Santa Catalina Island East.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 15 to 17 degrees Celsius (59 to 63 degrees F.) The difference between mean summer and mean winter temperatures ranged from 4 to 5 degrees Celsius. The soil moisture control section is dry in all parts from about mid-June to mid-November and is usually moist in some part the rest of the time.
The O horizon:
Coarse fragments: 0 to 35 percent small gravels
The A1 and A2 horizon:
Dry color is 10YR 6/3, 5/3, 4/4, 4/2, 3/2, 7.5YR 3/4. Moist color is 10YR 4/3 3/3, 3/2, 2/2, 7.5YR 3/3, 3/2.
Textures: sandy loam, gravely sandy loam, loam, silt loam.
Coarse fragments: 0 to 35 percent small gravels.
The Bt1 and Bt2 horizon:
Dry color is 10YR 4/4, 3/2, 7.5YR 3/3, 3/4. Moist color is 10YR 3/2, 3/3, 7.5YR 3/3, 3/2
Textures: loam, clay loam, silty clay loam, silty clay, clay, gravely clay.
Coarse fragments: 0 to 35 percent small gravels.
The Bt3 and Btk (when present) horizons:
Dry color is 5Y 4/4, 4/3, 2.5Y 3/2. Moist color is 5Y 3/2.
Textures: gravely clay, sandy clay.
Coarse fragments: 0 to 30 percent small gravels.
The R horizon ranges from soft Cr like rock, platy to very rigid rock of Catalina schist, chlorite-actinolite-talc mlange, quartz-muscovite gneiss, or green-hornblende gneiss.
Abrupt textural changes range between 20 and 42 percent clay increase between the A and Bt horizons, usually within 2.5 to 10 cm in depth.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Dewpoint soils formed in schist and meta-sedimentary rock. Typically the parent material is from Catalina schist and associated Franciscan formation meta-sedimentary rock, but may not be restricted to these specific formations. Dewpoint is on 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 ranges from 7 to 17 inches (178 to 432 mm), the mean annual temperature is 59 to 66 degrees F. (15 to 19 degrees C.), and the frost free season is 355 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coastwise, Masthead. Coastwise soils are shallow. Masthead soils are thermic and generally found on south-facing slopes under grasses and sage. All 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 predominately Island Chaparral, and Island Woodland, also Non-native Scrub and Coastal Sage Scrub.
DISTRIBUTION AND EXTENT: Santa Catalina Island, Los Angeles County, California. The soil is not extensive. MLRA 20 - Southern California Mountains.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Santa Catalina Island, Los Angeles County, California, 2008.
REMARKS:
Dewpoint soils are isothermic borderline isomesic. The iso classification dictates the moisture regime to not be xeric. These soils are possibly in the Aridic subgroup. Moisture control section data is needed for this classification.
Diagnostic horizons and features recognized in this pedon are:
Argillic Horizon 11 to 33 inches (29 to 85 cm)
Abrupt Textural Change: 20 to 42 percent clay increase between the A and Bt horizons usually within 10 cm.
ADDITIONAL DATA:
Pedon information for this type location only:
Pedon Site ID: s06037c111; Lab Pedon #: 06N0795