LOCATION FLOMACK CA

Established Series
Rev. KDA-BRY-KP
12/2022

FLOMACK SERIES

The Flomack series consists of shallow, well drained soils on mountain slopes. These soils formed in colluvium over residuum derived from serpentinite. Slope is 30 to 65 percent. The mean annual precipitation is about 20 inches (51 centimeters) and the mean annual temperature is about 16 degrees C. (61 degrees F).

TAXONOMIC CLASS: Loamy, magnesic, thermic, shallow Typic Haploxeralfs

TYPICAL PEDON: Flomack gravelly sandy loam; on a southeast facing slope of 65 percent under bigberry manzanita, California foothill pine, leather oak, and buckbrush. The elevation is 844 meters (2,770 feet). (Color is for dry soil unless otherwise stated. When described on March 20, 2009 the soil was slightly moist throughout). The surface is covered by 50 percent 2 to 20 millimeter serpentine pebbles and 2 percent 75 to 250 millimeter serpentine cobbles.

A--0 to 7 centimeters (0 to 2 inches); light greenish gray (10Y 7/1) gravelly sandy loam, greenish gray (10Y 6/1) moist; weak medium platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine interstitial pores; 22 percent 2 to 20 millimeter pebbles and 5 percent 20 to 75 millimeter pebbles; strongly alkaline (pH 8.6); abrupt smooth boundary.

Bt1--7 to 21 centimeters (2 to 8 inches); brown (7.5YR 4/4) gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; moderate very coarse platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine interstitial pores; few faint clay bridges between sand grains; common fine prominent spherical yellowish red (5YR 5/8) dry, masses of oxidized iron with sharp boundaries in matrix; 16 percent 2 to 20 millimeter pebbles and 5 percent 20 to 75 millimeter pebbles; strongly alkaline (pH 8.7); clear smooth boundary.

Bt2--21 to 33 centimeters (8 to 13 inches); brown (7.5YR 4/4) gravelly sandy loam, dark brown (7.5YR 3/4) moist; weak very coarse platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine interstitial pores; few faint clay bridges between sand grains; many fine prominent spherical yellowish red (5YR 5/8) dry, masses of oxidized iron with sharp boundaries in matrix; 16 percent 2 to 20 millimeter pebbles and 5 percent 20 to 75 millimeter pebbles; strongly alkaline (pH 8.7); clear smooth boundary.

Cr--33 to 85 centimeters (13 to 33 inches); very weakly cemented serpentinite.

TYPE LOCATION: San Benito County, California, in Clear Creek Management Area; about 1.9 kilometers (1.2 miles) south-southwest of Clear Creek Mine; about 88.4 meters (290feet) north and 142.7 meters (840 feet) east of the southwest corner of section 11, T. 18 S., R. 11 E., Mount Diablo Base and Meridian; latitude 36 degrees 22 minutes 13.8 seconds north and longitude 120 degrees 44 minutes 46.10 seconds west; USGS San Benito Mountain, California Quadrangle, NAD83.

RANGE IN CHARACTERISTICS: Depth to paralithic contact is 25 to 51 centimeters (10 to 20 inches). Surface fragments are composed of serpentinite; 30 to 60 percent, 2 to 20 millimeter pebbles, 0 to 5 percent, 75 to 250 millimeter pebbles.

A horizon:
Hue: 10Y dry and moist
Value: 7 or 8 dry and moist
Chroma: 1 or 2 dry and moist
Texture of the fine earth fraction: sandy loam
Content of clay: 10 to 18 percent
Content of organic matter: 0.5 to 2.0 percent
Reaction: strongly alkaline
Content of rock fragments: 25 to 60 percent, 2 to 20 millimeter pebbles and 2 to 10 percent 20 to 75 millimeter pebbles.

Bt horizons:
Hue: 7.7YR dry and moist
Value: 4 dry and 3 moist
Chroma: 3 or 4 dry and moist
Texture of the fine earth fraction: sandy loam or sandy clay loam
Content of clay: 15 to 25 percent
Content of organic matter: 0.5 to 1.5 percent
Reaction: strongly alkaline
Content of rock fragments: 20 to 60 percent, 2 to 20 millimeter pebbles and 2 to 10 percent 20 to 75 millimeter pebbles.

COMPETING SERIES: There are no competing series at this time.

GEOGRAPHIC SETTING: Flomack soils are on mountain slopes at elevations of 816 to 1,532 meters (2,677 to 5,026 feet). Slope is 30 to 65 percent. Flomack soils formed in colluvium over residuum derived from serpentinite. The climate consists of hot dry summers and cool moist winters. Mean annual precipitation is 483 to 610 millimeters (19 to 24 inches). Mean annual temperature is 14 to 17 degrees C. (57 to 63 degrees F). Frost-free period is 150 to 200 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Atravesada, Delmexico, Cascara, and Idriapeak soils. Atravesada soils have a mollic epipedon. Delmexico soils have a mollic epipedon and are deep to a paralithic contact. Cascara soils do not have an argillic horizon. Idriapeak soils are moderately deep to a paralithic contact and have a loamy-skeletal particle size class.

DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; moderately saturated hydraulic conductivity.

USE AND VEGETATION: These soils are used for recreation and wildlife. The vegetation is usually nonexistent (barren) with scattered California foothill pines, bigberry Manzanita, leather oak, and buckbrush.

DISTRIBUTION AND EXTENT: These soils are in the Clear Creek Management Area San Benito and Fresno Counties, CA in the California Coast Ranges. They are not extensive. MLRA 15.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: San Benito County, California, 2009. Named after Florence Mack Mine that is in the area.

REMARKS: The modal pedon ID for the Flomack Series is 09CA069006 (Pedon number 09N0925). Magnesic mineralogy class is supported by the lab data and the serpentinite parent material.

ADDITIONAL DATA: Mean annual soil temperature at a depth of 50 cm (20 inches) is 17.9 degrees C (64 degrees F) at the typical profile site, based on 1 year's data (8/1/2009-8/1/2010) measured with a Onset Soil Temperature Recorder.

National Cooperative Soil Survey
U.S.A.