LOCATION GEMCITY AZ
Tentative Series
Rev. JMH/HAH/NMS
05/2021
GEMCITY SERIES
The Gemcity series consists of moderately deep, well drained, moderately slowly permeable soils formed in residuum of basalt. Gemcity soils are on old basalt capped mesas. Slope is 0 to 15 percent. Mean annual precipitation is about 10 inches and mean annual air temperature is about 53 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ustic Calciargids
TYPICAL PEDON: Gemcity loam-rangeland/habitat. (Colors are for dry soil unless otherwise noted.)
C1--0 to 1 inch (0 to 3 centimeters); black (7.5YR 2.5/1) extremely gravelly coarse sand, black (7.5YR 2.5/1) moist; 3 percent clay; single grain; loose, nonsticky, nonplastic; common very fine roots throughout; many interstitial pores; 60 percent cinders; noneffervescent; moderately alkaline, pH 8.0; abrupt smooth boundary.
C2--1 to 6 inches (3 to 15 centimeters); very dark grayish brown (10YR 3/2) gravelly sandy loam, black (10YR 2/1) moist; 17 percent clay; weak medium granular and thin platy structure; soft, very friable, slightly sticky, slightly plastic; many very fine and common fine roots throughout; common very fine dendritic tubular pores; 20 percent cinders; noneffervescent; moderately alkaline, pH 8.0; abrupt smooth boundary.
2Bt--6 to 10 inches (15 to 25 centimeters); dark brown (10YR 3/3) sandy clay loam, very dark brown (10YR 2/2) moist; 33 percent clay; moderate medium angular blocky structure; slightly hard, friable, very sticky, moderately plastic; many very fine roots throughout; common very fine dendritic tubular pores; very few faint thin clay films on all faces of peds; slightly effervescent, 4 percent calcium carbonate equivalent; moderately alkaline, pH 8.2; clear smooth boundary.
2Bk1--10 to 20 inches (25 to 51 centimeters); pale brown (10YR 6/3) gravelly sandy clay loam, brown (10YR 5/3) moist; 28 percent clay; weak medium subangular blocky structure; slightly hard, friable, moderately sticky, moderately plastic; common very fine roots throughout; common very fine dendritic tubular pores; common carbonate masses in matrix; 5 percent cobbles and 22 percent gravel; strongly effervescent, 21 percent calcium carbonate equivalent; moderately alkaline, pH 8.2; gradual wavy boundary.
2Bk2--20 to 31 inches (51 to 79 centimeters); light gray (10YR 7/2) gravelly sandy loam, brown (10YR 5/3) moist; 19 percent clay; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common very fine roots throughout; common very fine irregular pores; common carbonate masses in matrix and around rock fragments; 30 percent gravel; violently effervescent, 40 percent calcium carbonate equivalent; strongly alkaline, pH 9.0; abrupt wavy boundary.
2R--31 inches (79 centimeters); fractured, unweathered basalt.
TYPE LOCATION: Coconino County, Arizona; Location by Universal Transverse Mercator System: Zone 12N, 3933159 Northing, 451999 Easting.
RANGE IN CHARACTERISTICS:
Soil moisture: Ustic aridic soil moisture regime
Depth to bedrock: 20 to 40 inches
Particle-size control section: 18 to 35 percent clay
A horizon
Hue: 5 YR, 7.5YR, 10YR
Value: 3 through 5, dry or moist
Chroma: 3 or 4, dry or moist
Texture: fine sandy loam, loam, cobbly loam, gravelly loam, stony loam
Bt and Btk horizon
Hue: 5YR, 7.5YR, 10YR
Value: 3 through 7 dry, 2.5 through 6 moist
Chroma: 2 through 4, dry or moist
Texture: loam, clay loam, sandy clay loam, fine sandy loam
Rock fragments: 0 to 10 percent cobbles
Bk horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 through 7 dry, 4 through 6 moist
Chroma: 2 through 6, dry or moist
Texture: loam, clay loam, sandy loam, sandy clay loam
Rock fragments: 0 to 15 percent gravel, 0 to 10 percent cobbles
Calcium carbonate equivalent: more than 15 percent
COMPETING SERIES: These are the
Alvey (UT),
Barx (UT),
Cabreros (NM),
Cerrillos (NM),
Clovis (NM),
Fernando (NM),
Flaco (NM).
Horchata (NM),
Maysdorf (WY),
Millett (AZ),
Palabria (NM),
Progresso (CO),
Sanostee (NM),
Scholle (NM),
Selpats (WY),
Solirec (UT),
Spenlo (UT),
Threetop (WY), and
Wineg (AZ) series. Alvey, Barx, Cerrillos, Clovis, Fernando, Maysdorf, Millett, Scholle, Selpats, Solirec, Spenlo, and Wineg soils are very deep. Horchata, Progresso, and Threetop soils are moderately deep to a lithic contact. Cabreros soils are moderately deep to a paralithic contact. Palabria soils are deep to a lithic contact. Flaco soils are formed in alluvium and eolian deposits derived from basalt.
GEOGRAPHIC SETTING: Gemcity soils are on moderately weathered lava flows of basalt. They formed in residuum derived from basalt. Slopes range from 0 to 15 percent. Elevations range from 5,300 to 6,800 feet. The average annual precipitation ranges from 10 to 14 inches, and the mean annual air temperature ranges from 49 to 57 degrees F. The average frost-free period is 120 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Wupatki, and
Wukoki soils. The Wupakti soils have a duripan at depths less than 20 inches. Wukoki soils have a strongly contrasting particle-size at depths less than 40 inches.
DRAINAGE AND PERMEABILITY: Well drained medium runoff; moderately slow permeability.
USE AND VEGETATION: Gemcity soils are used for habitat and livestock grazing. Present native vegetation is black grama, galleta, alkali sacaton, apache plume, and one-seed juniper.
DISTRIBUTION AND EXTENT: The series is of small extent in northern Arizona. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Coconino County, Arizona, 2016
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Argillic horizon - the zone from 6 to 10 inches (2Bt and 2Btk horizons)
Calcic horizon - the zone from 10 to 31 inches (2Bk horizons)
The epipedon is neither mollic nor ochric because rock structure exists in surface fragments and within the upper two horizons.
The name Gemcity originates from the name given to a lava flow in the vicinity of the typical pedon.
Classified according to Keys to Soil Taxonomy, Twelfth Edition, 2014.
ADDITIONAL DATA: S2012AZ0050003 NSSL Lincoln.
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National Cooperative Soil Survey
U.S.A.