LOCATION COLOLAG NV
Established Series
Rev. DJM/JVC
04/2015
COLOLAG SERIES
The Cololag series consists of very deep, well drained soils that formed in alluvium derived from igneous, metamorphic and sedimentary rock. Cololag soils are on fan fan remnant summits. Slope ranges from 0 to 15 percent. The mean annual precipitation is about 4 inches and the mean annual temperature is about 74 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, hyperthermic Typic Calciargids
TYPICAL PEDON: Cololag extremely gravelly sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 60 percent pebbles and 5 percent cobbles.
A--0 to 3 inches; light brown (7.5YR 6/4) extremely gravelly sandy loam, brown (7.5YR 4/4) moist; strong medium and coarse platy structure; slightly hard, friable, slightly sticky and nonplastic; few very fine roots; common fine interstitial and few fine tubular pores; 60 percent pebbles and 5 percent cobbles; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (2 to 5 inches thick)
Bk1--3 to 14 inches; light brown (7.5YR 6/4) extremely gravelly loamy sand, strong brown (7.5YR 5/6) moist; massive; slightly hard, friable, nonsticky and nonplastic; many very fine and few fine medium roots; many very fine and fine interstitial and few fine tubular pores; many (30 percent) medium calcium carbonate coats on bottom of rock fragments; 65 percent pebbles; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 12 inches thick)
Btk--14 to 24 inches; light reddish brown (5YR 6/4) very gravelly sandy loam, yellowish red (5YR 5/6) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; few fine interstitial and few fine and medium tubular pores; discontinuous extremely weakly cemented calcium carbonate masses; few faint clay films bridging sand grains; common (15 percent) fine calcium carbonate coats on coarse sand grains; medium coats on bottom of rock fragments; 35 percent pebbles and 5 percent cobbles; violently effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (8 to 12 inches thick)
B'k2--24 to 31 inches; pink (5YR 7/3) gravelly sandy loam, yellowish red (5YR 5/6) moist; massive; very hard, extremely firm, slightly sticky and slightly plastic; few fine tubular and few fine interstitial pores; discontinuous moderate cementation; many (45 percent) fine and medium calcium carbonate masses and many (70 percent) medium calcium carbonate coats on bottom of rock fragments; 25 percent pebbles; violently effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (6 to 8 inches thick)
B'k3--31 to 65 inches; pink (5YR 7/4) extremely gravelly sandy loam, yellowish red (5YR 4/6) moist; massive; hard, firm, slightly sticky and slightly plastic; few fine tubular and few fine interstitial pores; discontinuous weak calcium carbonate cementation; many (30 percent) fine and medium calcium carbonate coats on bottom of rock fragments; 70 percent pebbles; violently effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Clark County, Nevada; in the Lake Mead National Recreation Area about 2 miles due east of the junction of Northshore Road and the Overton Beach Road; 2,500 feet north and 470 feet west of the southeast corner of section 21, T. 17 S., R. 68 E.; USGS Valley of Fire East, NV 7.5 minute topographic quadrangle; 36 degrees, 26 minutes, 24.8 seconds north latitude and 114 degrees 23 minutes 26.8 seconds west longitude; UTM 11s, 733874e, 4035942n; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in some part during winter and spring and intermittingly moist in the upper part following summer convection storms; typic aridic soil moisture regime.
Soil temperature - 72 to 78 degrees F.
Depth to calcic horizon - 2 to 5 inches.
Depth to argillic horizon - 10 to 17 inches.
Depth to the base of the argillic horizon: 18 to 29 inches.
Reaction - Moderately alkaline or strongly alkaline.
Other features: B horizons have 0 to 20 percent weakly through moderately calcium carbonate cementation.
Control section - Clay content: 10 to 18 percent
Rock fragments: 35 to 50 percent, mainly gravel.
A horizon - Hue: 5YR or 7.5YR.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Bk1 horizon - Hue: 5YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 4 through 6, dry or moist.
Texture: Loamy sand, sandy loam, or fine sandy loam.
Clay content: 3 to 12 percent.
Rock fragments: 45 to 70 percent gravel.
Calcium carbonate equivalent in the fine earth fraction: 10 to 20 percent.
Btk horizon - Hue: 5YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 4 through 6, dry or moist.
Texture: Sandy loam or fine sandy loam.
Clay content: 10 to 18 percent.
Rock fragments: 35 to 50 percent, mainly gravel.
Calcium carbonate equivalent in the fine earth fraction: 5 to 10 percent.
B'k2 horizon - Hue: 5YR or 7.5YR.
Value: 6 or 7 dry.
Clay content: 8 to 15 percent.
Rock fragments: 20 to 50 percent, mainly gravel.
Consistence: Hard or very hard, dry.
Calcium carbonate equivalent in the fine-earth fraction: 15 to 25 percent.
B'k3 horizon - Hue: 5YR or 7.5YR.
Value: 6 or 7 dry.
Clay content: 8 to 15 percent.
Rock fragments: 50 to 75 percent, mainly gravel.
Consistence: Hard or very hard, dry.
Calcium carbonate equivalent in the fine-earth fraction: 15 to 25 percent.
COMPETING SERIES: These are the
Chuckawalla,
Cristobal and
Pinamt series. Chuckawalla and Pinamt soils average more than 18 percent clay in the particle-size control section. Cristobal soils are more than 40 inches to the base of the argillic horizon.
GEOGRAPHIC SETTING: Cololag soils are on fan remnant summits. These soils formed in alluvium derived from igneous, metamorphic and sedimentary rock.. Slope ranges from 0 to 15 percent. Elevations are 800 to 1,700 feet. The climate is arid with warm, moist winters and hot, dry summers. The mean annual precipitation is 3 to 5 inches, the mean annual temperature is 70 to 76 degrees F., and the frost-free period is 300 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Cololag soils are associated with the miscellaneous land type Badland.
DRAINAGE AND PERMEABILITY: Well drained; low runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly white bursage, creosotebush, and range ratany.
DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada; MLRA 30; These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County, Nevada, 1998. The name is coined.
REMARKS: Diagnostic horizon and features recognized in this pedon are:
Ochric epipedon - 0 to 3 inches (A horizon).
Calcic horizon - 3 to 65 inches (Bk1, Btk, B'k2, and B'k3 horizons).
Argillic horizon - 14 to 24 inches (Btk horizon).
Particle-size control section - 14 to 24 inches (Btk horizon).
Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 9/2006. ET
National Cooperative Soil Survey
U.S.A.