LOCATION MORMOUNT                NV

Established Series
Rev. RWW-DJM-RLB
11/2015

MORMOUNT SERIES

The Mormount series consists of shallow to a petrocalcic, well drained soils that formed in alluvium predominantly from limestone with minor amounts of volcanic tuffs. The Mormount soils are on fan piedmont remnants. Slopes are 2 to 15 percent. The mean annual precipitation is about 8 inches. The mean annual temperature is about 58 degrees F.

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Argic Petrocalcids

TYPICAL PEDON: Mormount gravelly very fine sandy loam, rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with 23 percent pebbles and 2 percent cobbles.

A--0 to 3 inches; brown (7.5YR 5/4) gravelly very fine sandy loam, brown (7.5YR 4/4) moist; weak thin platy structure; soft, very friable, nonsticky and slightly plastic; many very fine roots; many very fine irregular and few very fine tubular pores; 20 percent pebbles; slightly effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (2 to 4 inches thick)

Btk1--3 to 9 inches; light brown (7.5YR 6/4) gravelly very fine sandy loam, brown (7.5YR 5/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and plastic; many very fine and few medium roots; many very fine and fine and few medium tubular pores; common thin clay films on faces of peds and lining pores; many thin lime coats on undersides of rock fragments; 20 percent pebbles; strongly effervescent; moderately alkaline (pH 8.4); gradual smooth boundary. (5 to 8 inches thick)

Btk2--9 to 15 inches; light brown (7.5YR 6/4) gravelly very fine sandy loam, brown (7.5YR 5/4) moist; moderate fine subangular blocky structure; soft, very friable, sticky and plastic; common very fine and fine and few medium roots; common very fine and fine and few medium tubular pores; common thin clay films coating ped faces and pores; many thin lime coats and pendants on vertical and undersides of rock fragments; common fine irregularly shaped lime filaments and seams; 25 percent pebbles and 5 percent cobbles; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (4 to 8 inches thick)

Btk3--15 to 19 inches; light brown (7.5YR 6/4) gravelly sandy clay loam, brown (7.5YR 5/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine and fine and few medium roots; common very fine and few fine and medium tubular pores; many thin clay films on faces of peds, lining pores and bridging mineral grains; many thick lime coats and pendants on vertical and undersides of rock fragments; many medium irregularly shaped lime filaments and seams; 20 percent pebbles and 10 percent cobbles; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (3 to 6 inches thick)

Bkm--19 to 60 inches; very pale brown (10YR 8/2) indurated petrocalcic hardpan, very pale brown (10YR 7/3) moist; massive; extremely hard; 1/4 to 1 inch continuous carbonate laminae in upper part; violently effervescent.

TYPE LOCATION: Southeastern Lincoln County, Nevada; Approximately 5 miles northwest of Davidson Peak and 350 feet west and 750 feet south of the projected northeast corner of section 26, T.11 S, R.68 E; and 36 degrees, 57 minutes and 21 seconds north latitude and 114 degrees, 20 minutes and 43 seconds west longitude.

RANGE IN CHARACTERISTICS:

Soil moisture - Usually dry, moist in late summer and for short periods in winter and spring. Typic aridic soil moisture regime.
Soil temperature - 59 to 64 degrees F.
Depth to petrocalcic horizon - Ranges from 14 to 20 inches.

Control section - Clay content: Averages 18 to 27 percent.
Rock fragments: 15 to 35 percent predominantly pebble-size pan fragments.

A horizon - Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 3 or 4 dry or moist.

Btk horizons - Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4 dry, or moist.
Texture: Gravelly very fine sandy loam, gravelly loam, gravelly sandy clay loam and gravelly clay loam.
Other features: Common thin to thick lime coats and pendants on vertical and undersides of rock fragments; Lower horizons commonly contain lime occurring as irregularly shaped filaments and seams.

Bkm horizon - Cementation: Very strongly cemented or indurated.
Other features: Petrocalcic horizon ranges from 3 to 20 feet thick.

COMPETING SERIES: These are the Jerag(NM) and Palo(T NM) series. Jerag and Palo soils have approximately 14 inches of precipitation with over 1/2 of the total falling in June through September, and lacks a petrocalcic horizon over 3 feet thick. The Palo series do not have a Btk horizon above the indurated pan.

GEOGRAPHIC SETTING: Mormount soils are on fan piedmont remnants. The exposed petrocalcic horizon is as thick as 20 feet in some pedons. These soils formed in alluvium predominantly from limestone and minor amounts of volcanic tuffs. Slopes are 2 to 15 percent. Elevations are 3500 to 4500 feet. The climate is semiarid with cool, moist winters and hot, intermittently moist summers. The mean annual precipitation is 5 to 8 inches. The mean annual temperature is 57 to 62 degrees F., and the frost-free season is 190 to 210 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arizo and Sote series. Arizo and Sote soils both lack an argillic horizon and a petrocalcic horizon.

DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.

USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly blackbrush, creosotebush, yucca, Nevada ephedra, big galleta, rabbitbrush and desert needlegrass.

DISTRIBUTION AND EXTENT: Southeastern Nevada. These soils are not extensive. MLRA 30.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: Lincoln County, Nevada, South Part, 1992.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Argillic horizon - The zone from about 3 to 19 inches. (Btk1, Btk2 and Btk3 horizons)

Petrocalcic horizon - The zone from about 19 to 60 inches. (Bkm horizon)

Particle-size control section - The zone from about 3 to 19 inches. (Btk1, Btk2 and Btk3 horizons)

Responsibility for this series was transferred from Davis to Phoenix 11/2015. The last revision to the series was 6/2006. ET

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National Cooperative Soil Survey
U.S.A.