LOCATION IRONGOLD NV

Established Series
Rev. LJL/TM/RLB
04/2015

IRONGOLD SERIES

The Irongold series consists of shallow to a hardpan, well drained soils that formed in alluvium from limestone. Irongold soils are on fan remnants. Slope ranges from 2 to 15 percent. The mean annual precipitation is about 6 inches and the mean annual temperature is about 60 degrees F.

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

TYPICAL PEDON: Irongold extremely gravelly loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 65 percent pebbles, 5 percent cobbles and 1 percent stones.

A1--0 to 1 inch; pale brown (10YR 6/3) extremely gravelly loam, brown (10YR 4/3) moist; strong thick platy structure parting to moderate medium platy; soft, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine and few fine vesicular pores; 65 percent pebbles, 5 percent cobbles and 1 percent stones; violently effervescent (17 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.4); clear smooth boundary. (1 to 3 inches thick)

A2--1 to 7 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; moderate fine and medium platy structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine vesicular and few very fine and fine interstitial pores; 15 percent pebbles; violently effervescent (18 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.4); clear smooth boundary. (4 to 8 inches thick)

Bk--7 to 11 inches; light yellowish brown (10YR 6/4) very gravelly loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; common very fine and few fine tubular and interstitial pores; many thin calcium carbonate coats and pendants on the undersides of rock fragments; 35 percent pebbles, 3 percent cobbles and 2 percent stones; violently effervescent (25 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.4); abrupt wavy boundary. (3 to 5 inches thick)

Bkm--11 to 34 inches; white (10YR 8/1) continuous weakly cemented petrocalic, very pale brown (10YR 8/2) moist; weak very thick platy structure; very hard, very firm, brittle; common very fine and few fine roots in fractures; thin continuous laminar cap (1 millimeter) covering plates; 80 percent of hardpan dissolves in concentrated hydrochloric acid; violently effervescent; clear wavy boundary. (18 to 30 inches thick)

2Bk--34 to 60 inches; very pale brown (10YR 7/3) extremely gravelly loamy coarse sand, pale brown (10YR 6/3) moist; massive; hard, firm, nonsticky and nonplastic; few very fine roots; many very fine and few fine and medium interstitial pores; many thin calcium carbonate coats and pendants on the undersides of coarse fragments; 30 percent discontinuous weak cementation in bands; 75 percent pebbles; violently effervescent (60 percent calcium carbonate equivalent in the fine earth fraction); strongly alkaline (pH 8.8).

TYPE LOCATION: Clark County, Nevada; approximately 2.7 miles northwest of Goodsprings, Nevada; about 690 feet west and 2820 feet south of the northeast corner of section 16, T. 24 S., R. 58 E.; USGS Goodsprings, NV 7.5 minute topographic quadrangle; 35 degrees, 51 minutes, 39 seconds north latitude and 115 degrees, 28 minutes, 13 seconds west longitude; UTM 11, 638117e, 3969594n; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture - Usually dry, moist in some part for short periods during winter and early spring and for 10 to 20 days cumulative between July to October following convection storms. The soils have a typic aridic moisture regime.

Soil temperature - 59 to 64 degrees F.

Depth to petrocalcic - 10 to 14 inches.

Control section - Percent clay: 8 to 16 percent.
Rock fragments: Averages 15 to 35 percent, mainly gravel.
Calcium carbonate equivalent of the less than 20 millimeter fraction: 25 to 40 percent.

A horizons - Chroma: 3 or 4 moist and dry.
Calcium carbonate equivalent in the fine earth fraction: 15 to 30 percent.

Bk horizon - Value: 4 or 5 moist.
Chroma: 4 through 6.
Texture: Loam or sandy loam.
Clay content: 8 to 16 percent.
Rock fragments: 15 to 45 percent, mainly pebbles.
Calcium carbonate equivalent in the fine earth fraction: 20 to 30 percent.
Other features: Some pedons contain common fine soft calcium carbonate nodules.

Bkm horizon - Structure: Platy or massive.
Cementation: Weakly or moderately cemented.

2Bk horizon - Consistence: Slightly hard or hard, friable or firm.
Clay content: 2 to 8 percent.
Rock fragments: 65 to 80 percent, mainly pebbles.
Calcium carbonate equivalent in the fine earth fraction: 50 to 70 percent.

COMPETING SERIES: This is the Cave (NV), Goodsprings (NV), Simona (NM) and Vace (NV) series. The Cave ,Simona and Vace soils have indurated petrocalcic horizons. Goodsprings soils have hues of 7.5YR or 5YR and MAST of 64 to 70 degrees F. Simona soils have less than 15 percent rock fragments in the particle-size control section.

GEOGRAPHIC SETTING: Irongold soils are on fan remnants. These soils formed in alluvium from limestone. Slope ranges from 2 to 15 percent. Elevations are 3,000 to 5,000 feet. The climate is hot and arid with warm, moist winters and hot, dry summers. The mean annual precipitation is 5 to 7 inches; mean annual temperature is 57 to 63 degrees F., and the frost-free season is 180 to 240 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Weiser series. Weiser soils have more than 50 percent rock fragments, are very deep and lack a petrocalcic horizon.

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

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly blackbrush, Nevada ephedra, creosotebush and big galleta.

DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada. MLRA 30. These soils are moderately extensive.

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

SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County, Nevada, 1994. The name is coined from the Iron Gold Mine which is located 1.3 miles to the south.

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

Ochric epipedon - 0 to 7 inches (A1 and A2 horizons).

Petrocalcic horizon - 11 to 34 inches (Bkm horizon).

Particle-size control section - 0 to 11 inches (A1, A2 and Bk horizons).

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 7/2006. ET

National Cooperative Soil Survey
U.S.A.