LOCATION JURATRIAS               CA

Established Series
Rev: LJL/PBF/ET
09/2015

JURATRIAS SERIES

The Juratrias series consists of very shallow to bedrock, well drained soils that formed in residuum and colluvium from metamorphic materials. Juratrias soils are on mountains. Slope ranges from 15 to 50 percent. The mean annual precipitation is about 8 inches and the mean annual air temperature is about 56 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, nonacid, mesic Lithic Torriorthents

TYPICAL PEDON: On Juratrias-Mulespring-Newera complex, 8 to 50 percent slopes at an elevation of 5,070 feet. (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 75 percent gravel, 5 percent cobbles and 2 percent stones.

A -- 0 to 3 inches; light yellowish brown (10YR 6/4) extremely gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and few fine interstitial and tubular pores; 75 percent gravel, 5 percent cobbles and 2 percent stones; noneffervescent; slightly alkaline (pH 7.4); clear wavy boundary. (1 to 4 inches thick)

Bw -- 3 to 7 inches; yellowish brown (10YR 5/4) extremely gravelly loam, dark yellowish brown (10YR 4/4) moist; moderate medium and coarse subangular blocky structure; moderately hard, very friable, slightly sticky and moderately plastic; common very fine and few fine roots; common very fine and few fine interstitial and tubular pores; 10 percent discontinuous distinct clay films on rock fragments; 60 percent gravel, 5 percent cobbles and 2 percent stones; noneffervescent; slightly alkaline (pH 7.4); abrupt wavy boundary. (2 to 6 inches thick)

R -- 7 inches; moderately fractured hard metamorphic bedrock; 70 percent discontinuous distinct clay films on rock faces.

TYPE LOCATION: San Bernardino County, California; about 3.1 miles due east of Avawatz Pass in the Avawatz Mountains; 2,900 feet north and 1,000 feet east of the southwest corner of T. 17 N., R. 6 E.; 35 degrees, 31 minutes, 12 seconds north latitude and 116 degrees, 23 minutes, 15 seconds west longitude; Avawatz Pass, Calif. 7.5 minute quadrangle; (UTM 11S, 0555534e 3930897n)

RANGE IN CHARACTERISTICS:

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

Soil temperature: 55 to 59 degrees F.
Organic matter: 0 to 0.5 percent
Surface rock fragments: 60 to 80 percent gravel, 0 to 10 percent cobbles and 0 to 5 percent stones

Control section:
Depth to bedrock: 4 to 10 inches

A horizon
Value: 3 or 4 moist

Chroma: 3 or 4, dry or moist

Clay content: 8 to 15 percent

Reaction: slightly or moderately alkaline

Bw horizon
Value: 5 or 6 dry, and 3 or 4 moist

Chroma: 3 or 4, dry or moist

Clay content: 8 to 15 percent

Structure: medium or coarse subangular blocky

Consistence: Soft to moderately hard

Reaction: Slightly or moderately alkaline

Other features: absent to common clay films on rock fragments


R horizon
Other features: many clay films on fractured rock faces

COMPETING SERIES: These are the Mizel (NV) series. Mizel soils have a MAST of 50 to 54 degrees F and average 40 to 60 percent rock fragments in the control section.

GEOGRAPHIC SETTING: Juratrias soils are on mountains. Slope ranges from 15 to 50 percent. The soils formed in residuum and colluvium from metamorphic material. Elevations are 3,900 to 5,900 feet. The climate is arid with warm, dry summers and cool, moist winters. The mean annual precipitation is 4 to 8 inches; mean annual air temperature is 54 to 57 degrees F., and the frost-free season is 200 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mulespring and Newera soils on similar landscape positions. Mulespring and Newera soils have argillic horizons. In addition, Mulespring soils are 14 to 20 inches deep to a paralithic contact.

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

USE AND VEGETATION: Juratrias soils are used for military exercises and wildlife habitat. The present vegetation is mainly blackbrush, spiny hopsage, Nevada ephedra, winterfat, Mojave yucca and desert needlegrass.

DISTRIBUTION AND EXTENT: Mojave Desert of southeastern California, confined to included areas of higher elevation in MLRA 30 with characteristics of MLRA 29. The soils are of small extent in MLRA 30.

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

SERIES PROPOSED: San Bernardino County, California, Fort Irwin Soil Survey Area, 1997. The name is from the Jura-Trias geologic period.

REMARKS: Diagnostic horizons and features recognized in the profile are:

1. Ochric epipedon -- 0 to 3 inches (A horizon)

Responsibility for this series was transferred from Davis to Phoenix 9/2015. The last revision to the series was 4/2000. ET

---

National Cooperative Soil Survey
U.S.A.