LOCATION TERLINGUA               TX

Established Series
Rev. RAC/JLR/ACT/LEL
10/2012

TERLINGUA SERIES

The Terlingua series consists of very shallow, and shallow well drained, moderately permeable, gravelly soils that formed over igneous rock. These soils are on gently sloping to steep hills, mountains and fan remnants. Slopes range from 2 to 65 percent. The mean annual precipitation is about 9 inches and the mean annual air temperature is about 64 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, calcareous, hyperthermic Lithic Ustic Torriorthents

TYPICAL PEDON: Terlingua very gravelly coarse sandy loam--rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 2 inches; brown (10YR 5/3) very gravelly coarse sandy loam; dark brown (10YR 3/3) moist; weak medium granular structure; soft, very friable; few fine roots; 40 percent igneous gravel; slightly effervescent; slightly alkaline; clear smooth boundary.

Bk--2 to 4 inches; pale brown (10YR 6/3) very gravelly loam; brown (10YR 4/3) moist; moderate medium granular structure; slightly hard, friable; common fine roots; few fine pores; discontinuous coatings of calcium carbonates on some coarse fragments; 40 percent igneous gravel; slightly effervescent; slightly alkaline; clear wavy boundary.

Bk/Cr--4 to 11 inches; pale brown (10YR 6/3) extremely gravelly loam; brown (10YR 4/3) moist; moderate medium granular structure; slightly hard, friable; few fine roots; calcium carbonate coatings on coarse fragments; 80 percent igneous gravel and 1 percent igneous cobbles; slightly effervescent; moderately alkaline; abrupt wavy boundary.

Cr--11 to 13 inches; weathered igneous bedrock.

R--13 to 23 inches; hard igneous bedrock.

TYPE LOCATION: Brewster County, Texas; from the intersection of Texas Highway 118 and FM 170 in Study Butte, 11.9 miles east on Texas Highway 118 to Ross Maxwell Scenic Dr, 20.1 mile south, Left on ranch road 4.3 miles, left on River Rd W 2.5 miles, 250 feet south-southwest in rangeland. Smokey Creek Texas USGS topographic quadrangle; UTM coordinates: 651381 m E, 3218657 m N Zone 13.

RANGE IN CHARACTERISTICS:

Soil moisture: Ustic aridic soil moisture regime. Receives precipitation in all months. Driest period is November through April with peak rainfall occurring during May through October.

Soil temperature: 72 to 78 degrees F.

Depth to igneous bedrock: 4 to 20 inches

Clay content: 5 to 20 percent

Texture: coarse sandy loam, sandy loam, loam, fine sandy loam

Coarse fragments: mostly igneous material and range from 35 to 70 percent. Of the coarse fragments, 50 to 100 percent are gravel, 0 to 30 percent are stones, and 0 to 40 percent are cobbles

Surface cover: igneous gravel, cobbles, stones, and boulders cover 50 to 80 percent of the soil surface

A and Bk horizons
Hue: 7.5YR, 10YR
Value: 4 to 7 dry, 3 to 6 moist
Chroma: 2 to 4, dry or moist

The Bk and Cr horizons have calcium carbonate accumulations on coarse fragments and in seams.

Calcium carbonate equivalent: 1 to 20 percent

The R layer has a hardness of 3 to about 4 on Moh's scale

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Terlingua soils are on ridges and side slopes of igneous hills and mountains. Slopes are mostly 5 to 25 percent but range from 2 to about 65 percent. Rock outcrops and boulders are common in these areas. These soils are formed over intrusive and extrusive igneous rock, probably andesite and basalt, having gas voids. Mean annual precipitation is 10 to 13 inches with summer maximums. Mean annual air temperature ranges from 68 to 76 degrees F. Frost-free period ranges from 220 to 280, and elevation is 1,800 to 4,445 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Corazones, Studybutte, Blackgap, Mariscal, and Strawhouse series. Coranzones soils are deep and formed in slightly lower and similar positions in gravelly outwash valley fill. Studybutte soils are shallow to bedrock. Blackgap and Mariscal soils are shallow to limestone bedrock. Strawhouse soils have a petrocalcic horizon.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately rapid. Runoff is vertry low on 2 to 5 percent slopes, low on 5 to 20 percent slopes, and medium on slopes greater than 20 percent.

USE AND VEGETATION: Used mostly for livestock grazing and wildlife habitat. The present sparse vegetation is mostly whitethorn, lechuguilla, creosotebush, skeletonleaf goldeneye, pricklypear and scattered grass clumps of chino grama, threeawn, fluffgrass, and slim tridens.

DISTRIBUTION AND EXTENT: West Texas. MLRA 42. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Brewster County, Texas, 1982

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

Ochric epipedon - the zone from 0 to 4 inches (A horizon)

Entisol feature - the absence of diagnostic subsurface horizons

Fracture interval is too close for paralithic contact

Lithic contact: 16 inches; the upper boundary of R layer

The igneous bedrock material from which these soils are formed is neutral or slightly acid, and at the type location, weakly magnetic. Carbonates are from secondary sources, probably eolian materials.

Soil temperature regime classification changed from thermic to hyperthermic based on the summary of a 6-year soil temperature study in Far West Texas.

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy Eleventh Edition, 2010.

Moisture and temperature regime revised for TX622, Brewster County, TX, Main Part recorrelation, 11/2007, CEM

Type location was moved to better represent the series concept, January 2008

Revised for the correlation of Big Bend National Park, TX, Oct. 2010, CEM

Revised for the correlation of Hudspeth County, Texas (Main Part) and Culberson County, Texas (Main Part); July, 2012, NMS

Revised for the correlation of Presidio County, Texas ; Oct, 2012, WWJ

ADDITIONAL DATA: TAES Characterization data from one pedon in Big Bend National Park; No. S80TX-043-012.

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National Cooperative Soil Survey
U.S.A.