LOCATION MARMOTHILL CA+NV
Established Series
Rev. AMB-EWB-TM-JVC
04/2017
MARMOTHILL SERIES
The Marmothill series consists of very deep, well drained soils that formed in colluvium and residuum derived from altered volcanic rocks with surficial additions of eolian volcanic ash. Marmothill soils are on hills, mountains and plateaus. Slopes are 4 to 30 percent. The mean annual precipitation is about 380 mm and the mean annual temperature is about 6 degrees C.
TAXONOMIC CLASS: Ashy-skeletal over clayey, glassy over smectitic, frigid Vertic Palexerolls
TYPICAL PEDON: Marmothill very gravelly ashy fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 60 percent gravel, 10 percent cobbles, and 5 percent stones.
A1--0 to 5 cm; brown (10YR 5/3) very gravelly ashy fine sandy loam, dark brown (10YR 3/3) moist; weak thick platy structure parting to weak medium subangular blocky; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; common very fine vesicular and few very fine tubular and many very fine interstitial pores; 40 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (3 to 8 cm thick)
A2--5 to 12 cm; brown (10YR 5/3) gravelly ashy loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common fine roots and many very fine roots; common very fine tubular and interstitial pores; 10 percent cobbles and 15 percent gravel; slightly acid (pH 6.3); clear wavy boundary. (3 to 10 cm thick)
Bt--12 to 25 cm; brown (10YR 5/3) very gravelly ashy loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common fine roots and many very fine roots; common very fine and fine tubular and common very fine interstitial pores; 10 percent faint clay bridges between sand grains; 40 percent gravel; neutral (pH 7.1); abrupt wavy boundary. (13 to 18 cm thick)
2Btss--25 to 56 cm; brown (7.5YR 5/4) clay, brown (7.5YR 4/4) crushed and moist; strong fine prismatic structure parting to strong fine and medium angular blocky; extremely hard, very firm, very sticky and very plastic; few fine and medium roots in vertical cracks and common very fine roots; common very fine tubular pores; common prominent pressure cutans on faces of peds and 5 percent faint slickensides; 5 percent cobbles and 5 percent gravel; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 31 cm thick)
2Btky1--56 to 71 cm; brown (7.5YR 5/4) cobbly clay, strong brown (7.5YR 4/6) moist; weak medium prismatic structure parting to strong thin platy; very hard, friable, very sticky and very plastic; few fine and medium roots in vertical cracks and common very fine roots; few very fine tubular and common very fine interstitial pores; 50 percent distinct clay films lining pores and 50 percent distinct clay films on faces of peds; secondary carbonates segregated as 25 percent fine to coarse masses; 1 percent fine masses of gypsum crystals; 15 percent cobbles and 15 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (15 to 25 cm thick)
2Btky2--71 to 91 cm; brown (7.5YR 5/4) gravelly clay, strong brown (7.5YR 4/6) moist; moderate fine and medium angular blocky structure; very hard, friable, very sticky and very plastic; few very fine roots; common very fine interstitial and few very fine tubular pores; 50 percent distinct clay films on faces of peds and 50 percent distinct clay films lining pores; 15 percent manganese masses; secondary carbonates segregated as 10 percent fine and medium masses; 1 percent fine masses of gypsum crystals; 5 percent cobbles and 15 percent gravel; slightly effervescent; moderately alkaline (pH 8.1); clear wavy boundary. (16 to 25 cm thick)
2Btky3--91 to 127 cm; brown (7.5YR 5/4) gravelly clay, strong brown (7.5YR 4/6) moist; moderate fine and medium angular blocky structure; very hard, friable, very sticky and very plastic; few very fine roots; common very fine interstitial and few very fine tubular pores; 50 percent distinct clay films on faces of peds and 50 percent distinct clay films lining pores; 15 percent manganese masses; secondary carbonates segregated as 2 percent fine and medium masses; 2 percent fine masses of gypsum crystals; 5 percent cobbles and 15 percent gravel; noneffervescent matrix; moderately alkaline (pH 8.2); clear wavy boundary. (20 to 38 cm thick)
2Btk--127 to 152 cm; brown (7.5YR 5/4) gravelly clay, strong brown (7.5YR 4/6) moist; moderate fine and medium angular blocky structure; very hard, friable, very sticky and very plastic; few very fine roots; common very fine interstitial and few very fine tubular pores; 50 percent distinct clay films on faces of peds and 50 percent distinct clay films lining pores; secondary carbonates segregated as 1 percent masses in the matrix and 1 millimeter thick coats on bottoms of rock fragments; 5 percent cobbles and 10 percent gravel; noneffervescent matrix; moderately alkaline (pH 8.2).
TYPE LOCATION: Mono County, California; in the Bodie Hills about 305 meters southeast of the Paramount Mine; in a nonsectionized township; USGS Dome Hill 7.5 minute topographic quadrangle; latitude 38 degrees 16 minutes 29.7 seconds N and longitude 119 degrees 03 minutes 00.6 seconds W; WGS84 38.27492 latitude, -119.05017 longitude.
RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section during winter and spring; usually dry from July through early October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 25 to 36 cm; includes the Bt horizon.
Depth to major lithologic discontinuity: 19 to 36 cm.
Depth to identifiable secondary carbonates and gypsum: 50 to 100 cm.
Linear extensibility (LE): 6 to 9 cm.
Other features - There is normally an abrupt horizon boundary between the Bt and 2Btss horizons with a clay increase of 25 percent or more (absolute) within one inch of the boundary.
Particle-size control section - Clay content: 18 to 27 percent in the upper part and 40 to 55 percent in the strongly contrasting lower part.
Rock fragments: Averages 35 to 50 percent in the upper part and less than 25 percent in the strongly contrasting lower part, mainly gravel. Lithology of rock fragments is mainly altered rhyolite and andesite.
A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 40 to 60 percent in the very fine sand and fine sand fractions.
Bt horizon
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly ashy loam or very gravelly ashy sandy loam.
Clay content: 18 to 27 percent.
Rock fragments: 35 to 50 percent.
Organic matter content: 1 or 2 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 30 to 50 percent in the very fine sand and fine sand fractions.
2Btss horizon
Hue: 7.5YR or 10YR.
Value: 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Clay or gravelly clay.
Clay content: 40 to 55 percent.
Rock fragments: 10 to 25 percent, mainly gravel.
Reaction: Neutral through moderately alkaline.
Slickensides and other vertic features: Few slickensides are present in some pedons; most pedons have pressure cutans and narrow vertical cracks.
2Btky horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4 dry, 3 through 6 moist.
Texture: Gravelly clay or cobbly clay.
Clay content: 40 to 55 percent.
Rock fragments: 15 to 35 percent.
Reaction: Slightly alkaline or moderately alkaline.
Calcium carbonate equivalent: 0 to 2 percent.
Effervescence: Noneffervescent or slightly effervescent.
Identifiable secondary carbonates: Few to common, fine to coarse coats on bottoms of rock fragments or few to common masses in the matrix.
Secondary gypsum: Few fine to medium masses of crystals in the matrix.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Marmothill soils are on hills, mountains and plateaus. They formed in colluvium and residuum derived from altered volcanic rocks with surficial additions of eolian volcanic ash. The probable sources of the volcanic ash are the Mono Craters and Long Valley Caldera in eastern California. Slopes are 0 to 30 percent. Elevations range from 2,475 to 2,800 meters. The climate is semiarid with cold, moist winters and warm, dry summers. The majority of the precipitation occurs as snow, much of which is removed from the surface of the soil through wind action. This removal of snow greatly reduces the effective precipitation on this soil relative to surrounding non-convex areas. The mean annual precipitation is 350 to 460 mm, the mean annual temperature is 6 to 7 degrees C., and the frost-free period is 30 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Ashflat and
Vetash soils. Ashflat and Vetash soils have less than 27 percent clay and have more than 35 percent rock fragments throughout the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; very slow permeability; moderately low saturated hydraulic conductivity.
USE AND VEGETATION: Marmothill soils are used for livestock grazing, recreation, watershed, and wildlife habitat. The native vegetation is mainly low sagebrush, pine needlegrass, and bluegrass.
DISTRIBUTION AND EXTENT: Eastern California and western Nevada, in the western part of the Great Basin. These soils are not extensive. MLRA 26.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Mono County (Coleville-Bridgeport Area), California, 2010.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 25 cm (A1, A2, and Bt horizons).
Argillic horizon - The zone from 12 to 152 cm (Bt, 2Btss, 2Btky1, 2Btky2, 2Btky3, and 2Btk horizons).
Vertic subgroup feature - A linear extensibility of 6 cm or more between the soil surface and 100 cm.
Palexerolls great group feature - No clay decrease of 20 percent or more from the maximum clay content in the lower part of the argillic horizon (Bt, 2Btss, 2Btky1, 2Btky2, 2Btky3, and 2Btk horizons).
Slickensides - The zone from 25 to 56 cm (2Btss horizon).
Identifiable secondary carbonates - The zone from 56 to 152 cm (2Btky1, 2Btky2, 2Btky3, and 2Btk horizons).
Major lithologic discontinuity - The abrupt change to clayey material at 25 cm (between the Bt and 2Btss horizons).
Particle-size control section - The zone from 12 to 100 cm (Bt, 2Btss, 2Btky1, and 2Btky2 horizons and part of the 2Btky3 horizon).
Note: The upper part of the particle-size control section (the Bt horizon from 12 to 25 cm) has more than 35 percent by volume rock fragments. This series would classify in a strongly contrasting particle-size class of ashy-skeletal over clayey if it was present in the Keys to Soil Taxonomy.
ADDITIONAL DATA: Volcanic glass content in the A1, A2, and Bt horizons was determined locally by optical grain counts using a polarizing petrographic microscope. Observed glass contents in these horizons are 57, 51, and 42 percent in the fine sand fractions, respectively.
Classification was changed 3/2017 from Ashy over clayey, glassy over smectitic, frigid Vertic Palexerolls to Ashy-skeletal over clayey, glassy over smectitic, frigid Vertic Palexerolls.
User Pedon ID: 2007CA051005
National Cooperative Soil Survey
U.S.A.