LOCATION MARACK OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Calciargidic Argixerolls
TYPICAL PEDON: Marack gravelly silty clay loam - on a 3
percent convex slope, rangeland. (Colors are for dry soil
unless otherwise noted.)
A1--0 to 2 inches; grayish brown (10YR 5/2) gravelly
silty clay loam, very dark grayish brown (10YR 3/2) moist;
moderate medium granular structure; soft, friable, slightly
sticky and slightly plastic; many very fine and fine roots;
many very fine and fine continuous irregular pores; 25
percent gravel; neutral (pH 6.8); clear smooth boundary. (2
to 6 inches thick)
A2--2 to 12 inches; grayish brown (10YR 5/2) gravelly
silty clay loam, very dark grayish brown (10YR 3/2) moist;
moderate fine subangular blocky structure; soft, friable,
slightly sticky and slightly plastic; many very fine and
fine roots; many very fine and fine continuous tubular
pores; 20 percent gravel; neutral (pH 6.8); abrupt smooth
boundary. (8 to 14 inches thick)
Bt--12 to 17 inches; brown (10YR 5/3) clay, dark brown
(10YR 4/3) moist; strong coarse subangular blocky structure;
hard, firm, very sticky and very plastic; common very fine
and fine roots; many very fine and fine continuous tubular
pores; many thick clay films on face of peds and in pores;
neutral (pH 7.2); clear smooth boundary. (4 to 7 inches
thick)
Btk--17 to 25 inches; yellowish brown (10YR 5/4) silty
clay, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic;
common very fine and fine roots; common very fine and fine
continuous tubular pores; common moderately thick clay films
on peds and in pores; slightly effervescent with segregated
lime blotches; mildly alkaline (pH 7.6); clear smooth
boundary. (6 to 11 inches thick)
Bk--25 to 34 inches; light yellowish brown (10YR 6/4)
clay loam, yellowish brown (10YR 5/4) moist; moderate fine
and medium subangular blocky structure; slightly hard,
friable, slightly sticky and slightly plastic; common very
fine roots; few very fine continuous tubular pores; strongly effervescent with disseminated lime; moderately alkaline (pH
8.2); clear smooth boundary. (8 to 15 inches thick)
2Bk2--34 to 47 inches; very pale brown (10YR 7/3) very
gravelly loam, yellowish brown (10YR 5/4) moist; weak fine
subangular blocky structure; soft, friable, nonsticky and
nonplastic; few very fine roots; few very fine discontinuous
tubular pores; 40 percent gravel, strongly effervescent with disseminated lime; moderately alkaline (pH 8.4); abrupt wavy boundary. (10 to 18 inches thick)
3Crk--47 to 60 inches; consolidated tuffaceous
sediments; strongly effervescent with disseminated lime;
strongly alkaline (pH 8.6).
TYPE LOCATION: Baker County, Oregon; located 600 feet west
and 1,100 feet south of the NE corner of sec. 21, T. 13 S.,
R. 37 E.
RANGE IN CHARACTERISTICS: These soils are dry in all parts
of the moisture control section more than half the time
(cumulative) that the soil temperature is above 41 degrees
F. The mean annual soil temperature is 43 to 47 degrees F.
Depth to tuffaceous sediments is typically 40 to 60 inches,
but may be greater than 60 inches in some pedons. Depth to
the Bt horizon is 10 to 20 inches.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and
chroma of 1 or 2 moist and dry. It is gravelly or very
gravelly silty clay loam or silt loam. It has 0 to 40
percent gravel.
The Bt horizon has value of 5 or 6 dry, 3 or 4 moist and
chroma of 3 or 4 moist and dry. It is clay or silty clay,
averaging 40 to 50 percent clay. It has moderate to strong structure. It has 0 to 10 percent gravel.
The Bkt horizon has value of 5 or 6 dry, 3 or 4 moist and
chroma of 3 or 4 moist and dry. It has 0 to 10 percent
gravel. It is slightly to strongly effervescent, with a
lime content that ranges from segregated blotches to
complete dissemination.
The Bk1 horizon has value of 6 or 7 dry, 5 to 6 moist and
chroma of 3 or 4 moist and dry. It is clay loam or silty
clay loam. It has 0 to 15 percent gravel. It is strongly
to violently effervescent with disseminated lime.
The 2Bk2 horizon has value of 6 or 7 dry, 4 through 6 moist
and chroma of 3 or 4 moist and dry. It is very gravelly
loam, sandy loam or silt loam, with 0 to 40 percent gravel
and 0 to 10 percent cobbles. It is strongly to violently effervescent with disseminated lime.
COMPETING SERIES: This is the
Ramires series. Ramires
soils have a lithic contact at 24 to 40 inches.
GEOGRAPHIC SETTING: The Marack soils are on old terraces.
Slopes are 2 to 35 percent. Elevations range from 3,800 to
4,400 feet. The soils formed in lacustrine sediments. The
mean annual precipitation is 9 to 12 inches. The mean
annual temperature is 40 to 45 degrees F. The frost-free
period is 60 to 90 days. This soil is on the Dolph
geomorphic surface.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Burntriver,
Campcreek,
Rastus,
Skullgulch, and
Wahstal soils. The
Burntriver soils have a Bw horizon averaging 35 to 40
percent clay and are located on adjacent lower terraces and
fans. Campcreek and Skullgulch soils have 2Bt horizons,
averaging 50 to 60 percent clay and occur on adjacent higher terraces. Rastus soils are moderately deep to a duripan and
occur on adjacent higher terraces. Wahstal soils are
shallow to a duripan and occur on adjacent higher terraces.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow to
medium. Permeability is slow.
USE AND VEGETATION: These soils are used for rangeland.
The native vegetation is Idaho fescue, bluebunch wheatgrass,
Mountain big sagebrush, basin big sagebrush, and prairie
junegrass.
DISTRIBUTION AND EXTENT: Eastern Oregon. The series is of
small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Baker County Area, Oregon; 1988.
REMARKS: Diagnostic horizons and features in this pedon
are:
Mollic epipedon - the zone from the surface of the soil to a
depth of 12 inches (A1, A2 horizons).
Argillic horizon - the zone from 12 inches to 25 inches (Bt,
Btk horizons).
Calcic horizon - the zone from 17 to 47 inches (Btk, Bk1,
2Bk2 horizons).