LOCATION BLACKPOINT AK
Established Series
SAS/MPS
02/2022
BLACKPOINT SERIES
Landscape--hills and mountains
Landform--hillslopes and mountain slopes
Slope--20 to 70 percent
Parent material--colluvium over residuum
Mean annual precipitation--about 300 mm
Mean annual air temperature--about -3 degrees C
Depth class--moderately deep to paralithic bedrock
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Coarse-loamy, isotic Typic Dystrocryepts
TYPICAL PEDON: Blackpoint silt loam on a south facing convex, linear backslope, on a slope of 55 percent at an elevation of 237 m (The soil was dry to 30 cm and moist throughout the rest of the profile when described on July 18, 2019.)
Oe--0 to 2 cm; moderately decomposed plant material, very dark brown (10YR 2/2) dry, black (10YR 2/1) moist; many very fine, fine, and medium roots; very strongly acid (pH 4.9); abrupt irregular boundary
A--2 to 8 cm; silt loam, very dark grayish brown (10YR 3/2) dry, very dark brown (10YR 2/2) moist; weak very fine granular structure; very friable, nonsticky, nonplastic; many very fine and fine roots; few very fine, fine, and medium irregular pores; very strongly acid (pH 5.0); abrupt irregular boundary
Bw1--8 to 17 cm; silt loam, dark yellowish brown (10YR 4/4) dry, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; very friable, nonsticky, nonplastic; many very fine and common fine roots; few very fin, fine, and medium irregular pores; 10 percent angular gravel; strongly acid (pH 5.3); clear irregular boundary
Bw2--17 to 32 cm; gravelly silt loam, brown (7.5YR 4/4) dry, very dark brown (7.5YR 2.5/2) moist; weak coarse granular structure; very friable, slightly sticky, moderately plastic; many very fine and few fine roots; common very fine irregular pores; 25 percent angular gravel; strongly acid (pH 5.3); clear smooth boundary
Bw3--32 to 85 cm; gravelly silt loam, 50 percent light yellowish brown (10YR 6/4) and 50 percent pale brown (10YR 6/3) dry, 50 percent dark yellowish brown (10YR 4/4) and 50 percent brown (10YR 4/3) moist; moderate thin platy structure; friable, slightly sticky, nonplastic; few very fine and fine roots; many very fine irregular pores; 3 percent medium dark yellowish brown (10YR 4/6), moist, masses of oxidized iron; 25 percent angular gravel; strongly acid (pH 5.4); gradual smooth boundary
Cr--85 cm; dark gray (5Y 4/1) dry, black (5Y 2/1) moist
TYPE LOCATION: Nome Census Area County, Alaska, latitude 63.2982415 longitude -160.8401253 degrees, datum WGS84 (Coordinates determined with a GPS unit)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--0 to 4 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October
Thickness of ochric epipedon--5 to 20 cm
Thickness of cambic horizon--35 to 90 cm
Particle Size Control Section:
*Clay--5 to 15 percent
*Total fragments--15 to 35 percent gravels
*Sodium fluoride pH--8.4 to 11.6
*Ratio of 1500 kPa water to measured clay--0.6 to 6.0
Oe horizon
Thickness--2 to 8 cm
A horizon
Hue--10YR or 7.5YR
Value--2 or 2.5 moist, 3 to 6 dry
Chroma--1 or 2
Fine-earth texture--silt, silt loam
Clay--2 to 10 percent
Sand--15 to 40 percent
Organic carbon--5 to 12 percent
Total rock fragment content--0 to 10 percent gravel
Reaction--4.7 to 5.4
Thickness-- 5 to 12 cm
Bw1 horizon
Hue--10YR or 7.5YR
Value--3 or 4 moist, 5 or 6 dry
Chroma--3 or 4
Clay--4 to 12 percent
Sand--15 to 40 percent
Organic carbon--1 to 3 percent
Total rock fragment content--10 to 30 percent gravel
Reaction--4.9 to 5.6
Thickness--5 to 15 cm
Bw2 horizon
Hue--7.5YR, 10YR, or 2.5Y
Value--2.5 to 4 moist, 4 to 6 dry
Chroma--2 to 4
Fine-earth texture--silt loam, sandy loam, loam
Clay--5 to 15 percent
Sand--20 to 55 percent
Organic carbon--2 to 3 percent
Total rock fragment content--15 to 35 percent gravel
Reaction--5.0 to 5.8
Thickness--10 to 20 cm
Bw3 horizon
Hue--10YR or 2.5YR
Value--3 or 4 moist, 5 or 6 dry
Chroma--3 or 4
Fine-earth texture--silt loam, sandy loam, loam
Clay--5 to 15 percent
Sand--25 to 55 percent
Organic carbon--1 to 2 percent
Total rock fragment content--15 to 35 percent gravel
Reaction--5.0 to 6.3
Thickness--20 to 45 cm
Cr horizon
COMPETING SERIES:
*
Tolukowuk--moderately deep to densic layer
GEOGRAPHIC SETTING:
*Elevation--50 to 550 m
*Climate--warm, moist summers; cold, dry winters
*Mean annual precipitation--400 to 550 mm
*Mean annual air temperature-- -5 to -1 degrees C
*Frost-free period--45 to 80 days
GEOGRAPHICALLY ASSOCIATED SOILS:
*
Paugna--very deep, umbric epipedon; shoulders and upper backslopes of mountains
*
Golsovia--very deep; side slopes and nose slopes of hills and escarpments
*MountMcDonald--shallow to lithic contact; shoulders and summits of mountains
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
*Drainage class--well drained
*Saturation during normal years--none
*Saturated hydraulic conductivity (Ksat)--high to moderately high throughout the profile
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential native vegetation--quaking aspen, white spruce, bluejoint, bunchberry dogwood, Barclay's willow, marsh Labrador tea, alpine azalea, bog blueberry, tealeaf willow, lingonberry, western oakfern, fireweed, cup lichen, greygreen reindeer lichen, moss, juniper polytrichum moss, black crowberry, stiff clubmoss, running clubmoss, star reindeer lichen, felt lichen, Schreber's big red stem moss, splendid feather moss, polytrichum moss
DISTRIBUTION AND EXTENT: Nulato Hills-Southern Seward Peninsula Highlands, Alaska; MLRA 240; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Nulato Hills BLM area, Nome Census Area, Alaska; 2021
REMARKS:
Diagnostic horizons and features recognized in this pedon
*Particle-size control section--zone from 27 to 85 cm
*Ochric epipedon--zone from 0 to 8 cm
*Cambic horizon--zone from 8 to 85 cm
*Paralithic contact--85 cm
National Cooperative Soil Survey
U.S.A.