LOCATION MICAPEAK                WA+ID

Established Series
Rev. SMM-BDG-RJS
04/2017

MICAPEAK SERIES

The Micapeak series consists of moderately deep, well drained soils on mountain and foothill slopes. They formed in colluvium and residuum weathered from granite, gneiss, and schist with minor amounts of loess and volcanic ash in the upper part. Slope ranges from 5 to 65 percent. The mean annual precipitation is about 625 mm, and the mean annual air temperature is about 6.7 degrees C.

TAXONOMIC CLASS: Coarse-loamy, isotic, frigid Vitrandic Haploxerepts

TYPICAL PEDON: Micapeak gravelly ashy loam, timbered; on a northwest-facing slope of 36 percent at 1,005 meters elevation. When described on October 13, 1998, the soil was dry. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)

Oi--0 to 2 cm; slightly decomposed needles, twigs, leaves, and cones.

Oe--2 to 3 cm; moderately decomposed organic matter mixed with discontinuous minor amounts of St Helens Volcanic ash.

A--3 to 18 cm; grayish brown (10YR 5/2) gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine and common medium roots; many very fine and fine irregular and tubular pores; 5 percent fine mica flakes; 15 percent gravel; slightly acid (pH 6.5); clear irregular boundary. (8 to 18 cm thick)

Bw1--18 to 33 cm; light yellowish brown (10YR 6/4) gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and few medium and coarse roots; many very fine and fine irregular and few medium tubular pores; 10 percent fine mica flakes; 25 percent gravel; slightly acid (pH 6.3); gradual wavy boundary.

Bw2--33 to 56 cm; light yellowish brown (10YR 6/4) gravelly loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium and coarse roots; many very fine irregular and common very fine and fine tubular pores; 15 percent fine mica flakes; 20 percent gravel; moderately acid (pH 6.0); clear wavy boundary. (combined thickness of Bw horizons -- 18 to 41 cm)

BCt--56 to 84 cm; light yellowish brown (10YR 6/4) gravelly loam, dark yellowish brown (10YR 4/4) moist; weak medium and coarse angular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, fine and few medium and coarse roots; common very fine irregular pores and few fine tubular pores; 15 percent fine mica flakes; 1 discontinuous wavy band of dark yellowish brown (10YR 4/6) moist loam in the lower part of the horizon that is .1 to .25 inch thick, with few thin discontinuous clay films bridging sand grains and on faces of peds; 10 percent paragravel and 20 percent gravel; moderately acid (pH 6.0); clear wavy boundary. (10 to 28 cm thick)

C--84 to 99 cm; very pale brown (10YR 7/4) gravelly sandy loam, yellowish brown (10YR 5/4) moist; massive; hard, friable, nonsticky and slightly plastic; few very fine, fine and medium roots; many very fine irregular pores and few fine tubular pores; 15 percent fine mica flakes; pockets of material containing 50 percent fine mica flakes comprising about 5 percent of the horizon; 15 percent paragravel and 15 percent gravel; moderately acid (pH 5.8); abrupt wavy boundary. (0 to 15 cm thick)

Cr--99 cm; weathered micaceous gneiss and schist bedrock, no roots, can be dug with a spade with moderate difficulty, rock structure is clearly visible.

TYPE LOCATION: Spokane County, WA; about 1.5 miles west of Mica Peak and .75 mile south of Belmont Road; about 560 meters east and 450 meters north of the southwest corner of section 16, T. 24 N., R. 45 E.; USGS Micapeak, Wash. Topographic quadrangle. (Latitude 47 degrees, 34 minutes, 10.3 seconds N. and Longitude 117 degrees, 7 minutes, 27.5 seconds W.) NAD83.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature -- 6.7 to 7.8 degrees C.
Moisture control section -- dry in all parts between 20 and 60 cm, 60 to 75 days after the summer solstice, July to September, moist October through June
Depth to weathered bedrock -- 50 to 100 cm
Depth to hard bedrock -- 100 to more than 150 cm
Thin recent (1980) volcanic ash layer -- 1 to 2 cm thick present in some pedons between the organic and mineral soil surface

Volcanic ash influence -- 20 to 36 cm thick
Estimated properties of the volcanic ash influenced layers:
Volcanic glass content -- 5 to 20 percent
Acid oxalate Al + 1/2 Fe -- 0.4 to 1.0 percent
Moist bulk density -- 1.1 to 1.35 g/cc
15 bar water retention -- 5 to 10 percent on air-dried samples
Clay content -- 5 to 12 percent in the particle-size control section
Mica content -- 2 to 15 percent

A horizon
Value: 4 to 7 dry; 2 to 5 moist
Chroma: 2 or 3 dry or moist
Texture (less than 2 mm fraction): ashy silt loam or ashy loam
Gravel: 0 to 25 percent
Reaction: moderately acid or slightly acid

Bw1 horizon
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 3 or 4 dry or moist
Texture (less than 2 mm fraction): ashy loam, ashy silt loam or loam
Rock fragments: 0 to 25 percent gravel
Reaction: slightly acid or moderately acid

Bw2, BCt, BC horizons
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 3 or 4 dry or moist
Texture (less than 2 mm fraction): loam, sandy loam or coarse sandy loam
Clay content - 5 to 12 percent
Gravel content - 10 to 30 percent
Paragravel content - 0 to 10 percent
Reaction - moderately acid or slightly acid

C horizon
Hue: 10YR or 2.5Y dry or moist
Value: 5 to 8 dry; 4 to 7 moist
Chroma: 3 or 4 dry or moist
Texture (less than 2 mm fraction): sandy loam or coarse sandy loam
Clay content: 5 to 12 percent
Rock fragments: 10 to 40 percent gravel
Parafragments: 0 to 20 percent paragravel
Mica content: 2 to 15 percent
Reaction: moderately acid or slightly acid
Note: Total gravel and paragravel content averages 40 percent or less.

COMPETING SERIES:
Ardenmont soils: are deep to paralithic contact
Cobbler soils: are very deep
Downeygulch soils: are moderately deep to lithic contact
Enson soils: are moderately deep to a densic contact
Green Bluff soils: are very deep
Labuck soils: does not have mica in the subsoil and averages 12 to 18 percent clay in the particle-size control section.
Quinnamose soils: are deep to a paralithic contact
Stapaloop soils: are very deep

GEOGRAPHIC SETTING: Micapeak soils are on side slopes, ridges and structural benches of mountains and foothills at elevations of 600 to 1,280 meters. They formed in colluvium and residuum weathered from granite, gneiss, and schist with minor amounts of loess and volcanic ash in the upper part. The climate is characterized by cold, wet winters and warm, dry summers. Slopes are 5 to 65 percent. The mean annual precipitation is 500 to 900 mm. The mean annual temperature is 5.6 to 7.2 degrees C. The frost-free period is 80 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kramerhill, Kruse, Quinnamose, and Spokane soils. Kramerhill soils are mesic, deep to a paralithic contact, have fine-loamy argillic horizons and are on convex backslopes of foothills. Kruse soils have fine-loamy argillic horizons, are very deep, and are on linear backslopes of foothills. Quinnamose soils are frigid, are deep to a paralithic contact, and are on mountain and foothill slopes. Spokane soils are mesic, are moderately deep to a paralithic contact, and are on convex backslopes of foothills.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Micapeak soils are used for timber production, wildlife habitat, watershed, and recreation. Potential natural vegetation is mainly Douglas-fir, ponderosa pine, and lodgepole pine, with an understory of mallow ninebark, creambush oceanspray, baldhip rose, pine grass, Saskatoon serviceberry, common snowberry, white spirea, and low Oregon grape.

DISTRIBUTION AND EXTENT: Northeastern Washington, and northern Idaho; MLRA 43A and 44A. Series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Spokane County, WA, 2012

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon -- the zone from 0 to 18 cm (Oi, Oe, A horizons)
Cambic horizon -- the zone from 18 to 84 cm (Bw1, Bw2, BCt horizons)
Vitrandic feature -- the zone from 3 to 33 cm (A, Bw1 horizons)
Paralithic contact -- the zone beginning at 99 cm (Cr horizon)
Particle-size control section -- the zone from 28 to 99 cm (part of the Bw1, Bw2, BCt, C horizons)

This series is correlated to the PSME/PHMA habitat type.

Significant areas of Micapeak soils were previously mapped as Moscow series in Spokane County.

This series has been reclassified (11/2006) from Coarse-loamy, isotic, frigid Vitrandic Dystroxerepts to Coarse-loamy, isotic, frigid Vitrandic Haploxerepts based on lab data collected in Spokane County, WA.

Further review is needed to determine differences in volcanic ash influence and mica content in Micapeak soils compared to the similar Labuck series.

ADDITIONAL DATA: Laboratory data available for Soil Survey Sample Number: S01WA-063-006 Spokane County, Washington. NSSL Pedon Number: 02N0117.

---

National Cooperative Soil Survey
U.S.A.