LOCATION THETIS WATentative Series
TAXONOMIC CLASS: Ashy-skeletal, amorphic Andic Haplocryods
TYPICAL PEDON: Thetis gravelly sandy loam - under a coniferous forest on a 62 percent northeast facing slope at an elevation of 2920 feet. The soil was dry when described. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
0e--2 to 0 inch; partially decomposed forest litter; abrupt wavy boundary. (1 to 3 inches thick)
E--0 to 4 inches; light brownish gray (10YR 6/2) loamy sand, (volcanic ash) dark grayish brown (10YR 4/2) moist; massive; soft, very friable, nonsticky, nonplastic; few very fine roots; common very fine tubular pores; 5 percent pebbles; strongly acid (pH 5.2); abrupt wavy boundary. (0 to 4 inches thick)
Bs1--4 to 7 inches; yellowish brown (10YR 5/4) gravelly sandy loam, dark yellowish brown (10YR 4/4) and dark grayish brown (10YR 4/2) moist; weak coarse granular structure; soft, very friable, nonsticky, nonplastic, weakly smeary; common very fine roots; many very fine irregular pores; few dark yellowish brown (10YR 4/6) moist iron concretion, 1 to 2 mm in diameter; (10 percent light brownish gray (10YR 6/2) volcanic ash mixed throughout horizon) 30 percent pebbles; NaF pH 11.4; strongly acid (pH 5.4); abrupt wavy boundary. (2 to 4 inches thick)
2kBs2--7 to 10 inches; brown (7.5YR 4/4) gravelly sandy loam, dark brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; common very fine roots, common very fine tubular pores; few dark yellowish brown (10YR 4/6) moist iron concretion 1 to 2 mm in diameter; 30 percent pebbles; NaF pH 10.5; medium acid (pH 5.6); abrupt wavy boundary. (3 to 6 inches thick)
2Bw--10 to 20 inches; light yellowish brown (10YR 6/4) very gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; common very fine roots, common very fine tubular pores; 45 percent pebbles, 5 percent cobbles; NaF pH 10.5; strongly acid (pH 5.4); clear wavy boundary. (6 to 10 inches thick)
2BC--20 to 46 inches; light yellowish brown (10YR 6/4) very gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak coarse subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; few medium and fine roots; few fine tubular pores; 30 percent pebbles, 10 percent cobbles; NaF pH 10.5; medium acid (pH 5.6); clear wavy boundary. (12 to 26 inches thick)
2C--46 to 60 inches; pale yellow (2.5Y 7/4) very gravelly sandy loam, olive brown (2.5Y 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; very few very fine roots; many very fine irregular pores; 30 percent pebbles, 10 percent cobbles; NaF pH 10.6; medium acid (pH 5.8).
TYPE LOCATION: Kittitas County, Washington; about 3 miles northwest of Easton; 1,330 feet south and 2,280 feet west of the northeast corner sec. 29, T. 21 N., R. 13 E., W.M.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 44 to 46 degrees F. Except for bulk density, the exchange complex is dominated by amorphous material in the particle-size control section. Solum thickness is 28 to 50 inches. The spodic horizon thickness is 5 to 10 inches. The soils are usually moist but are dry in all parts of the moisture control section for 15 to 30 days. The particle-size control section averages 35 to 60 percent rounded rock fragments of mixed lithology. Reaction is strongly acid or medium acid throughout.
The E horizon has a hue of 7.5YR or 10YR, value of 3 or 4 moist, chroma of 2 or 3 dry and 1, 2 or 3 moist.
The Bs horizon has a hue of 7.5YR or 10YR, value of 4 or 5 dry, 3, 4 or 5 moist, chroma of 2 or 4 moist.
The 2Bw and 2BC horizons have a hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 or 4 moist chroma of 4 or 6 moist. They are very gravelly sandy loam, very cobbly sandy loam or extremely cobbly sandy loam.
The 2C horizon has a hue of 2.5Y or 10YR, value of 5 or 6 dry, 4, 5 or 6 moist and chroma of 2, 3, or 4 dry and moist. It is very gravelly, sandy loam, very cobbly sandy loam or extremely cobbly sandy loam.
COMPETING SERIES: These are the Alkiridge, Crinker, Elsnor, Esmeralda, Fears, Gilpar, Hatchet, Howson, Kachess, Kindy, Lemah, Ohana, Playco, Polallie, Springsteen, Vabus and Waptus soils. Alkiridge, Kindy, Ohana, Vabus and Waptus soils have a paralithic contact with dense glacial till at 20 to 40 inches. Crinker, Hatchet, Howson, Klawatti, Polallie, and Springsteen soils have a lithic contact at 20 to 40 inches. Elsnor soils have a solum thickness of 8 to 26 inches and are dry 30 to 45 days in the moisture control section. Esmeralda soils have 40 to 70 percent diabase, gabbro, and serpentinized basalt rock fragments in the particle-size control section, have a mean annual soil temperature of 40 to 42 degrees F and are dry 30 to 45 days in the moisture control section. Gilpar soils have 45 to 60 percent angular andesite, basalt and pyroclastic rock fragments in the particle size control section and are dry 30 to 45 days in the moisture control section. Kachess soils are very gravelly loam or very cobbly loam in the 2Bw horizon, have a massive 3C horizon and are dry 30 to 45 days in the moisture control section. Lemah soils have a spodic horizon 1 to 3 inches thick and average 35 to 70 percent sandstone fragments in the particle-size control section. Playco soils have a volcanic ash mantle more than 12 inches thick.
GEOGRAPHIC SETTING: Thetis soils are on mountainsides and have slopes of 25 to 65 percent. These soils formed in loose glacial till with addition of volcanic ash. Elevation is 2,400 to 4,000 feet. These soils are in a marine influenced climate with cool, dry summers and cool, moist winters. The average annual precipitation is 65 to 80 inches. The mean January temperature is about 26 degrees F and the mean July temperature is about 51 degrees F. The mean annual temperature is about 43 degrees F. The growing season at 28 degrees F is 130 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Gilpar, Kachess, and Vabus soils.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; permeability is moderately rapid.
USE AND VEGETATION: Used for woodland, wildlife habitat, and watershed. Vegetation is Douglas-fir, western hemlock and Pacific silver fir with an understory of huckleberry, pachystima, Oregon-grape, princes pine, pyrola, western rattlesnake plantain, and common beargrass.
DISTRIBUTION AND EXTENT: East slopes of the Cascade Mountains in western Kittitas County. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Kittitas County, Washington, 1981.
REMARKS: Partial laboratory data are available, National Soil Survey Laboratory samples numbered 801615, 801616 and 801617. Diagnostic horizons and features recognized in this pedon are an albic horizon from the mineral surface to 4 inches and a spodic horizon from 4 to 10 inches.