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GUNNISON AREA, COLORADO
<br />slopes; SEl/4 sec. 36, T. 47 N., R. 6 W., Gunnison
<br />County:
<br />Ol-~ inches to 1 inch, organic materiel consisting of bark,
<br />twigs, leaves, and needles.
<br />O7r] inch to 0, partly decomposed organic material.
<br />A2-0 to 8 inches, pinkish-gray (7.55'R 7/2) loam, brown
<br />(7.5YR 5/2) moist; weak, medium, subangular
<br />blocky structure parting to moderate, fine, gran-
<br />ular: weak platy structure in places; soft, very
<br />friable; 5 percent gravel end stones; pH 7.0; clear,
<br />smooth boundary.
<br />A6.B-R to 16 inches, mixed-colored, including pinkish-gray
<br />(7.5YR 7/2) and brown (7.5YR 5/3), heavy loam,
<br />brown (7.5YR 5/2) and dark brown (7.5YR 4/3)
<br />moist; moderate, medium, subangular blocky struc-
<br />ture parting to moderate, fine, granular; slightly
<br />hard, very friable; seams end nodules of R2t ma-
<br />terial imbedded in A2 matrix; 10 percent stones
<br />end gravel; pH 6.8; gradual, irregular boundary.
<br />B2t~16 to 34 inches, reddish-brown (51•R 5/3) clay loam,
<br />reddish brown (55•R 4/3) moist; moderate, me-
<br />dium, subangular blocky structure; hard, friable;
<br />thin nearly continuous clay films on pad tacos; ]U
<br />percent nc~olite rock, stones, and gravel; pH 6.6;
<br />clear, wavy boundary.
<br />R-34 Lo 60 inches, rhyolite.
<br />The A horizon is typically loam, but in places is gravelly
<br />and stony Inam.. The A2 horizon ranges from G to 12 inches
<br />in thickness end from pinkish gray to pink or light gray to
<br />very pale brown in color. The B2t horizon ranges from red-
<br />dish brown to light reddish brown. The soil is slightly acid
<br />or neutral. The content of angular gravel and stones ranges
<br />from 5 to 35 percent. Depth to bedrock ranges trom 20 to 40
<br />inches.
<br />Shute :md Sapinero loamy, 10 to :i0 percent slopes (Ssf~.
<br />-This mapping unit is mainly in the Blue D4esa and
<br />Pine Creek parts of the purvey area. It is about 65
<br />percent Shute loam and 20 percent Saninero loam. Each
<br />soil has [he profile described as typical of its series.
<br />The moderately sloping Shute soil is mostly on mound
<br />tainsides. The Sapinero soil is mostly on ridges.
<br />Included with these soils in mapping are areas of
<br />Youman and Sunshine soils in s~7all parks and clearing,
<br />and small areas of Vulcan soils on the east side of Pine
<br />Creek. These inclusions make up less than ]5 percent
<br />of the total acreage.
<br />This unit is almost entirely forested, mainly Engel-
<br />mann spruce and subalpine fir. Areas where forest fire
<br />and logging have been extensive are dominantly in
<br />stands of aspen anti scattered conifers.
<br />in this unit rmtoff is mrdium to rapid, and the erosion
<br />hazard is moderate to high. Use anti mana}[ement are
<br />about the same for both soils. Capability trait Vlfe-2
<br />nonirri~aletl: woodland group 1.
<br />5priu= Creek Serir~
<br />The Spring ('reek series t•nnsists of shallow, well-
<br />dr;~ined soils on upland ridges :end mountainsides. Slopes
<br />arc ; to -10 percent. These soils fm'med in locally trans-
<br />ported stony material that was derived from rhyolitic
<br />tuff and breccia.
<br />]n a represcnf^itice profile the surfact• layer is dark
<br />gracish-hro«'n stony loam 9 inches thick. Peloe' this is
<br />pale-brmti'n, calcareous gravelly and eery gravelly loam
<br />about ]0 inches thick. kh~'olitic tuff is at a depth of
<br />19 inches.
<br />Spring Creek soils receive from ll to 14 inches of
<br />31
<br />precipitation. The average annual soil temperature is
<br />42° F. The average soil temperature in summer is
<br />about 62°. The native vegetation is commonly fringed
<br />sage, winterfat, phlox, western wheatgrass, squirrel-
<br />tail, dryland sedge, and slimstem muhly.
<br />Permeability is moderately rapid. Roots can pene-
<br />trate to a depth of only about 20 inches, and available
<br />water capacity is low.
<br />Mast of the acreage is in native vegetation and is
<br />used as range and wildlife habitat.
<br />The Spring Creek soils in this survey area are mapped
<br />only with Duff son soils.
<br />Representative profile of Spring Creek stony loam in
<br />native vegetation; NWli4 sec. 3, T. 49 N., R. 1 W.,
<br />Gunnison County:
<br />A1-0 to 9 inches, dark grayish-brown (lOYR 4/2) stony
<br />loam, very dark grayish brown (IOYR 3/2) moist;
<br />weak, fine, subangular blocky structure; soft, fri-
<br />able; 10 percent angular stones and gravel; pH 6.R;
<br />clear, smooth boundary.
<br />Clce-9 to 15 inches, pale-brown (lOYR 6/31 gravelly loam,
<br />dark brown (]OYR 4/3) moist; weak, fine, sub-
<br />angular blocky structure; slightly hard, friable;
<br />40 Percent angular gravel; calcareous; thin white
<br />(lOYR 8/2) lime mats on the base of gravel; pH
<br />8.0; clear, smooth boundary.
<br />C2ca-15 to 19 inches, pale-brown (lOYR 6/3) very gravelly
<br />loam, brown (70YR 5!31 moist; massive; soft, very
<br />friable; 80 percent gravel, cobblestones, and stones;
<br />calcareous; pH R.2; clear, smooth boundary.
<br />R-19 inclics, rhyolitic tuff.
<br />The A horizon ie typically stony loam, but in places is
<br />loam end channery loam. It is 9 to ]0 inches thick. The con-
<br />tent of coarse fragments ranges from 35 in 60 percent. Depth
<br />to bedrock is i0 to 20 inches.
<br />Stony Rock Laud
<br />Stony rock land iSi~ consists mostly of exposed bed-
<br />rock, loose stones, boulders, and soils that are very
<br />shallow Deer bedrock. Exposed bedrock and stones cover
<br />25 to 90 percent of the surface area. Common ruck types
<br />are rhyolite, LuB, quartz ladle, sandstone, granite,
<br />breccia, gneiss, and schist anti small outcrops of silty
<br />shale. Slopes range from 10 to 80 percent.]ncluded in
<br />mapping are small areas of soils that are up to 40
<br />inches deep.
<br />Generally the largest area, of exposed bedrock are
<br />on southerly exposures. The very shallow soil between
<br />rocks has a Very high content of loose stones. Less
<br />bedrock is exposed on nm•therly exposures, and areas
<br />of very shallow soils are larger. Northerly exposures
<br />Commonly support more dense 'vegetation than south-
<br />erly exposures.
<br />Stom• rock land is soalre'h~t intermittent throughout
<br />the surrey area. It is rommonh on steeper terrain. The
<br />vegetation caries widely, depending on rapt=tore, eleva-
<br />tion, and exposure. Sparso stands of climatically
<br />adapted grasses, shrubs, and fortis are dominant at
<br />lower elevations. Open stands of conifers and aspen
<br />arc common where moisture is in excess of 13 inches
<br />or elevations are mm'e than 8,000 feet.
<br />Stour' rock land provides concealment and escape
<br />fm' wildlife. Deer and elk often graze the sunny slopes
<br />in winter. Capability unit \'flls-3.
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