2022-05-10_GENERAL DOCUMENTS - M1993041

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Dowe Flats Quarry Soils and Geology Report GAYNOR SERIES The Gaynor series consists of moderately deep, well drained soils that formed in material weathered from sedimentary rocks. Gaynor soils are on hill sides and ridge crests and have slopes of 0 to 60 percent. The mean annual precipitation is about 18 inches and the mean annual temperature is about 48 degrees F. TAXONOMIC CLASS: Fine, smectitic, calcareous, mesic Ustic Torriorthents TYPICAL PEDON: Gaynor silty clay loam - grassland. (Colors are for dry soil unless otherwise noted.) A--O to 6 inches; light olive brown (2.5Y 5/3) heavy silty clay loam, olive brown (2.5Y 4/3) moist; strong fine granular structure; soft, very friable; calcareous; moderately alkaline (pH 8.0); clear smooth boundary. (4 to 8 inches thick) AC--6 to 10 inches; light olive brown (2.5Y 5/3) heavy silty clay loam, olive brown (2.5Y 4/3) moist; weak medium subangular blocky structure; extremely hard, firm; calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (3 to 5 inches thick) Ck--10 to 30 inches; light yellowish brown (2.5Y 6/3) heavy silty clay loam, light olive brown (2.5Y 5/3) moist; massive; very hard, firm, plastic; some discontinuous accumulation of secondary calcium carbonate and calcium sulfate as concretions and crystals; calcareous; moderately alkaline (pH 8.2); gradual wavy boundary. (7 to 33 inches thick) Cr--30 to 60 inches; soft calcareous silty shale. TYPE LOCATION: Boulder County, Colorado; approximately 1,850 feet south and 1,050 feet east of the NW corner of Sec. 23, T. 2 N., R. 69 W. RANGE IN CHARACTERISTICS: These soils are usually calcareous at the surface but are leached for a few inches in some pedons. Depth to the underlying paralithic contact is 20 to 40 inches. Organic carbon in the surface horizon is .8 to 1.5 percent and decreases uniformly with increasing depth. Conductivity ranges from less than 1 to about 3 millimhos and exchangeable sodium percentage usually ranges from less than 1 percent throughout the control section. Cation exchange capacity ranges from approximately 60 to 80 milliequivalents per 100 grams of clay. The control section is usually heavy silty clay loam or light silty clay but clay ranges from 35 to 50 percent, silt from 30 to 55 percent, and sand from 5 to 30 percent, with less than 15 percent fine or coarser sand. Coarse fragments range from 0 to 10 percent but are usually less than 2 percent and confined mostly to shale chips. Mean annual soil temperature is 47 to 58 degrees F. Mean summer soil temperature is 59 to 79 degrees F. The A horizon has hue of 5Y through 7.5YR, value of 5 through 7 dry, 3 through 6 moist, and chroma of 2 through 4. Its primary structure usually is granular or crumb but is weak subangular blocky in some pedons. It is soft or slightly hard and moderately alkaline or mildly alkaline. 15 May 2, 2022