The Mancos Shale

of Western Colorado

This photograph shows a part of the Book Cliffs north of the Grand Valley. These cliffs consist of resistant Cretaceous sandstone and coal-bearing rocks that rise 1,500 to 2,000 feet above the broad Grand Valley of Western Colorado. These cliffs extend from Palisade westward 180 miles into Utah. The lower parts of this escarpment consists of Mancos shale and the white deposits seen are salt accumulations from these Mancos deposits. Crystals of gypsum can be found several inches beneath the surface of these soil deposits.

This photograph was taken on February 8, 1996. There was no snow on the ground (Grand Junction had received a sparse 0 .71 inches of precipitation since the first of January) and the high for the day was 60 degrees Fahrenheit. Note the accumulation of salts on the soil surface. The lack of rainfall allowed these salts to move from lower moist soils upward and were left behind as the moisture evaporated from the soil surface. Proper soil preparation and irrigation (to include watering during the winter) will typically correct this problem.

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