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<br />9 <br /> <br />from such strata below the Book Cliffs (between Grand Junction, <br /> <br />~) Colorado and Price, Utah) may eventually reach the waters of the <br />....:I <br />~ Colorado River. These areas are not only typified by an underlying <br />.... <br /> <br />material containing many diagenetic soluble minerals derived from <br /> <br />the original contact with seawater, but they are also semiarid to <br /> <br />arid in nature. Such climatic regions are by definition those of <br /> <br />low annual precipitation and high evaporation (Fig. L 5), The natural <br /> <br />runoff of these regions becomes more concentrated with dissolved <br /> <br />matter, or "salt-loaded", as evaporation occurs, The marine origin <br /> <br />of these sediment~ their sha1y nature and salt loading are primary <br /> <br />causes for the saline nature of the associated surficial materials, <br /> <br />which are rich or enriched in calcium and magnesium carbonates and <br /> <br />in soluble sulfates, The Bureau of Reclamation (1974) stated that: <br /> <br />The major part of the dissolved constituents in the Colorado <br />River water is made up of the cations: calcium, magnesium <br />and sodium, and the anions: sulfate, chloride and bicarbonate. <br />These, plus minor amounts of other dissolved constituents, are <br />conunonly referred to as salinity, "salt", dissolved solids, <br />or dissolved mineral content. <br /> <br />A review of the occurrence of saline deposits within the Upper <br /> <br />Colorado River Basin revealed that almost all of these outcrop in the <br /> <br />arid-semiarid lowlands. ,Practically all the saline deposits are fine- <br /> <br />grained and most are shales. The shales of the Colorado Plateaus <br /> <br />were mostly deposited in shallow (epicontinental) seas that were <br /> <br />often very saline; much calcium sulfate, if not sodium chloride and <br /> <br />, <br /> <br />even potassium salts were, therefore, deposited contemporaneously <br /> <br />with the sediments and subsequently remobilized and diagenetica1ly <br /> <br />altered. Among the variety of saline shales in the basin (Paradox, <br /> <br />Moenkopi, Carmel, Summerville, parts of the Morrison, the <br /> <br />, <br /> <br />,1>.,';',,,,,, <br />