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<br />Table 6. Chemical analysis of selected minor. and trace-element constituents and physical properties from duplicate samples
<br />collected in and near the Greater Aneth Oil Field, San Juan County, Utah, November 1992 to September 1994
<br />[mg/L. milligrams per liter; 1lg!L, micrograms per liter; j.LSlcm, microsiemens per cenlimefer.31 25 degrees Celsius; <. less Ihan reported value; NO, nol
<br />detcnninedl
<br />Map number: Refer ro table I and figure lO; DUP. designlltes field dupljcate sample for corresponding map number.
<br /> Specific
<br />W Fluor. Mang- Stront- Vana- Bro- conduc-
<br />C}1 Map ide Silica Barium Boron Iron anese ium dlum Lithium Iodide mlde lance
<br />-.]' number (mgIL) (mgIL) (J1g1L) (~gIL) (~gIl) (~gIl) (~gIl) (~gIl) (~gIL) (mgll) (mgIL) (~S/cm)
<br />'-.)1
<br /> Collected on November 16, 1992
<br />N41 0.6 10 <100 240 <10 ND 1,100 2.4 710 0.019 0.25 3.250
<br />DUP 2.3 10 <100 250 <10 ND 1,100 <1.0 700 .012 .09 3,210
<br /> Collected on April 1, 1993
<br />N46 2.9 8.7 <\00 2,500 30 30 4.800 34 1,200 .027 .69 8.390
<br />DUP 2.9 8.7 <\00 2.500 30 30 4,800 34 1,200 .027 .69 8,390
<br /> Collected on June 16, 1993
<br />DI 1.1 14 <100 120 <10 <10 3,200 3.2 370 .009 .52 3.600
<br />DUP 1.1 13 <100 130 <10 <10 3.300 3.5 370 .009 .52 3,630
<br /> Collected on November 4, /993
<br />N44 1.0 13 <100 110 13 38 270 10 .006 .04 660
<br />DUP .9 13 <100 110 12 33 280 9 .006 .04 660
<br /> Collected on April 21, 1994
<br />UPZ3 L5 II <100 700 510 60 5,100 8.4 530 .140 22 4,610
<br />DUP 2.7 II <100 700 250 60 5,200 8.9 530 .130 2.2 4,560
<br /> Collected on September 21, 1994
<br />NI7 .7 1\ <100 5,400 6,800 310 5.900 ND 2,000 .290 2.4 15,000
<br />DUP .7 10 <100 5,600 8.000 310 5,200 ND 2.000 .300 2.5 14,700
<br />
<br />The major anions in water from wells in the
<br />Navajo aquifer are bicarbonate, sulfate, and chloride.
<br />In most recharge waters, bicarbonate is the major anion,
<br />probably from dissolution of calcite cement and
<br />because bicarbonate is the major anion in precipitation.
<br />Concentrations of sulfate in water could be derived
<br />from oxidation of sulfide minerals, particularly pyrite
<br />(Kimball, 1992, p. 98), possible dissolution of gypsum,
<br />or from mixing with saline water in downgradient
<br />areas. High concentrations of chloride are not present
<br />in water from the Navajo aquifer in upgradient areas;
<br />consequently, high concentrations of chloride in water
<br />in down gradient areas are the result of mixing with
<br />saline water or possibly from localized dissolution of
<br />
<br />36
<br />
<br />evaporite minerals in the Navajo aquifer (refer 10 nexr
<br />section of report). Because of the wide range of dis-
<br />solved-solids concentralions in the upper Paleozoic
<br />aquifer (pI. I), dissolved-solids concentrations in water
<br />from the Navajo aquifer, particularly sulfate and chlo-
<br />ride concentrations, also could be expected to vary sub-
<br />stantially throughout the study area, if mixing between
<br />these units takes place. This observed variance in salin-
<br />ity also might be explained by localized areas of more
<br />mineralized water in the Navajo aquifer (Buck Stein-
<br />graber, Mobil Exploration and Producing, U.S.. Inc.,
<br />oral commun., 1993).
<br />
<br />The major anions and cations form the basis for
<br />three main water types that can be related to salinity.
<br />
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