THE DISTRIBUTION OF RARE EARTH AND TRACE ELEMENTS IN

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THE DISTRIBUTION OF RARE EARTH AND TRACE ELEMENTS IN Powered By Docstoc
					THE DISTRIBUTION OF RARE
    EARTH AND TRACE
ELEMENTS IN FRACTIONS OF
      MARINE SHALE

    Janet Frey
    D. E. Grandstaff
        Department of Geology
        Temple University
        Philadelphia, PA
                Why Shale?
•Shales comprise 60% or more of sedimentary
     rocks
• Shale reactions are important as sources and
     sinks for trace elements.
               Element Groups (Families)
Alkali Earth      Alkaline Earth   Transition Metals

Rare Earth        Other Metals     Metalloids

Non-Metals        Halogens         Noble Gases
Why Rare Earth Elements?

• Not much is know about mobility of REE
     elements in earth surface systems.

• REE have commonly been considered
     conservative in natural waters
     – water mass tracers.

• However, REE may interact with sediments.
• REE as analogs in nuclear waste disposal
     (Neptunium, Americium)

• Radioactive REE in short-term waste release
    REE concentrations in bulk shales are
            fairly well known.
However trace elements may be contained in a
 variety of phases:

•   Ion exchange sites on clays
•   Adsorbed on hydrous ferric oxides
•   Adsorbed to organic matter
•   Co-precipitated in carbonates
•   Bound in crystalline minerals

The phase in which they are contained
  determines their environmental mobility.
            (pH, redox, ionic strength)
      Method of sequential extraction
                          (Tessier et al., 1979)
1 gram of powdered rock

EXCHANGEABLE       1 m MgCl2

CARBONATE          1 m NaOAc

HFO                0.04m NH2OH·HCl - HOAc

ORGANIC            0.02m HNO3 – H2O2

CRYSTALLINE        HF – HClO4
Shale samples:

    Pierre Shale (K)    South Dakota
    Navesink (K)        New Jersey
    Hornerstown (K-T)   New Jersey
                                             Replicate Analyses
             Ex Car HFO                                    ORG  Uranium (duplicates)                             XTL

VA25-a  Va-25c




                                                                                                                                          1
                                                                                                                                          2
                                                                                                                                                U
VA25-b
     VA-25b                                                                                                                               3
                                                                                                                                          4
                                                                                                                                          5




VA25-c
     VA-25a




                 0       0.2           0.4       0.6        0.8           1            1.2            1.4        1.6         1.8    2

                 0       0.5           1         1.5            2         2.5          3              3.5        4           4.5   ppm
                                                                 Lead   (duplicates)




VA25-a
        Va-25c




                                                                                                                                          1




VA25-b
        VA-25b
                                                                                                                                          2
                                                                                                                                          3
                                                                                                                                          4
                                                                                                                                          5
                                                                                                                                                Pb
VA25c   VA-25a




                 0                 2                   4                   6                      8                    10           12


                 0                 2                   4                   6                      8                    10          ppm
                                                            Lanthanum          (duplicates0




VA25-a  Va-25c




                                                                                                                                          EX




                                                                                                                                                La
                                                                                                                                          car


VA25-b  VA-25b                                                                                                                            Hfo
                                                                                                                                          org
                                                                                                                                          XTL




        VA-25a


VA25-c
                 0             2             4              6              8                 10             12              14       16



                     0         2             4              6                 8              10             12              14     ppm
                                                Verendrye
                         1
                         10      2         4         6          8         10        12        14           16

                                                                                                   Total


                                                                                                   XTL
(REE/NASC)




                                                                                                   Org
             log [REE]




             0.1
               0.1
                                                                                                   Car

                                                                                                   Hfo




       0.01
          0.01

                              La Ce   Pr   Nd   Sm       Eu Gd La-Lu Dy
                                                                 Tb       Ho   Er   Tm   Yb    Lu
                                     Sharon Springs
     10




                                                                         Sum

             1
                                                                         Exch
REE / NASC




                                                                         Org
                                                                         XTL

                                                                         Hfo
    0.1
                                                                         Car




                 La Ce   Pr   Nd   Sm Eu   Gd   Tb Dy Ho   Er   Tm Yb   Lu
0.01
                                       Navesink
               10
               10


                                                                                 Total
                                                                                 XTL
               11
REE / NASC




               0.1
              0.1


                                                                                 Org

             0.01
             0.01
                                                                                 Hfo
                                                                                 Car
                                                                                 Ex
             0.001
             0.001
                     La Ce   Pr   Nd   Sm   Eu   Gd   Tb   Dy Ho   Er   Tm Yb   Lu
              Sample 25
Verendrye               GdN                  Legend
                                          Exchangeables
                   10         90          Carbonate
                 20             80        Iron Oxide
              30                 70       Organic
                                          Crystalline
            40                     60     Total
         50                          50
       60                             40
     70                                 30
   80                                     20
 90                                         10


Nd N 10 20 30 40 50 60 70 80 90Yb N
                         Shale Fractionation Variable
                                     Lanthanum (LREE)
                                        Lanthanum (57)


              Exch        Carb HFO   Organic                        Xtl
  SD-25
SD-25


              Smectite

  SD-24
SD-24
                                                                                         EX
                                                                                         Car
                                                                                         HFO
                                                                                         Org
                                                                                         XL
 VA-25a
VA-25


              Illite

  VA-24
VA-24



          0        5     10    15    20         25   30        35         40   45   50
                         1                  ppm
                                                          30
                         0                ppm
                       Gadolinium (MREE)
                                Gadolinium (64)


              EX             Car   Hfo       Org       Xtl
SD-25
  SD-25




SD-24
  SD-24
                                                                       ex
                                                                       car
                                                                       HFO
                                                                       org
                                                                       XL
 VA-25a
VA-25




  VA-24
VA-24



          0        2     4               6         8         10   12
                                      ppm
                                   ppm
                           Lanthanum

            Ex
                                        Glauconite
JHB-2
                                                              EX
        Carb HFO     Org                    Xtl               car
JHA-1                                                         Hfo
                                                              org
                                                              XTL
 JN-1


                                                            ppm
        0        5   10       15       20         25   30
                Gadolinium


JHB-2
                                       EX
                                       car
JHA-1                                  Hfo
                                       org
                                       XTL
 JN-1


        0   2   4       6    8   10   ppm
                        Ytterbium


JHB-2
                                                    EX
                                                    car
JHA-1                                               Hfo
                                                    org
                                                    XTL
 JN-1


        0   1   2   3      4        5   6   7   8
                       Sharon Springs



       La                       Gd                 Yb


            Ex
XTL
                Carb
            car
              Hfo
      Org




                                        Smectite
                   Verendrye



  La                    Gd              Yb


       car
             hfo


XTL


             org




                               Illite
             Hornerstown




      La           Gd                   Yb

       hfo




org                 XTL




                           Glauconite
                                   Yttrium


SD-25

                EX                  Car   Hfo   Org         XTL
SD-24


VA-25


VA-24

            0        10       20           30          40              50   ppm




JHB-2



JHA-1


 JN-1
        0                 5        10             15              20              25


        0                 5        10             15              20        ppm
SD-25
            0           50                  100         150        200              250          300




            0          50                  100          150        200         250              300 ppm
                EX Car               Hfo          Org                                     XTL
SD-24
                                                                                                          U
VA-25


VA-24

            0    0.5             1         1.5    2     2.5   3          3.5   4          4.5    ppm




SD-25

SD-24
                                                                                                        Th
VA25

VA24
        0                    5                    10          15               20                  25

        0                    5                    10    ppm
                                                              15               20                25     ppm
                                                       Uranium




JN-1    JHB2




                                                                                                         EX
                                                                                                         car
                                                                                                               U
JHA-1   JHA1                                                                                             Hfo
                                                                                                         org
                                                                                                         XTL




JHB-2    JN1




               0       1     2       3         4         5             6       7    8    9    10

                   0   1     2       3         4         5             6       7    8    9   10           ppm




JN-1

                                                                                                               Th
JHA-1


JHB-2
               0       0.5       1       1.5       2             2.5       3       3.5   4         4.5

                   0   0.5       1       1.5       2         2.5           3       3.5   4    4.5         ppm
 Conclusions
•Fractionation of REE/TE in shales is highly variable
     Depends on mineralogy, organic content
•In some cases <50% of REE in refractory phases
•Carbonate, HFO, Organic and Exchangeable
     fractions may provide a source of REE and TE
     that become mobile due to environmental
     changes in redox, pH and ionic strength.
•LREE may be less conservative than HREE;
     not reliable tracers.
•These reactions should be considered in waste
     disposal scenarios.
Thanks for
listening!