1. Trace elements

2. Substitutions and partition coefficients
Normalization and spidergrams

3. Selective affinities Fe2+ Mg2+ Ni2+ Au3+ Ag3+ Compatible
(right size & charge)
Fe2+
Mg2+
Incompatible
(size/charge does
not match)

4. Rb follows K & conc. in Ksp, mica, & late melt
Ni follows Mg & conc in olivine

5. Partition coefficient Kd = Cs/Cl
Compatible, incompatible (relative to a mineral)
Bulk repartition coefficient D = S Kdi Xi

6. Which are incompatible? Why?
Compatibility depends on minerals and melts involved.
Which are incompatible? Why?
Not exact, since D varies with the composition of mins & melt

7. How will the residual liquid evolve?
Calculate DYb for…
A lherzolite (80% Ol, 10% Opx, 10%Cpx)
A Grt-bearing Lherzolite (70% Ol, 10% Opx-Cpx-Gt)
Calculate DSr for…
A Cpx-Plag cumulate (50/50)
A Cpx-Opx cumulate (50/50)
How will the residual liquid evolve?

8. Fingerprinting specific minerals:
Ni strongly fractionated  olivine > pyroxene
Cr and Sc  pyroxenes » olivine
Ni/Cr or Ni/Sc can distinguish the effects of olivine and augite in a partial melt or a suite of rocks produced by fractional crystallization
In all of the above cases using ratios, the idea is to find a mineral with a unique pair of elements for which it alone has a relatively high value of D for one element and a relatively low value of D for the other. The ratio of these elements is then sensitive only to liquid/crystal fractionation associated with that particular mineral

9. Concentration of REE in a sample

11. Chondrites

12. Contrasted REE patterns
Granites
Basalts

13. Multi-elements diagrams
Normalized to the PRImitive Mantle (close to chondrites) (Wood version)

14. Various normalizations:
To MORB (Mid-Oceanic Ridge Basalts – the most common type of basalt!)
Meaningful for basalts and co.

15. Various normalizations:
To the average continental crust.
Meaningful for granites, sediments, etc.

16. A famous “anomaly”: Eu Granites from the Cape Granite Suite
Darling-Vredenburg area

17. Kd’s for plagioclase REEs are normally 3+ (La3+, etc.)
Eu can be Eu3+ or Eu2+
Eu2+ strongly compatible
Reducing (Eu2+)
Oxydizing (Eu3+)