1. We have been talking about minerals primarily in the earth’s crust
What About the rest??

4. Mantle composition (rheology)
Lherzolite (60%olv 40%OPX, grt)
Harzburgite (80%olv 20%OPX)
Pyrolite (lherzolite-like)
Olivine  b-spinel
Pyroxene 
b-spinel + stishovite
Spinel 
perovskite + periclase
lithosphere
asthenosphere
Upper
mantle
410
660
MOHO
dicontinuities
Lower mantle

5. Lherzolite (60%olv 40%OPX, grt) Harzburgite (80%olv 20%OPX)
Upper Mantle Minerals
Olivine (60%), Pyroxene (30%), Garnet (10%)
Rest is compositionally homogeneous
What’s different??
Lherzolite (60%olv 40%OPX, grt)
Harzburgite (80%olv 20%OPX)
Pyrolite (lherzolite-like)
Olivine  b-spinel
Pyroxene 
b-spinel + stishovite
Spinel 
perovskite + periclase
lithosphere
asthenosphere
Upper
mantle
410
660
MOHO
discontinuities
Lower mantle

6. Upper Mantle Olivine
Olivine – Thought to be about 10-12% Fe in upper mantle
At pressures around the 410-km discontinuity, Fo-rich olivine transforms to a ccp structure called wadsleyite.
Iron rich olivines do not undergo this transformation. At higher pressures, both the Fa-rich olivine and wadsleyite transform to a spinel structure, (Mg,Fe)2SiO4, called ringwoodite.
This occurs when the pressure forces the structure to become as closest-packed as it can get  in order to become more dense it must transform to a new phase.

7. Garnet, Pyroxene
As pressure increases  Pyroxene  Garnet (primarily pyrope)
Increases from 50 to 520 km
Past 520 km, Garnet Ca-perovskite
Past 720 km, more Mg rich Garnets begin to form Mg-perovskite

8. Lower Mantle Minerals
Perovskite ((Mg, Fe)SiO3, Magnesio-wüstite: ((Mg,Fe)O), and Stishovite (SiO2)
~80% Perovskite, ~20% Magnesio-wustite, minor stishovite (which doesn’t form if Mg or Fe are around)
At these high pressures, all Si is 6-coordinate (SiO6 subunits; Octahedral coordination)

9. Perovskite
(Mg, Fe)SiO3
As the major mineral in the lower mantle, possibly the most abundant earth material!

10. Core

11. Core Outer Core Inner Core
Liquid – made of Iron (Fe) and Nickel (Ni) (about 4%) and some S, Si, and O (enough to make the density less than Fe and Ni alone)
Movement of this liquid is responsible for earth’s magnetic field
Inner Core
Solid, Hexagonally-closest packed Fe and Ni

12. Do we have any Lower Mantle Minerals??NO
How do we know they are there?
METEORITES!?!?!?!
P-S waves tell us something about composition
Nuclear chemistry also tells us something about composition
EXPERIMENTS – simulate P-T  see what you get…