1. Summary from Previous Class 1.Earth’s Internal Layering - Crust, Mantle and Core 2.Seismology, LVZ, Lithosphere, and Asthenosphere 3.P,T, density variation in the earth’s interior 4.Transition Zone, Two-layered vs. whole mantle convection 5. Plate tectonics, Plumes, Wilson Cycle, and recent hypotheses by Anderson and Larson

2. Layer Names Inner CoreSolid Iron Outer CoreMolten Iron MantleDense silicates CrustGreat variety of minerals in the continental crust but limited in the oceanic crust

3. Meteorite Types Irons (Core Equivalent) Stony Irons (Core/Mantle Boundary) Stony meteorites Achondrites (silicate dominated) Chondrites (silicate) Carbonaceous Chondrites (only type with C & H 2 O…source of LIFE!)

4. Meteorite composition and abundance Stony meteorites (92.8%) Chondrites (85.7%) Carbonaceous (5.7%)hydrated mins. (serpentine), organic compounds, 1-9%H2O ordinary (67.6%)pyroxenes, olivines, Fe-Ni metal other (12.5%)similar Achondrites (7.1%) Ca-rich(4.7%)pyroxenes,olivines,plagioclase Ca-poor (2.4%)no plag Stony irons (1.5%) mesosideritespyrox, plag, Fe-Ni pallasitesolivine, Fe-Ni otherspyrox, oliv, Fe-Ni Irons (5.7%) octahedriteskamacite, taenite hexahedriteskamacites ataxitestaenite, kamacite Source: Emiliani (1990) Planet Earth

5. Source of Meteorites Achondrites - from Mars & Moon Chondrites - stuff terrestrial planets are made of Irons - Core of the earth Stony Irons - CMB The oldest meteorites are 4.5 billion years old

6. Achondrite

7. Iron Meteorite

8. Martian Meteorite

9. Chondrule

10. Olivine chondrule

11. Pyroxene chondrule

12. Composition of C chondrites The average Carbonaceous Chondrite Weight% Carbon 2.0 Metals 1.8 Nitrogen 0.2 Silicates 83.0 Water 1- 9.0

13. Pb-isotope isochron for the age of the earth

18. Earth as a Bar Magnet

20. Polarity Time Scale

21. Core Phase Diagram?

22. Core dT/dz Depth (km)

23. Some Statistics….. OF ALL THE METEORITES THAT FALL ON EARTH: –86% are Chondrites –7.1% are Achondrites –5.7% are Irons –And 1.5% are Stony Irons