1. Rocks The Geologic Dictionary

2. Rocks are made of Minerals (Minerals in Granite)

3. Soil, sediment, weathered rock, regolith

4. Rock Cycle Magma Igneous Rocks Sedimentary Rocks Metamorphic Rocks Sediment Crystallization Melting Metamorphism Lithification Weathering Erosion Transport Deposition

5. Rock Identification is based on: Composition What minerals make up the rock? Texture What is the shape, size and orientation of the mineral grains that make up the rock? Major Difference: Crystalline vs. Clastic

6. Proportions of Rock Types on the Earth igneous & metamorphic rocks = crystalline rocks

7. Igneous Rocks Identification

8. Igneous Composition Mafic Felsic

9. Igneous Minerals (p.21)

10. Igneous Textures - Crystalline Coarse GrainedFine Grained

11. Igneous Textures - Crystalline Porphyritic Phenocrysts Groundmass

12. Igneous Textures - Crystalline Glassy Vesicular

13. Igneous Textures - Pyroclastic/Fragmental Made of rock fragments rather than crystals

14. Igneous Rocks GraniteDioriteGabbro RhyoliteAndesiteBasaltDacite Granodiorite Mafic IntermediateFelsic Fine Coarse

15. Ultramafic Rock - Dunite

16. Igneous Rocks (p.20)

17. Igneous Rocks Interpretation

18. Sir James Hall Scottish Geologist

19. Igneous Rock “Translations” Composition (Mafic v. Felsic) Texture Grain Size, etc. Magma source How quickly and where magma cooled

20. Magma Source: Partial Melting Mineral Hypothetical Solid Rock: Intermediate Composition A (Mafic) B (Int) C (Felsic) Melting Temp 1200°C 1000°C 800°C Temperature = 500°C

21. Magma Source : Partial Melting Mineral A (Mafic) B (Int) C (Felsic) Melting Temp 1200°C 1000°C 800°C Temperature = 1400°C Intermediate Magma (All Minerals Melt)

22. Magma Source : Partial Melting Mineral A (Mafic) B (Int) C (Felsic) Melting Temp 1200°C 1000°C 800°C Temperature = 900°C Magma

23. Mineral A (Mafic) B (Int) C (Felsic) Melting Temp 1200°C 1000°C 800°C Temperature = 900°C Magma Magma Separates Felsic Remaining Rock: More Mafic

24. Bottom Line on Partial Melting Partial Melting produces a magma that is more felsic than the parent rock Rock Ultramafic Mafic Intermediate Felsic Magma from Partial Melting Mafic Intermediate Felsic (more) Felsic

25. Composition: Magma Source MaficIntermediateFelsic Source: Partial Melting of ultramafic mantle at Divergent Zones and… Ultramafic mantle

26. Composition: Magma Source MaficIntermediateFelsic Source: Partial Melting of ultramafic mantle at Divergent Zones and … Hot Spots

27. Composition: Magma Source MaficIntermediateFelsic Source: Partial Melting of mantle, ocean crust and continent at Subduction Zones

28. Composition: Magma Source MaficIntermediateFelsic Source: Partial melting felsic continent above Hot Spots & Subduction Zones

29. Magma Rises and Cools Magma Chamber Surface Intrusive (Plutonic) Extrusive (Volcanic)

30. Grain Size: Plutons and Volcanoes Fine Grained Coarse Grained

31. Name this Igneous Feature… Igneous Dike

32. Plutonic Structures Xenoliths Source: William E. Ferguson

33. Why do we find Plutons at the Surface? Sierra Nevada Mountains Batholith, California Uplift & Erosion

34. Intermission: Quiz What Can you say about the history of this rock? Basalt Magma produced by partial melting of the mantle that erupted from a volcano at a divergent zone or hot spot.

35. Intermission: Quiz What Can you say about the history of this rock? Gabbro Magma produced by partial melting of the mantle that cooled underground (plutonic) at a divergent zone or hot spot.

36. Intermission: Quiz What Can you say about the history of this rock? Granite Magma produced by partial melting of the continental crust that cooled underground (plutonic) at a subduction zone or continental hot spot.

37. Intermission: Quiz What Can you say about the history of this rock? Andesite Magma produced by partial melting of the mantle, ocean crust & continental crust, that erupted from a volcano at a subduction zone.