2. Metamorphic Rocks Foliations, and Lineations

3. Topics Fabrics Foliation, cleavage, lineation –Cleavage and Folds –Geometry –Strain significance Origin of Cleavage –Pressure solution –Passive rotation –Recrystallization Shear zones

4. Geothermal Gradient and Metamorphism

5. Naming of Metamorphic Rocks

6. Slatey cleavage

7. Gneiss

8. Looks Like Bedding, but is it?

9. Metamorphic layering Broosk Range, AK

10. Isoclinal Fold

11. Quartz-mica schist

12. Fabric Elements Bedding Compositional layering Mineral grains Fold Hinges Axial planes Planes of parting or fracture etc

13. Metamorphic Fabrics Foliation –Cleavage –Schistosity Lineation S-tectonite L-tectoniteL/S-tectonite

14. Random fabric Foliation Lineation

15. Penetrative Fabric Spaced Fabric

16. Cleavage A kind of foliation Deformation Fabric Rock splits along preferred planes Lachlan fold belt, Australia Photo by E.L.Miller

17. Spaced cleavage Cambrian Rocks, South Verkhoyansk foldbelt, Siberia

18. The beginning of Metamorphism: Axial Planar Cleavage

21. Relationship o cleavage to folding Axial-planar cleavage

23. Axial Planar cleavage

24. Processes of Cleavage Development Rotation of minerals Crenulation Pressure solution Recrystallization

25. SEM Image of Clays in Shale

26. Pressure solution in Clay-rich Limestone

27. Early pressure-solution cleavage in limestone

28. Small quartz vein cut by a spaced crenulation/solution cleavage Documenting the extent of material removal along these surfaces. Photo from David Gray, Monash University, Australia

29. Sequential diagram of % shortening by folding (initially by buckling), cleavage development and dissolution. Courtesy of David Gray, Monash University, Australia

31. Sandstone after compaction

32. Beginning of foliation

33. Crenulation Cleavage Small scale kinks and pressure solution surfaces

34. Crenulation Cleavage Beginning

35. More Advanced Fabric

36. Coarse Sandstone-Strong Foliation

37. Two Foliations! S2 S1

38. Spaced Pressure-Solution Cleavage

39. Shortening by folding vs. shortening by cleavage