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1. Metamorphic rocks

2. METAMORPHIC ROCKS Rocks that form from other pre-existing rock (sedimentary, igneous, or metamorphic) that have been changed from high temperature and/or high pressure

3. Conditions that cause rock to undergo metamorphism include: Heat - Under conditions of high temperature from magma contacting pre-existing rock. Pressure - Deep burial and pressure from mountain formation.

4. Types of Metamorphism

5. Contact Metamorphism Deep burial and pressure from mountain formation. The main metamorphic agent is heat . Also forms when pre-existing rock comes into contact with molten lava or magma. The heat from the molten material is hot enough to cause the minerals in the original rock to re-crystallize, but not melt.

6. Regional Metamorphism Covers large areas typically associated with mountains Deep burial and pressure from mountain formation. Heat and Pressure change the rock

7. Types of Metamorphic Rocks Foliated : rocks with mineral crystals arranged in cable-like distorted layers/structures Mineral Alignment Banding Foliation Nonfoliated : rocks with recrystallized minerals; no layering Recrystallization: This is the growth of new mineral crystals from other rocks.

8. Texture Composition Type of Metamorphism Comment Rock Name Mica Regional (Heat and Pressure increase w/ depth) Low-Grade metamorphism of SHALE Mica, Quartz, Feldspar, Amphiboles, Garnet Foliation surfaces shiny from microscopic mica crystals Mica, Quartz, Feldspar, Amphiboles, Garnet, Pyroxene Platy mica crystals visible Mica, Quartz, Feldspar, Amphiboles, Garnet, Pyroxene Compact, may split easily FOLIATED MINERAL ALIGNMENT BAND- ING Scheme for Metamorphic Rock Identification Slate Phyllite Gneiss Schist

9. Progression of Metamorphism Start with a shale and then hit it with heat and pressure! Rock Name Rock Type Grade of Metamorphism Shale Sedimentary ----- Slate Metamorphic Low Phyllite Metamorphic Low/Intermediate Schist Metamorphic Intermediate/High Gneiss Metamorphic High Molten Rock Cools into Igneous Rock ----- More Heat & Pressure

10. Shale (Sedimentary Rock) Slate (Metamorphic Rock) Heat & Pressure

11. Slate (Metamorphic Rock) Heat & Pressure Phyllite (Metamorphic Rock)

12. Phyllite (Metamorphic Rock) Schist (Metamorphic Rock) Heat & Pressure

13. With even more heat & pressure (High-Grade Metamorphism) … you end up with something that is really Gneiss!

14. Scheme for Metamorphic Rock Identification Texture Composition Type of Metamorphism Comment Rock Name Variable Contact (Heat) Various rocks changed by nearby magma/lava Quartz Metamorphism of Quartz Calcite and/or Dolomite Metamorphism of Various minerals in particles and matrix Pebbles may be distorted or stretched NONFOLIATED Regional (Heat & Pressure) Sandstone Limestone or Dolostone Hornfels Quartzite Marble Metaconglomerate

15. ESRT p. 7 Animation: Metamorphic Rock Scheme

16. Where are metamorphic rocks found? At the interface between igneous and sedimentary rocks Mountainous regions

17. THE ROCK CYCLE How are rocks classified?

18. Major Rock Groups Sedimentary Formed at the Earth’s surface Clastic (Mineral Fragments or grains, clays) Crystalline (chemical precipitates and evaporites ) Bioclastic (formed organically from shells or plants) Igneous Formed from magma (molten rock) Plutonic (intrusive):slow cooling, coarse/very coarse crystals Volcanic (extrusion): quick cooling at the surface, glassy/fine crystals Metamorphic Changed by heat and pressure

19. Fig. 2.9 MAGMA

20. MAGMA Solidification IGNEOUS

21. MAGMA IGNEOUS Plutonic Solidification

22. MAGMA Volcanic IGNEOUS Plutonic Solidification

23. MAGMA Volcanic IGNEOUS Plutonic Uplift Solidification Weathering & Erosion

24. MAGMA Volcanic IGNEOUS Plutonic SEDIMENT Solidification Weathering & Erosion SEDIMENT

25. MAGMA Volcanic IGNEOUS Plutonic SEDIMENT SEDIMENTARY Solidification Weathering & Erosion Erosion Transport Deposition

26. MAGMA Volcanic IGNEOUS Plutonic SEDIMENT SEDIMENTARY Solidification Weathering & Erosion Deposition Burial/Compaction Cementation

27. MAGMA Volcanic IGNEOUS Plutonic SEDIMENT SEDIMENTARY METAMORPHIC Increased P&T Solidification Weathering & Erosion Deposition Burial/Compaction Cementation

28. MAGMA Volcanic IGNEOUS Plutonic SEDIMENT SEDIMENTARY METAMORPHIC Increased P&T Melting Solidification Weathering & Erosion Deposition Burial/Compaction Cementation Can you see any shortcuts?

29. MAGMA Volcanic IGNEOUS Plutonic SEDIMENT SEDIMENTARY METAMORPHIC Increased P&T Melting Solidification Weathering & Erosion Deposition Burial/Compaction Cementation

30. MAGMA Volcanic IGNEOUS Plutonic SEDIMENT SEDIMENTARY METAMORPHIC Increased P&T Melting Solidification Weathering & Erosion Deposition Burial/Compaction Cementation

31. Citations of sources Slide 6 (Progression of Metamorphism of Shale) http://physics.uwstout.edu/geo/_derived/sect4.htm_txt_sect4.2.gif Slide 10 Shale: http://library.thinkquest.org/06aug/02459/rocks/sedimentary/Shale.jpg Slate: http://www.global-b2b-network.com/direct/dbimage/10260661/Grey_Slate.jpg

32. Phyllite: http://www.bedford.k12.ny.us/flhs/science/geoscience/images/phyllite.jpg