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Metamorphism & Metamorphic Rocks

Metamorphism & Metamorphic Rocks. How do Metamorphic rocks form?. The rock that forms depends on:. Why Should You Study Metamorphic Rocks?. What are the 3 Agents of Metamorphism?. Heat ___________ the rate of chemical reactions. Sources of Heat:

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Metamorphism & Metamorphic Rocks

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  1. Metamorphism & Metamorphic Rocks

  2. How do Metamorphic rocks form? The rock that forms depends on:

  3. Why Should You Study Metamorphic Rocks? What are the 3 Agents of Metamorphism?

  4. Heat ___________ the rate of chemical reactions. Sources of Heat: How does TIME affect transformations?

  5. PRESSURE Lithostatic

  6. PRESSURE Differential __________:

  7. Chemically Active Fluids Sources of fluids: • . • . • .

  8. Types of Metamorphism

  9. Regional Metamorphism

  10. Contact Metamorphism Alteration occurs because:

  11. Aureole Width determined by:

  12. Index Minerals

  13. Dynamic / Cataclastic Metamorphism Mylonites

  14. How Are Metamorphic Rocks Classified? Two Groups foliation

  15. Foliated Meta. Rocks Rock Typical Meta. Features Parent Name Minerals Grade of Rock Rock Slate clays, micas, low fine-grained, shale, chlorite splits uniformly vol. ash Phyllite quartz, micas, low-med fine-gr, glossy shale chlorite “crinkled” Schist micas, chlorite, med-high distinct foliation shale, talc, garnet visible carbonates, hbl basalt/gabbro Gneiss qtz, feldspar, high light & dark shale, hbl, micas bands sandstone, basalt/gabbro felsic ign. Amphibolite hbl med-high dark, weak fol. basalt/gabbro Migmatite qtz, feldspar, very granite streaks felsic ign. & hbl, mica high in gneiss sed. mixed

  16. SLATE (very fine-grained, foliated) • formed by ____________, ___________metamorphism • used for

  17. PHYLLITE (fine-grained, foliated) • glossy sheen • coarser-gr. than slate • “crinkled” appearance

  18. SCHIST (medium-grained, foliated) • platy/elongate minerals • _________________________ metamorphismSchistose foliation

  19. GNEISS (medium-grained, foliated) • ______________ • ________________________ metamorphism • Light bands  granular minerals. (______________________) • Dark bands  platy/elongate min. (______________________)

  20. AMPHIBOLITE (med-gr, foliated)hornblende & plagioclase (___________________ regional meta.) MIGMATITES(mixed rocks) • _________________________metamorphism • High-grade meta. rx intermix w/ streaks of granite. Georgian Bay, Ontario, Canada

  21. Nonfoliated Metamorphic Rocks

  22. Nonfoliated Meta. Rocks Rock Typical Meta. Features Parent Name Minerals Grade of Rock Rock Marble calcite, low-high interlocking limestone, dolomite grains dolostone Quartzite quartz med-high interlocking quartz grains, hard sandstone Greenstone chlorite, epidote, low-high fine-grained mafic ign. hornblende green color Hornfels micas, garnet, low-med fine-grained, mudrocks quartz hard, dense Anthracite carbon high black, lustrous, coal subconchoidal fracture

  23. C Marble • ________________________________ metamorphism • Parent Rock = How is Marble used? metamorphism

  24. QUARTZITE • _____________________________________ metamorphism • Parent Rock = ________________________ • Hard & compact w/ uniform strength [breaks across grains rather than around them] • used in __________________________________________ metamorphism

  25. Greenstone (____________________ meta) • Parent rock = ________________________(green color from chlorite, epidote, & hornblende) Hornfels (__________________________ meta) • Parent rock =__________________________ • equidimensional grains Anthracite • Parent rock = ___________________________

  26. What Are Metamorphic Zones? Isograd

  27. Does Metamorphism Relate to Plate Tectonics? Low-temp/high-press _______ part of subducting plate High-temp./high-press _______ part of subducting plate High-temp/low-press _________ meta. follows

  28. Natural Resources Minerals used: talc graphite garnet kyanite asbestos {Chrysotile silky fibers 95% of all asbestos used in the U.S.} {Crocidolite long, straight fibers This variety presents a health risk. EPA policies treat all asbestos the same.} Chrysotile

  29. Ore Deposits (hydrothermal contact meta.) Ore Mineral Formula Uses Copper Bornite Cu5FeS4 transportation, communications Iron Hematite Fe2O3 steel manufacturing Magnetite Fe3O4 Lead Galena PbS batteries, pipes, solder Tin Cassiterite SnO2 plating, solder, alloys Tungsten Scheelite CaWO4 metal hardening, Wolframite (Fe,Mn)WO4 carbide manufacturing Zinc Sphalerite (Zn,Fe)S batteries, brass making, galvanizing iron

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