Metamorphic rocks

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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 Metamorphic Rocks Metamorphic Rocks Formation 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 Types of Metamorphism Contact Metamorphism Regional Metamorphism 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 Regional Metamorphism    Covers large areas typically associated with mountains Deep burial and pressure from mountain formation Heat and Pressure change the rock Types of Metamorphic Rocks  Foliated: rocks with mineral crystals arranged in cable-like distorted layers/structures Mineral Alignment  Banding  Animation: Foliation   Nonfoliated: rocks with recrystallized minerals; no layering  Recrystallization: This is the growth of new mineral crystals from other rocks Scheme for Metamorphic Rock Identification MINERAL ALIGNMENT BANDING FOLIATED Texture Composition Type of Metamorphism Comment Rock Name Regional Mica Low-Grade metamorphism of SHALE Slate Mica, Quartz, Feldspar, Amphiboles, Garnet Foliation surfaces shiny from microscopic mica crystals Phyllite Mica, Quartz, Feldspar, Amphiboles, Garnet, Pyroxene Mica, Quartz, Feldspar, Amphiboles, Garnet, Pyroxene (Heat and Pressure increase w/ depth) Platy mica crystals visible Compact, may split easily Schist Gneiss Progression of Metamorphism Start with a shale and then hit it with heat and pressure! More Heat & 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 - 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 Rock Cycle Conclusion Fig 2.9 MAGMA IGNEOUS Solidification MAGMA IGNEOUS Plutonic Solidification MAGMA Volcanic IGNEOUS Plutonic Solidification MAGMA Weathering & Erosion Uplift Volcanic IGNEOUS Plutonic Solidification MAGMA SEDIMENT Weathering & Erosion Volcanic IGNEOUS Plutonic Solidification MAGMA SEDIMENT Weathering & Erosion Erosion Transport Deposition Volcanic SEDIMENTARY IGNEOUS Plutonic Solidification MAGMA SEDIMENT Weathering & Erosion Deposition Burial/Compaction Cementation Volcanic SEDIMENTARY IGNEOUS Plutonic Solidification MAGMA SEDIMENT Weathering & Erosion Deposition Burial/Compaction Cementation Volcanic SEDIMENTARY IGNEOUS Plutonic Increased P&T METAMORPHIC Solidification MAGMA SEDIMENT Weathering & Erosion Deposition Burial/Compaction Volcanic Can you see IGNEOUS any shortcuts? Cementation SEDIMENTARY Plutonic Increased P&T METAMORPHIC Solidification Melting MAGMA SEDIMENT Weathering & Erosion Deposition Burial/Compaction Cementation Volcanic SEDIMENTARY IGNEOUS Plutonic Increased P&T METAMORPHIC Solidification Melting MAGMA SEDIMENT Weathering & Erosion Deposition Burial/Compaction Cementation Volcanic SEDIMENTARY IGNEOUS Plutonic Increased P&T METAMORPHIC Solidification Melting MAGMA Citations   Slide (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      Slide 11:  Phyllite: http://www.bedford.k12.ny.us/flhs/science/geoscience/images/phyllite.jpg Slide 12:  Schist (1) http://www.randall.k12.wi.us/rocks/images/schist-with-garnet.jpg  Schist (2) http://www.es.ucl.ac.uk/schools/Glossary/schist.jpg Slide 13:  Gneiss (1) http://hyperphysics.phy-astr.gsu.edu/hbase/geophys/geopic/gneiss2.jpg  Gneiss (2) http://www.cropsoil.uga.edu/soilsandhydrology/images/Gneiss.jpg  Gneiss (3) http://upload.wikimedia.org/wikipedia/commons/6/60/Gneiss.jpg Slide 16:  8/16/2006 Physical Setting Regents Earth Science Exam p 18 Slide 17:  Earth Science Reference Tables p [...]... Various rocks changed by nearby magma/lava Hornfels Metamorphism of Quartz Sandstone Metamorphism of Limestone or Dolostone Pebbles may be distorted or stretched Quartzite Marble Metaconglomerate  ESRT p 7  Animation: Metamorphic Rock Scheme Where are metamorphic rocks found?  At the interface between igneous and sedimentary rocks • Mountainous regions THE ROCK CYCLE How are rocks classified? How are rocks. ..Shale (Sedimentary Rock) Heat & Pressure Slate (Metamorphic Rock) Slate (Metamorphic Rock) Heat & Pressure Phyllite (Metamorphic Rock) Phyllite (Metamorphic Rock) Heat & Pressure Schist (Metamorphic Rock) With even more heat & pressure (High-Grade Metamorphism) … you end up with something that is really Gneiss! Scheme for Metamorphic Rock Identification Texture Composition NONFOLIATED... IGNEOUS Plutonic Increased P&T METAMORPHIC Solidification MAGMA SEDIMENT Weathering & Erosion Deposition Burial/Compaction Volcanic Can you see IGNEOUS any shortcuts? Cementation SEDIMENTARY Plutonic Increased P&T METAMORPHIC Solidification Melting MAGMA SEDIMENT Weathering & Erosion Deposition Burial/Compaction Cementation Volcanic SEDIMENTARY IGNEOUS Plutonic Increased P&T METAMORPHIC Solidification... Deposition Burial/Compaction Cementation Volcanic SEDIMENTARY IGNEOUS Plutonic Increased P&T METAMORPHIC Solidification Melting MAGMA Citations   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... 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 Rock Cycle Conclusion Fig 2.9 MAGMA IGNEOUS Solidification MAGMA IGNEOUS Plutonic Solidification MAGMA Volcanic IGNEOUS Plutonic Solidification MAGMA Weathering... http://www.global-b2b-network.com/direct/dbimage/10260661/Grey_Slate.jpg      Slide 11:  Phyllite: http://www.bedford.k12.ny.us/flhs/science/geoscience/images/phyllite.jpg Slide 12:  Schist (1) http://www.randall.k12.wi.us /rocks/ images/schist-with-garnet.jpg  Schist (2) http://www.es.ucl.ac.uk/schools/Glossary/schist.jpg Slide 13:  Gneiss (1) http://hyperphysics.phy-astr.gsu.edu/hbase/geophys/geopic/gneiss2.jpg  Gneiss
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