IX metamorphic rocks

IX Metamorphic Rocks A B C D E Evidence of metamorphism The recipe for metamorphism Prograde metamorphism of shale Classification of Metamorphic Rocks Metamorphism and Plate Tectonics The Rock Cycle  Geological Materials Transformation Processes  Rock Metamorphism (Icreased & P)  T Metamorphic rock Partial Meltig  Magma Metamorphism Metamorphic Rocks Defiitio:     Re-crystallization of minerals While still solid Into minerals that are stable at different temperatures and Different pressures (Usually progressively higher temperatures and pressures) A Evidence of Metamorphism E.g., Sedimetary Rocks     Made of minerals derived from weathering of a parent rock Stable at atmospheric temperatures and pressures (low T & P) Originally horizontal, continuous and uniform layers Bet (deformed) layers Fig 8-1, p 168 Evidence of Metamorphism  Differetia l pressure “squashes” rock ad icluded features Flatteed Pebbles Evidence of Metamorphism  Crystallie Texture Minerals tightly interlocking due to recrystallization under pressure Evidence of Metamorphism  New mieral assemblages E.g., Shale: Clay mierals (some quartz)  Metamorphism Forms Schist: Mica, Feldspar ad other silicate mierals  B Recipe of Metamorphism  Paret Rock    Even though minerals will change Most elements are provided by parent rock Except water and some dissolved ions Shale Schist B Ingredients of Metamorphism Temp (ºC) 500 1000 A B C  Icreased Temperature (high geothermal gradiets)  Minerals stable at lower temperatures converted to  minerals stable at higher temperatures  Metamorphic Rocks of other Parent Rocks  Quartz Sadstoe   Graular quartz  Crystallie quartz Quartzite Metamorphic Rocks of other Parent Rocks  Basalt  Amphibole  Graite Schist  Geiss  Uiform texture  Foliatio (schistosity ad geissic badig) Where does Prograde Metamorphism occur? Temp (ºC) 600 1200 A B C    Where temperatures ad pressures are progressively icreased: Subductio zoes ad Moutai belts Regioal Metomorphism at Coverget plate boudaries Prograde Metamorphism in Mountain Belts Northeastern North America Metamorphic Grade High Northwestern Africa Low For each rock type discussed kow:  Grain size (rounding and sorting if sedimentary)  Texture (clastic or crystalline)  Other characteristics  Various types of metamorphic foliation  Various sedimentary structures  Environment of formation  History of formation Rock Classification Review for Exam Reading the Grand Canyon The Grand Canyon Fig 8.16 The Grand Staircase Coconino Sandstone Redwall Limestone Sedimentary Rocks Intrusive Igneous Metamorphic Bright Angel Shale Grand Canyon Pink Granite Vishnu Schist (and gneiss) The Grand Staircase Fig 8.16 Eastern Zion National Park Checkerboard Butte Zion National Park Vishnu Schist and Pink Granite [...]... resultig i silicic veis if itrusive igeous rock Fig 7.12 Metamorphic Rocks of other Parent Rocks  Limestoe  Marble  Bioclastic calcite Crystallie calcite  Metamorphic Rocks of other Parent Rocks  Quartz Sadstoe   Graular quartz  Crystallie quartz Quartzite Metamorphic Rocks of other Parent Rocks  Basalt  Amphibole  Graite Schist  Geiss  Uiform texture  Foliatio (schistosity... Mica ad Quartz  Medium-grade metamorphic  Mierals stable uder medium grade metamorphic T&P Causescoditios appear: Garet, amphibole ad biotite mierals to  Schistosity due to aligmet of grow platy ad eedle likemierals Prograde Metamorphism of Shale 4: High-Grade Metamorphism  Geiss  Course graied Feldspar, Quartz, Amphibole, Biotite Fig 7.12  High-grade metamorphic T&P Causes  Mierals... to grade metamorphic coditios separate ito appear: feldspar bads  Geissic badig bads of dark ad light mierals Prograde Metamorphism of Shale 5: Very HighGrade Metamorphism ad partial meltig Migmatite  Silica rich mierals melt first (quartz ad feldspar)  Formig silicic magma  Ijected ito fractures resultig i silicic veis if itrusive igeous rock Fig 7.12 Metamorphic Rocks of... Metamorphism of Shale (and the classification of metamorphic rocks) Shale: Fie graied Clay (ad quartz)  Mierals stable uder low T&P (atmospheric)  Compactio due to accumulatio of sedimet  Fissility alog lamiatios  Water boud i crystallie structure of clay Prograde Metamorphism of Shale  Me tamorphic grade 1: Low Grade  Rock: Slate Low grade metamorphic T&P (Water is expelled from crystallie... from crystallie structure of clay)  Mierals stable uder low grade metamorphic coditios Fie graied  Mieral compositio : Mica (ad Quartz)  Foliatio: Slaty Cleavage due realigmet of platy mierals to Prograde Metamorphism of Shale 2: Medium-Grade Metamorphism  Phillite  Courser graied Mica ad quartz  Medium-grade metamorphic T&P Causes  Slaty cleavage becomes mierals to grow rippled... Lithostatic Pressure as rocks are buried Differential Pressure at convergent plate boundary Fig 8-3, p 169 Results of Stress (Pressure)  Differetial Pressure  Parallel aligmet of platy mierals (e.g., micas) ad eedlelike mierals (e.g., amphiboles)  Forms Foliatio Ingredients of Metamorphism  4 Additio or removal fluids (ad elemets)      of Water (and other fluids) within rocks and minerals... Coverget plate boudaries Prograde Metamorphism in Mountain Belts Northeastern North America Metamorphic Grade High Northwestern Africa Low For each rock type discussed kow:  Grain size (rounding and sorting if sedimentary)  Texture (clastic or crystalline)  Other characteristics  Various types of metamorphic foliation  Various sedimentary structures  Environment of formation  History of... formation  History of formation Rock Classification Review for Exam Reading the Grand Canyon The Grand Canyon Fig 8.16 The Grand Staircase 5 Coconino Sandstone 4 Redwall Limestone Sedimentary Rocks Intrusive Igneous Metamorphic 3 Bright Angel Shale 2 Grand Canyon Pink Granite 1 Vishnu Schist (and gneiss) The Grand Staircase Fig 8.16 Eastern Zion National Park Checkerboard Butte Zion National Park Vishnu