Metamorphism Changes in Rock Composition or Texture

Slides:



Advertisements
Similar presentations
Metamorphic Rocks
Advertisements

“If something is gneiss, don’t take it for granite.”
Chapter 3: Rocks Table of Contents Section 3: Metamorphic RocksMetamorphic Rocks.
Formation of Metamorphic Rocks
Metamorphism Changes in Rock Composition or Texture
METAMORPHISM.
Metamorphic Rocks: Windows into the Earth’s Interior Metamorphic rocks form by the alteration of pre-existing rocks in the solid state by heat, pressure,
Metamorphism and Metamorphic Rocks
Modification of Rocks by Temperature and Pressure
H.W. #3 + Read Solar Nebula Theory Study Guide for exam 2 Study Area for lab has practice exam All missed labs must be made up before lab exam All missed.
Metamorphism The transformation of rock by temperature and pressure Metamorphic rocks are produced by transformation of: Igneous, sedimentary and igneous.
Metamorphism: New Rocks from Old
Metamorphic Rocks. What is metamorphic? These rocks were at one time either sedimentary or igneous. (The parent rocks) A change must occur to be classified.
4-4 pgs IN: What are some ways that sedimentary rock can form? Can you classify the four we looked at?
Review Concepts on Deformation and Metamorphism. Which statement regarding synclines is true? A. Limbs dip toward the axial plane where the oldest strata.
Metamorphic Rocks Chapter 3.4.
Introduction to Metamorphic Petrology
Chapter 2 Rocks: Mineral Mixtures
Metamorphism Changes in Rock Composition or Texture Due to Heat, Pressure and Action of Fluids.
Gregory G. Dimijian/Photo Researchers cd/EM - F. Metamorphic Rocks Metamorphism Metamorphism: to change form Metamorphic rock solid state. Metamorphic.
Metamorphism and Metamorphic Rocks
Metamorphic Rocks Rocks Under Stress. Metamorphism Recrystalization Solid-State Chemical Reactions No Melting.
Section 3: Metamorphic Rocks Study Guide
METAMORPHIC ROCK.
Metamorphism Changes in Rock Composition or Texture Due to Heat, Pressure and Action of Fluids.
Metamorphic Rocks. What causes metamorphism? Heat Pressure Reaction with fluids.
Lab 7 Metamorphic Rocks. Metamorphic rocks: –rocks changed by T, P, or action of watery hot fluids Protolith: –parent rock –can be ign, sed, mm.
Metamorphic Rocks A.Evidence of metamorphism B.The ingredients of metamorphism C.Classifying metamorphic rocks D.Metamorphism of shale (& other parent.
Metamorphic Rocks Change is Good.
Metamorphic Rocks. Transforming Rocks Rocks change because of changes in temperature and pressure, or the presence of hot, watery fluids. Mineral grains.
Metamorphism and Metamorphic Rocks Physical Geology.
Modification of Rocks by Temperature and Pressure
... the textural and mineralogical change rocks undergo when put under great heat and/or pressure. Metamorphism.
Chapter 8 Metamorphism and Metamorphic Rocks. Introduction  Metamorphism - The transformation of rocks without melting, usually beneath Earth's surface,
Metamorphism and Metamorphic Rocks. Metamorphism The transformation of rock by temperature and pressure Metamorphic rocks are produced by transformation.
8. METAMORPHIC ROCKS.
Table of Contents Chapter 3: Rocks Section 3: Metamorphic Rocks.
4 ~ 4 Metamorphic Rocks happen because of 1
Metamorphic Rocks Chapter 6 Dynamic Earth.
Metamorphic Rocks.
Metamorphic Rocks Metamorphic Rocks Definitions Definitions
Metamorphic Rocks Lecture
Stage 3 Revision Metamorphic Rocks.
What is a sedimentary rock?
Chapter 6 – Section 4: Metamorphic Rock
Metamorphic Rock.
Types of Rock.
Metamorphism Changes in Rock Composition or Texture
Metamorphic rocks Today’s Chapter 8: Lecture
METAMORPHIC ROCKS.
Chapter 2 lesson 3: Metamorphic Rocks
4-4 Metamorphic Rocks —due to heat (no melting), pressure and/or chemical reaction marble.
Alteration of Rocks by Temperature and Pressure
Metamorphic rocks.
Rock Cycle
The Rock Cycle.
Chapter 6.
What is the process of metamorphism?
Metamorphism and Metamorphic Rocks
Metamorphic Rock.
Earth Science Metamorphic rockS.
Chapter 4 Section 4 Metamorphic Rock
Metamorphic Rocks Formed from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary,
Metamorphic Rock.
Changing form due to heat and/or pressure
Metamorphic Rocks Chapter 3.4.
4-4 Metamorphic Rocks —due to heat (no melting), pressure and/or chemical reaction marble.
Metamorphic Rocks.
Metamorphic Rocks happen because of: 1
Presentation transcript:

Metamorphism Changes in Rock Composition or Texture Due to Heat, Pressure and Action of Fluids

We Do Not Live at “Normal” Conditions By the standards of Earth’s interior, we live in a frozen vacuum Things that look “abnormal” to us are normal behavior for materials Solids can flow Solids can react chemically with each other A given material can have several different atomic structures

Chemical Changes in Rocks Weathering At Surface Diagenesis Sedimentary Rocks Metamorphism Starts about 200 C Outside range of normal near-surface conditions

Where Does the Heat Come from? Uranium and Thorium  Other Elements + Lead + Radiation (about 90%) Potassium-40  Calcium-40 or Argon-40 + Radiation (about 10%) Possibly some primordial heat (controversial)

Where Does the Pressure Come from? Air Pressure = 14 P.s.i. (1 Atmosphere or 1 Bar = 100 kPa) Pressure Beneath 10 Meters (33 Ft.) Of Water = 1 Atm. = 1 Bar Same Pressure Beneath 3.5 m (10 ft.) Of Rock Pressure in Deepest Part of Ocean = 1000 Bars Pressure under One Mile of Rock = 500 Bars 1000 Bars (2 Mi. or 3.5 km Of Rock) = 1 Kilobar (Kb.) = 100 MPa

Pressure Units 1 Newton (N) = gravitational attraction on 100 grams One Newton = 7 Fig Newtons 1 Pascal (Pa) = 1 N/square meter 1 Pascal = pressure under thin cardboard or 0.1 mm water A Thin section exerts about 1 Pa pressure on the slide One bar = 1 atm = 100 kPa 1 MPa = 10 bars 1 GPa = 10 kilobars

Types of Metamorphism Contact Around Intrusions or Local Heat Sources Regional Usually Accompanied by Deformation Cataclasis Shearing and fault zones Shock Ultra-high pressures and rapid deformation

What Happens During Metamorphism Minerals React to Form New Minerals 2SiO2 + CaMg(CO3) 2 == CaMgSi2O6 + 2CO2 Quartz + Dolomite == Pyroxene Minerals Change Form Al2SiO5 == Al2SiO5 Andalusite == Kyanite New Materials Are Added (Metasomatism) CaMg(SiO2)2 + 2CO2 == CaMg(CO3)2 + 2SiO2 Pyroxene + CO2 == Dolomite + Quartz Minerals in Solution == Ore Bodies Recrystallization Cataclasis Shock Metamorphism

Polymorphism Al2SiO5 Andalusite Kyanite Sillimanite Ice - 6 high pressure forms Diamond - Graphite Calcite - Aragonite Quartz - - Tridymite - Cristobalite (increasing temperature) - Coesite - Stishovite (increasing pressure)

Why Don't Rocks "De-metamorphose"? Reactions Can't Reverse Because Ingredients Lost 2AlSi2O5(OH) == Al2SiO5 + 3SiO2 + H2O Clay Mineral == Andalusite + Quartz + Water (Lost) An example of carbonate metamorphism: CaMg(CO3) 2 + 2SiO2 == CaMgSi2O6 +2CO2 Dolomite + Quartz == Pyroxene + CO2 (Lost) Reactions "Freeze" Sometimes it Does Happen if Fluids Present Retrograde Metamorphism On the surface we call it weathering

Foliation Foliation is a sheetlike structure that forms when rocks are deformed.

Foliation Flattening Grain Rotation Solution New Minerals Partial Melting Shearing

Foliation In every case, the foliation is: In the direction of least resistance at right angles to the direction of greatest compression.

Metamorphic Grade - Degree to Which the Rock Has Changed Composition Can Often See Original Bedding Can Sometimes Even See Deformed Fossils At High Grades, Rocks Can Often Lose All Trace of Their Original Appearance

Major Metamorphic Rock Types Temp C Temp F Coal Limestone Sandstone Basalt Shale Index Minerals Lignite Bituminous 500 Anthracite 300 600 Graphite Marble Slate Chlorite 700 Greenstone 800 Quartzite Phyllite Biotite 900 Schist Garnet 1000 Amphibolite Staurolite 1100 Gneiss Kyanite 1200 Sillimanite Melting Begins

Major Metamorphic Rock Types Temp C Temp F Coal Limestone Sandstone Basalt Shale Index Minerals Lignite Bituminous 500 Anthracite 300 600 Graphite Marble Slate Chlorite 700 Greenstone 800 Quartzite Phyllite Biotite 900 Schist Garnet 1000 Amphibolite Staurolite 1100 Gneiss Kyanite 1200 Sillimanite Melting Begins

Major Metamorphic Rock Types Temp C Temp F Coal Limestone Sandstone Basalt Shale Index Minerals Lignite Bituminous 500 Anthracite 300 600 Graphite Marble Slate Chlorite 700 Greenstone 800 Quartzite Phyllite Biotite 900 Schist Garnet 1000 Amphibolite Staurolite 1100 Gneiss Kyanite 1200 Sillimanite Melting Begins

Major Metamorphic Rock Types Temp C Temp F Coal Limestone Sandstone Basalt Shale Index Minerals Lignite Bituminous 500 Anthracite 300 600 Graphite Marble Slate Chlorite 700 Greenstone 800 Quartzite Phyllite Biotite 900 Schist Garnet 1000 Amphibolite Staurolite 1100 Gneiss Kyanite 1200 Sillimanite Melting Begins

Major Metamorphic Rock Types Temp C Temp F Coal Limestone Sandstone Basalt Shale Index Minerals Lignite Bituminous 500 Anthracite 300 600 Graphite Marble Slate Chlorite 700 Greenstone 800 Quartzite Phyllite Biotite 900 Schist Garnet 1000 Amphibolite Staurolite 1100 Gneiss Kyanite 1200 Sillimanite Melting Begins

What About Other Rocks?

Metamorphic Facies Depth\Temp 300C 400C 500 C 600 C 700 C 800 C 5 km Zeolite Contact Metamorphism - Andalusite forms 10 km - 3 kb Greenschist Chlorite, Biotite form Slate Greenstone Quartzite Marble Amphibolite Garnet, Staurolite, Kyanite form Schist Amphibolite Gneiss Granulite Sillimanite forms Muscovite breaks down to K-feldspar Partial Melting 15 km Blueschist 20 km - 6 kb 25 km 30 km - 9 kb 35 km 40 km - 12 kb Not Found Eclogite (Mantle)

Metamorphic Map

Mantle Rocks

Metamorphism and Plate Tectonics