001 Abreu 003 Agena 004 Albert 006 Araki 091 Atiburcio 008 Buck 082 Byce 011 Clements 012 Colle

067 Peahu 068 Santiago 069 Shigemitsu 070 Soares 084 Teramura 086 Tomaszek 073 Wu 074 Yamamoto 075 Yanagi 077 Yokota 079 Zoller

013 Comilla 014 Cuadrado 015 Dang 016 Duncan 080 Fujihara 018 Ganther 021 Guerrero 022 Haupt 025 Hedden

027 Higa 028 Hipolito 090 Inserra 031 Jadu 030 Johnasen 034 Kaaihue 036 Keanini-White 037 Kipi 089 Lee

039 Lockett 040 Manion 041 McTigue 042 Meyers 043 Mitamura 044 Morikawa 047 Nassiri 048 Ota 088 Pavao

iClicker assignments – pick yours up

Lecture 8: Metamorphic Rocks!

1.  Read: Chapter 9 2.  Homework #8 due Tuesday 12pm

3.  Midterm #1 Thursday, September 24

001 Abreu 003 Agena 004 Albert 006 Araki 091 Atiburcio 008 Buck 082 Byce 011 Clements 012 Colle

081 Peahu 068 Santiago 069 Shigemitsu 070 Soares 084 Teramura 086 Tomaszek 073 Wu 074 Yamamoto 075 Yanagi 077 Yokota 079 Zoller

013 Comilla 014 Cuadrado 015 Dang 016 Duncan 080 Fujihara 018 Ganther 021 Guerrero 022 Haupt 025 Hedden

027 Higa 028 Hipolito 090 Inserra 031 Jadu 030 Johnasen 034 Kaaihue 036 Keanini-White 037 Kipi 089 Lee

039 Lockett 040 Manion 041 McTigue 042 Meyers 043 Mitamura 044 Morikawa 047 Nassiri 048 Ota 088 Pavao

iClicker assignments – pick yours up

Learning Objectives (LO)

What we’ll learn today:"

1. Describe the process of metamorphism"2. Compare/contrast regional and contact metamorphism"3. Describe the role of water in metamorphism"4. Describe the metamorphic grades and how they are

identified "

Lecture 8: Metamorphic Rocks"** Chapter 9 **"

“Metamorphosis” = a transformation (in appearance, character…)

migmatite

Fundamental Rock Types   Igneous Rocks: form when magma solidifies

  Sedimentary Rocks: form when sediment becomes cemented into solid rock

  Metamorphic rocks: form when heat, pressure, or hot water alter any preexisting rock

The Rock Cycle

Metamorphic Rocks   Metamorphism: process of rising temperature & pressure, or changing chemical conditions, that transforms rocks &

minerals

  Ways: 1. Heat 2. Pressure 3. Fluid activity

Metamorphic rocks are composed of sedimentary,

igneous, or metamorphic

minerals that have recrystallized

Marble from Carrara, Italy

Metamorphic rocks form when crustal rocks are exposed to heat and pressure

Clay (soft)

bake

Ceramic (hard)

Metamorphism: Temperature

  Heat a mineral: 1. becomes unstable at higher temperatures 2. atoms recombine to form new mineral

Metamorphism: Pressure

  Apply a higher pressure to mineral: 1. becomes unstable at higher pressures 2. atoms recombine to form new mineral

Olivine Basalt Serpentinite

Metamorphism: Fluid Activity   Interaction with fluids: 1. Fluids carry new chemicals to mineral 2. Chemicals react to form new mineral

Water

  Def.: intensity of metamorphism that formed the rock   As you go deeper in the Earth, it gets hotter, pressure increases   Rocks evolve through a sequence of metamorphic grades …

Metamorphic Grade

Metamorphism tells us a rock’s tectonic history

slate

phyllite schist

gneiss

Metamorphic Grade

They serve as geothermometers and

geobarometers

Index Minerals tell us a rock’s temperature and pressure history

  Textural changes: grain size, shape, alignment

- Deformation: tectonic forces that squeeze rock

- Foliation: parallel alignment of minerals

  Mineralogical changes: formation of new minerals

Metamorphic Changes

Deformation Foliation

Quartz sandstone Quartzite

Types of Metamorphism

 Contact

 Regional

 Hydrothermal

separate processes, but can happen @ same time

Contact Metamorphism = Thermal

  when magma comes in contact with basement rock at shallow depth and heats it up

  magma also brings reactive fluids

Contact Metamorphism

Limestone changed into marble & various types of

minerals

Contact metamorphism forms: Quartzite Hornfels Marble

Contact Metamorphism

  When major crustal movements build mountains and deform rocks

  Rocks deformed & heated at same time

Regional Metamorphism

regional metamorphism

Usually occurs across wide areas.

Regional Metamorphism

Regional metamorphism often results from directed stress

Directed Stress: Pressure is greatest in one direction

Directed stress results in

folding of rock layers

Directed stress also results in foliation of rock texture

Regional Metamorphism = stress = foliation

In addition to heat and pressure, chemically active fluids transport heat and promote recrystallization

Magma + silca-rich liquid (with iron) = amethyst crystals

Hydrothermal Metamorphism

Basalt

Serpentinite

Water

• Heat and pressure release chemically active fluids from rocks. • These fluids transport heat, ions dissolve in hot water • Reactions promote recrystallization

Metasomatism can also produce gold, silver and other valuable ores.

Vein of gold ore in metamorphic rock

Hydrothermal Metamorphism

Gold and silver from a mine near Oatman, AZ: http://www.youtube.com/watch?v=ksaS1Wzj4IY

  Slates

  Phyllite

  Schists

  Gneisses

Common Metamorphic Rocks

sandstone quartzite

Common Metamorphic Rocks

limestone marble

Common Metamorphic Rocks

shale schist

Common Metamorphic Rocks

claystone slate

Common Metamorphic Rocks

Slate roof

Metamorphic rocks are used as building materials

schist marble countertops

Geology Kitchen: Metamorphism

Plate Movement Powers the Rock Cycle

Igneous Sedimentary

Metamorphic

Action Items for Tuesday, Sept. 22

1.  Read Chapter 9 2.  Complete homework assignment #8

What you should know from today:"

1. Describe the process of metamorphism"2. Compare/contrast regional and contact metamorphism"3. Describe the role of water in metamorphism"4. Describe the metamorphic grades and how they are

identified "