lecture 8: metamorphic rocks - soest · lecture 8: metamorphic rocks! 1. read: chapter 9 2....
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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 **"
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
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
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
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
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
Regional metamorphism often results from directed stress
Directed Stress: Pressure is greatest in one direction
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
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 "