IX metamorphic rocks

Prograde metamorphism of shale D.. Crystallie Texture Minerals tightly interlocking due to recrystallization under pressure Evidence of Metamorphism... Additio or removal of fluids

IX Metamorphic Rocks

A. Evidence of metamorphism

B. The recipe for metamorphism

C. Prograde metamorphism of shale

D. Classification of Metamorphic Rocks

E. Metamorphism and Plate Tectonics

The

Rock Cycle

 Rock

Metamorphism

(Icreased T

& P)

 morphic rock

Partial Meltig

 Magma

 Geological Materials

Transformation Processes

 While still solid

 Into minerals that are

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

 1 Bet

(deformed)

layers

Fig 8-1, p 168

 3 Crystallie

Texture

Minerals tightly interlocking

due to recrystallization under

pressure

Evidence of Metamorphism

 Except water and

some dissolved ions

Shale

Schist

B Ingredients of Metamorphism

(high geothermal gradiets)

 Minerals stable at lower temperatures converted to

 minerals stable at higher temperatures

 Solid state chemical reactions are accelerated

0 500 1000

Temp (ºC)

A B C

Ingredients of Metamorphism

(ad stresses)

 Increased Lithostatic Pressure as rocks are buried

 Differential Pressure at convergent plate boundary or

Fig 8-3, p 169

Results of Stress (Pressure)

Ingredients of Metamorphism

 4 Additio or removal of

fluids (ad elemets)

 Water (and other fluids) within rocks and minerals

 Moving during metamorphism

 Accelerates solid-state chemical reactions and

 May change rock composition

 5 Time  Millios of years!

Prograde Metamorphism of Shale

realigmet of platy mierals

Prograde Metamorphism of Shale

 Slaty cleavage becomes

rippled ad rock has

a shee

Prograde Metamorphism of Shale

Garet, amphibole ad biotite

 Schistosity due to aligmet of

platy ad eedle likemierals

Prograde Metamorphism of Shale

grade metamorphic coditios

appear: feldspar

 Geissic badig bads of

dark ad light mierals

Fig 7.12

Prograde Metamorphism of Shale

Metamorphic Rocks of other Parent Rocks

 Marble

Crystallie calcite

Metamorphic Rocks of other Parent Rocks

 Quartz Sadstoe  Quartzite

 Graular quartz 

Crystallie quartz

Metamorphic Rocks of other

Parent Rocks

 Basalt  Amphibole Schist

 Graite  Geiss

 Uiform texture  Foliatio (schistosity ad

geissic badig)

Where does Prograde

Prograde Metamorphism in Mountain Belts

Metamorphic Grade

High

Low

Northeastern North America

Northwestern Africa

Review for Exam

For each rock type

 Various types of metamorphic foliation

 Various sedimentary structures

Reading the Grand Canyon

2 Grand Canyon Pink Granite

The Grand Canyon

Intrusive Igneous

Sedimentary RocksMetamorphic

1 Vishnu Schist (and gneiss)

3 Bright Angel Shale

4 Redwall Limestone

5 Coconino Sandstone

The Grand Staircase

Fig 8.16

The Grand Staircase

Fig 8.16

Eastern Zion National Park

Checkerboard Butte

Zion National Park

Vishnu Schist and Pink Granite