Transcript Chapter 9

Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Sedimentary Rock Teams:
Breccia
Sandstone
Siltsone
Shale
Limestone
Shale
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
CHAPTER 9
Metamorphic Rocks
Learning Objectives
1) I can explain what defines a metamorphic rock as well as why they are valuable.
2) I can describe the three types of metamorphism: regional and contact metamorphism and
metamorphism with chemically active fluids
3) I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
4) I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree
of metamorphic grade.
5) I can relate metamorphic rock type, facies, and grade to different tectonic processes
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
CHAPTER 9
Metamorphic Rocks
Learning Objective 1
I can explain what defines a metamorphic rock as well as why they are valuable.
Team Competition
Metamorphic rocks are derived from
rocks
Rock metamorphism is caused by
involves changes in
, and
of a rock
If a rock is heated to the point at which it melts then
Presented by Team Breccia
Critique by Team Sandstone
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
.
Learning Objective 1
I can explain what defines a metamorphic rock as well as why they are valuable.
Metamorphic Rocks are commonly exposed at
the surface:


In mountain ranges
As old rocks in continental interiors
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 1
I can explain what defines a metamorphic rock as well as why they are valuable.
Geology in OUR LIVES
Marble from Carrara, Italy
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 1
I can explain what defines a metamorphic rock as well as why they are valuable.
Geology in OUR LIVES
Slate
roof
schist
marble countertops
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 1
I can explain what defines a metamorphic rock as well as why they are valuable.
Ore deposits: are found in igneous rocks (crystal settling) and metamorphic rocks.
Many metallic ores are created by metamorphism due to rock interaction with chemically
reactive fluids
Learning Objective 2
I can describe the three types of metamorphism: regional and contact metamorphism and
metamorphism with chemically active fluids
Team Competition
Contact metamorphism is defined as
often occurs
Regional metamorphism is defined as
often occurs
Presented by Team Sandstone
Contact
metamorphism
and
.
and
.
Critique by Team Siltstone
Regional
metamorphism
Learning Objective 2
I can describe the three types of metamorphism: regional and contact metamorphism and
metamorphism with chemically active fluids
Wealth of ores in massive sulfides
produced by hydrothermal venting
Learning Objective 2
I can describe the three types of metamorphism: regional and contact metamorphism and
metamorphism with chemically active fluids
Iron
sulfide
HOT FLUID, interacts with rock & causes
metamorphism (metasomatism) Products
often found in hydrothermal vein fillings
and massive sulfides.
Learning Objective 2
I can describe the three types of metamorphism: regional and contact metamorphism and
metamorphism with chemically active fluids
Ore deposits: are found in igneous rocks (crystal settling) and metamorphic rocks.
Many metallic ores are created by metamorphism due to rock interaction with hot, chemically
reactive fluids
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Question 1: Which of these are foliated rocks?
A.
B.
C.
D.
Phyllite
Quartzite & Marble
Gneiss & Phyllite
Marble & Phyllite
Quartzite & Gneiss
Marble
Quartzite
Gneiss
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Question 2: Which of these are nonfoliated rocks?
A.
B.
C.
D.
Phyllite
Quartzite & Marble
Gneiss & Phyllite
Marble & Phyllite
Quartzite & Gneiss
Quartzite
Gneiss
Marble
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Question 3: Which of these are foliated rocks?
A.
B.
C.
D.
Quartzite & Anthracite
Gneiss & Schist
Quartzite & Schist
Antracite & Gneiss
Schist
Anthracite
Quartzite
Gneiss
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Question 4: Which of these are nonfoliated rocks?
A.
B.
C.
D.
Schist & Metaconglomerate
Slate & Hornfels
Slate & Schist
Metaconglomerate
Metaconglomerate & Hornfels
Schist
Hornfels
Slate
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Team Competition
Granite is an
rock; gneiss is a
Foliation is created when
Foliation occurs in what type of metamorphism?
Presented by Team Siltstone
rock.
.
.
Critique by Team Shale
Directed Stress
Gneiss
Granite
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Team Competition
Conglomerate is a
rock; metaconglomerate is a
Nonfoliation metamorphic rocks are created by
Nonfoliated rocks occur by what type of metamorphism?
Presented by Team Shale
Critique by Team Limestone
Metaconglomerate
Conglomerate
rock.
.
.
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Question 5
The parent rock, or protolith of metaconglomerate is...
A) Shale
B) Limestone
C) Sandstone
D) Conglomerate
E) None of the above: Metaconglomerate IS a protolith
Metaconglomerate
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Question 6
The parent rock, or protolith of Slate is...
A) Shale
Slate
B) Limestone
C) Sandstone
D) Coal
E) None of the above: Slate IS a protolith
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
FOLIATED metamorphic rocks: aligned or bands of
minerals deformed by directed stress. Some (slate) break
along cleavage planes created by mineral layers (not along
crystalline structure that creates cleavage of minerals)
Slate (aphanitic) Fractures
along parallel planes.
Gneiss Minerals
segregated into bands.
Phyllite Parallel
mineral arrangement.
Schist - parallel to subparallel arrangement.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Shale (sedimentary
rock made of clay)
Shale is the protolith of slate
Slate is the
protolith of phyllite
Phyllite is the
protolith of schist
Slate
Schist is the
protolith of gneiss
Phyllite
Phyllite
Schist
Gneiss
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Nonfoliated rocks recrystallize without directed stress so there is no mineral alignment. This often
occurs by contact metamorphism.
Team Competition
Match daughter metamorphic rocks (left) with the parent protoliths (right)
Presented by Team Limestone
Critique by Team Breccia
Quart Sandstone
Quartzite
Hornfels
Shale
Marble
Conglomerate
Anthracite
Metaconglomerate
Coal
Limestone
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Nonfoliated rocks are recrystallized but without directed stress so there
is no mineral alignment. This often occurs by contact metamorphism
Quart Sandstone
Quartzite
Shale
Hornfels
Limestone
Marble
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 3
I can explain the different types of foliated and nonfoliated metamorphic rocks, how they form, and
identify their protoliths
Increasing metamorphic grade
Marble
Metaconglomerate
Anthracite
Hornfels
Quartzite
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 4
I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree of
metamorphic grade.
Question 1: In which direction is temperature AND pressure increasing
A. Upper right to lower left
Protolith or
B. Top to bottom
C. Upper left to lower right
D. Lower left to upper right
E. Right to left
Learning Objective 4
I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree of
metamorphic grade.
Shale
Protolith or
Slate
Phyllite
Phyllite
Schist
Gneiss
Learning Objective 4
I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree of
metamorphic grade.
Slate
Phyllite
Phyllite
Schist
Gneiss
Learning Objective 4
I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree of
metamorphic grade.
Team Points
These minerals are effective geothermometers (measure temperature) and
geobarometers (measure pressure). If you had a metamorphic rock that had
garnet in it. You could infer it came from what depth and what temperature?
Learning Objective 4
I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree of
metamorphic grade.
Team Points
True or False: Feldspar and Quartz are excellent geobarometers and
geothermometers.
FALSE
Learning Objective 4
I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree of
metamorphic grade.
Team Points
A large geothermal gradient corresponds to a rapid increase in temperature with depth; a
low geothermal gradient corresponds to a slow increase in temperature with depth
1) Which line represents the greater
geothermal gradient
A
(i) active volcano
B
This contour
marks where
temperature
is 500oC
2) Order tectonic settings (i)-(iii) from
lowest to highest geothermal gradient
(ii) continental
subduction zone
(iii) mountain
belt
Learning Objective 4
I can relate the foliated metamorphic rocks, index minerals, and metamorphic facies, to the degree of
metamorphic grade.
The appearance, “face”, or “facies” of a metamorphic
rock depends on the assemblage (combination) of the
minerals that form at different pressures and
temperatures. There are 7 metamorphic facies that form
at different metamorphic grades.
Do you see the face in
this eclogite?
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Objective 5
I can relate metamorphic rock type, facies, and grade to different tectonic processes
There are 7 dominant mineral assemblages or metamorphic facies that
form under different metamorphic grades.
Team Points: Match 5 yellow trajectories below with the arrows indicating the
evolutionary paths of hypothetical rocks marked by the asterisks *.
Answers
1) near volcano (contact metamorphism)
2) subducting plate
3) mountain building
4) deep burial
5) accretionary prism
1)
2)
3)
5)
4)
Deep
Burial
Mountain
building
Near
volcano
*
*
*
*
*
Accretionary
prism
Subducting plate