Today:
1) Quiz: Metamorphism/Weathering and Sedimentary Rock Review
2) Metamorphism and Metamorphic Rocks
3) In-class exercise Metamorphic Rocks
4) Swiss Alps Movie (45 min)
Next Wednesday
6) Exam2
Think outside
the Box!
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Metamorphism
Meta- Greek word, meaning Change.
Morph is from the Greek morphe meaning shape or form
ism- the action or result of
Metamorphic Rock- forms when preexisting rock (parent
rock), or protolith undergoes solid state change in response to
the modification of its environment
.
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The Rock Cycle
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Causes of Metamorphism
Metamorphism due to heating (200 - 800 C)
Metamorphism due to increased Pressure
Metamorphism due to increase Heat and Pressure
Metamorphism due to Hydrothermal Fluids
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Thursday, November 7, 13
Where Metamorphic Rocks Form
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Where Metamorphic Rocks Form
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Where Metamorphic Rocks Form
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Where Metamorphic Rocks are Exposed
Least abundant rock
at the Earths
Surface
Form at Temp
200-800 C and
depths greater than
5km
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Where Metamorphic Rocks are Exposed
Least abundant rock
at the Earths
Surface
Form at Temp
200-800 C and
depths greater than
5km
However, the continental
curst is predominately
composed of
metamorphic rocks
which underlie a thin
veneer of sedimentary
rocks
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Where Metamorphic Rocks are Exposed
Least abundant rock
at the Earths
Surface
Form at Temp
200-800 C and
depths greater than
5km
However, the continental
curst is predominately
composed of
metamorphic rocks
which underlie a thin
veneer of sedimentary
rocks
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2 Types of Metamorphic Rocks
Foliated(layered)
and
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Non-Foliated
2 Types of Metamorphic Rocks
Foliated(layered)
and
Non-Foliated
What are the three main factors
controlling the type of Metamorphic
Rock that develops?
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Thursday, November 7, 13
2 Types of Metamorphic Rocks
Foliated(layered)
and
Non-Foliated
What are the three main factors
controlling the type of Metamorphic
Rock that develops?
Temperature Pressure Composition
and Presence of Water
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Protolith = Composition
Proto- means first in time; original.
lith is the Greek word for stone
Protolith refers to the original rock before metamorphism it
could be an igneous, sedimentary, or another metamorphic
rock.
Thursday, November 7, 13
Protolith = Composition
Proto- means first in time; original.
lith is the Greek word for stone
Protolith refers to the original rock before metamorphism it
could be an igneous, sedimentary, or another metamorphic
rock.
Igneous- Pretty Good Diet Granola BAR
Thursday, November 7, 13
Protolith = Composition
Proto- means first in time; original.
lith is the Greek word for stone
Protolith refers to the original rock before metamorphism it
could be an igneous, sedimentary, or another metamorphic
rock.
Igneous- Pretty Good Diet Granola BAR
Sedimentary- Conglomerate,
Sandstone, mud/claystone,
limestone
Thursday, November 7, 13
Protolith = Composition
Proto- means first in time; original.
lith is the Greek word for stone
Protolith refers to the original rock before metamorphism it
could be an igneous, sedimentary, or another metamorphic
rock.
Igneous- Pretty Good Diet Granola BAR
Sedimentary- Conglomerate,
Sandstone, mud/claystone,
limestone
Metamorphic
Thursday, November 7, 13
Generalized Mineral Stability
for Different Metamorphic Grades
Igneous- Pretty Good Diet Granola BAR
Sedimentary- Conglomerate,
Sandstone, mud/claystone,
limestone
Thursday, November 7, 13
Generalized Mineral Stability
for Different Metamorphic Grades
Thursday, November 7, 13
Generalized Mineral Stability
for Different Metamorphic Grades
Igneous- Pretty Good Diet Granola BAR
Thursday, November 7, 13
Generalized Mineral Stability
for Different Metamorphic Grades
Igneous- Pretty Good Diet Granola BAR
Sedimentary- Conglomerate,
Sandstone, mud/claystone,
limestone
Thursday, November 7, 13
2 Types of Metamorphic Rocks
Foliated(layered)
and
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Non-Foliated
2 Types of Metamorphic Rocks
Foliated(layered)
and
Non-Foliated
Temperature Pressure Composition
and Presence of Water
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Non-Foliated Metamorphic Rocks
Protolith
Sandstone
Meta Rx
Quartzite
Limestone
Marble
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Calcite
Non-Foliated Metamorphic Rocks
Meta Rx
Greenstone
Protolith
Basalt
Epidote
Actinolite
Chlorite
Medium-Grade
G
h
g
Hi
Plagioclase Feldspar
Very
High
Grade
Eclogite
Pyroxene
Garnet
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Blue Schist
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Calcite
e
d
a
r
Generalized Mineral Stability
for Different Metamorphic Grades
Thursday, November 7, 13
Generalized Mineral Stability
for Different Metamorphic Grades
Igneous- Pretty Good Diet Granola BAR
Thursday, November 7, 13
Generalized Mineral Stability
for Different Metamorphic Grades
Igneous- Pretty Good Diet Granola BAR
Sedimentary- Conglomerate,
Sandstone, mud/claystone,
limestone
Thursday, November 7, 13
Foliated
Metamorphic
Rocks
Sedimentary
Parent/Protolith
Mudstone/shale
Small Muscovites
Slate
Kaolinite clay
Text
Grain size
Increasing
Phyllite
Muscovite, Garnet, Kyanite
Mineral
Differentiation
Schist
Bigger Muscovites
Gneiss
Garnet Quartz, K-spar
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Degree of Metamorphism Increasing No Melting!
Thursday, November 7, 13
Metamorphic Rock Stability Diagram
Does anything look familiar here?
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Metamorphic Rock Stability Diagram
Melting Curves
Solidi for Granite and Basalt
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Metamorphic Rock Stability Diagram
?
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Causes of Metamorphism
Metamorphism due to heating (200-800 C)
Metamorphism due to increased Pressure
Metamorphism due to increase Heat and Pressure
Metamorphism to Hydrothermal Fluids
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Increased Heat and Pressure
?
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Increased Heat and Pressure
?
Burial by sedimentation - Burial by tectonics
Hydrostatic stress
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Deep Burial by accumulation of thick
sequences of sedimentary rock
10 km of sediment
4 km of sediment
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Deep Burial by accumulation of thick
sequences of sedimentary rock
10 km of sediment
Hydrocarbon Generation
4 km of sediment
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Dynamo-thermal Metamorphism
Asia
India
50 Ma
Present
Himalayan Mountains
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Himalayan Metamorphic
core
India
70-80 km thick Crust
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Asia
Himalayan Metamorphic core
India
70-80 km thick Crust
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Thursday, November 7, 13
Asia
Himalayan Metamorphic core
India
70-80 km thick Crust
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Asia
Where Metamorphic Rocks Form
Asia
Indian continent
Indian continent
Bonnet et al. (2007) video
Thursday, November 7, 13
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Asia
Where Metamorphic Rocks Form
Asia
Indian continent
Indian continent
Bonnet et al. (2007) video
Thursday, November 7, 13
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Asia
Metamorphic Mineral Stability Diagram
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Earth’s Temperature Profile is Variable
Slate
Phyllite
Gneiss
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Thursday, November 7, 13
Earth’s Temperature Profile is Variable
Slate
Phyllite
Gneiss
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Metamorphic Mineral Phase Diagram
Slate
Phyllite
Green schist
Gneiss
Amphibolite
Hornblende, Garnet
Schist
Blue schist
Eclogite
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Gneiss
Causes of Metamorphism
Metamorphism due to heating (200-800 C)
Metamorphism due to increased Pressure
Metamorphism due to increase Heat and Pressure
Metamorphism to Hydrothermal Fluids
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Thermal or Contact Metamorphism
Contact metamorphism
typically produces
a fine-grained
metamorphic rock
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Metamorphic Rock Stability Diagram
What kind of metamorphic Rock might you expect from
Contact metamorphism?
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Thursday, November 7, 13
Metamorphic Rock Stability Diagram
What kind of metamorphic Rock might you expect from
Contact metamorphism?
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Thermal or Contact Metamorphism
Skarn
When hydrothermal
fluids are present
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Causes of Metamorphism
Metamorphism due to heating (200-800 C)
Metamorphism due to increased Pressure
Metamorphism due to increase Heat and Pressure
Metamorphism to Hydrothermal Fluids
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Hydrothermal Alteration
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Hydrothermal
Alteration
mantle
peridotite
Serpentinite
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12% H2O by mass
olivine
Serpentine
Magnetite
Hydrothermal
Alteration
Black
Smokers
olivine
Thursday, November 7, 13
Serpentine
Magnetite
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Causes of Metamorphism
Metamorphism due to heating (200-800 C)
Metamorphism due to increased Pressure
Metamorphism due to increase Heat and Pressure
Metamorphism to Hydrothermal Fluids
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Differential Stress and Development of
Preferred Mineral Orientation
Directed Pressure
Shearing
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Tectonic Fabric
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Tectonite
Axial Planar
Cleavage
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Other cool rocks that have something to say!
Tectonites
Shearing
Shortening
Extension
Shortening
Shearing
Extension
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Today:
1) Case Study: Contact Metamorphism
2) Metamorphic Rx Identification (9:50)
3) Movie: The Alps (10:10)
Next Class:
4) Exam2
-Minerals, Igneous Rx,Volcanoes,
Weathering, Sedimentary Rx,
Metamorphic Rx
Think inside the Box! 49
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Case Study : Contact Metamorphism
Sierra Nevada of California
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Sierra Nevada of California
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Sierra Nevada of California
Migmatite
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Sierra Nevada of California
Migmatite
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Stretch Pebble Conglomerate