Metamorophic Rock Flashcards
The change rocks go through when subjected to intense heat and pressure (without melting). Migrating fluids also play a role in their change of texture.
metamorphism
A parent rock of a metamorphic rock (un-metamorphosed compositional equivalent to the metamorphic rock).
protolith
All three of the main rock types (igneous,
sedimentary, and metamorphic) can become a _________.
metamorphic rock?
Describe how changing
pressure, and fluid content alter
existing rocks
Learning objective - general answer?
Characterize and name metmorphic rocks
rocks
Learning objective - general answer?
Determine the parent rocks of various metamorphic rocks
Learning objective - general answer?
Changes in temperatures
and pressures cause what to occur in rocks?
All minerals are stable at specific temperatures
and pressures.
they cause the atomic bonds in minerals to break and rearrange
The most common change caused by metamorphism
(Term & definition)
Recrystallization
Term for the metamorphic process that occurs when small crystals of one mineral slowly convert to larger and fewer crystals of the same mineral.
Recrystallization
Mineral composition can change when rocks recrystallize and form different minerals with the same chemical elements, a process called _______________.
neomorphism.
Recrystallization and neomorphism
do not involve _______________.
melting/p>
metamorphic rocks do not undergo ____________
melting
three processes that form metamorphic rocks
changes in pressure, changes in temperature, contact with hot fluid
Rocks that are adjacent to a lava or magma body experience intense heat and become changed. This process is commonly called _____________.
contact metamorphism
The closer the rock is to a heat source (lava or magma), the more heating and ________________
it experiences.
metamorphism occurs more when rocks are close to ______________ such as ______________
The conditions that create contact metamorphism can occur over a period as short as __________ to as long as ____________!
The conditions that create _______________ can occur over a period as short as several days to as long as thousands of years!
metamorphism
The change rocks go through when subjected to intense heat and pressure (without melting). Migrating fluids also play a role in their change of texture.
protolith
A parent rock of a metamorphic rock (un-metamorphosed compositional equivalent to the metamorphic rock).
Which rock types can become a metamorphic rock?
All three of the main rock types (igneous,
sedimentary, and metamorphic) can become a metamorphic rock.
Changes in what conditions cause the
atomic bonds in minerals to break and rearrange? Why?
Changes in temperatures and pressures
All minerals are stable at specific temperatures
and pressures.
Recrystallization
when small crystals of one mineral slowly convert to larger and fewer crystals of the same mineral.
Recrystallization is the ____________ change caused by metamorophism
most common
Recrystallization is caused by
metamorphism
changes in pressure, changes in temperature, contact with hot fluid
The above are _______________.
the three processes that form metamorphic rocks
neomorphism
when rocks recrystallize and form different minerals with the same chemical elements, which can change mineral composition
melting is not part of these two metamorphic processes
Recrystallization and neomorphism
changes in pressure, changes in temperature, contact with hot fluid are all _______________.
processes that form metamorphic rocks
contact metamorphism
a process that occurs in rocks that are adjacent to a lava or magma body, experience intense heat, and become changed.
The crystals in rocks that have been thermally metamorphosed grow in all
directions because
the pressure is equal in all directions.
The crystals in rocks that have been thermally metamorphosed grow in what directions? Why? How
all directions
the pressure is equal in all directions. Therefore, the crystals show no preferred orientation in
the rock.
How do crystals appear in thermally metamorphosed rock?
small - difficult to see with naked eye
An everyday example of thermal metamorphism is
the firing of clay pots to produce china.
the firing of clay pots to produce china. is an everyday example of
thermal metamorphism
Describe the process caused by the firing of clay pots in China
thermal metamorphism
The clay is composed of a mineral called kaolinite
(Al2Si2O5(OH)4), which loses the water in its crystal
structure during intense heating.
As a result, a new mineral called andalusite (Al2SiO5) is formed. The interlocking andalusite crystals are much
stronger and make porcelain china durable.
Hydrothermal Metamorphism
Another common type of contact metamorphism
Rocks that are created by reacting with hot fluids (like water)
Also called hydrothermally altered (or metasomatized) rocks.
Acommon type of contact metamorphism
Rocks that are created by reacting with hot fluids (like water)
Hydrothermal Metamorphism
Also called hydrothermally altered (or metasomatized) rocks.
Hydrothermal Metamorphism
Alternate terms for Hydrothermal Metamorphism
hydrothermally altered (or metasomatized) rocks.
Significant mineral changes can arise during hydrothermal alteration because
chemicals are added or lost in the rock.
Hydrothermal alteration can occur when
hot, waterrich
fluids separate from a magma body and penetrate
fractures in the surrounding rock body.
What can occur when hot, waterrich
fluids separate from a magma body and penetrate
fractures in the surrounding rock body?
Hydrothermal alteration can occur when
These fluids contain a variety of dissolved ions (Figure 2), and as the fluids cool in the fractures, new minerals precipitate. The resulting mineral-filled fractures are known as veins.
hot, waterrich
fluids separate from a magma body that penetrate
fractures in the surrounding rock body
What is contained in hot, waterrich
fluids that separate from a magma body and penetrate
fractures in the surrounding rock body
a variety of dissolved ions (Figure 2)
as the fluids cool in the fractures, new minerals precipitate. The resulting mineral-filled fractures are known as veins.
Figure 2: Hydrothermal vents, such as those found on the seafloor, are a source of
hydrothermal metamorphism
What is an oceanic source of hydrothermal metamorphism?
Hydrothermal vents, such as those found on the seafloor,
Figure 2 (Lab 5): A white smoker is shown here. The “smoke” is made up of dissolved minerals in the water. Select the image to enlarge.
What is the smoke of a vent in the ocean floor made of?
dissolved minerals in the water
See Figure 2 in Lab 5
An everyday example of hydrothermal alteration
commonly that occurs in the kitchen:
when you boil rice in salty water, it expands and tastes salty, because the rice is hydrothermally altered by the addition of two chemicals water
(H2O) and salt (NaCl).
What is this an example of?
when you boil rice in salty water, it expands and tastes salty
hydrothermal alteration
because the rice is hydrothermally altered by the addition of two chemicals water
(H2O) and salt (NaCl).
Rocks that are created by changes in pressure are known as
dynamically metamorphosed rocks
dynamically metamorphosed rocks
Rocks that are created by changes in pressure
Depending on their properties and the depth at which they are buried, minerals can either
break, or bend and flow under pressure.
Whether minerals break, or bend and flow under pressure depends on
their properties and the depth at which they are buried
Relatively rapid pressure changes occur along
major fault systems, like the ones that separate tectonic plates (e.g., the San Andreas fault)
What occurs along major fault systems, like the ones that separate tectonic plates (e.g., the San Andreas fault)?
Relatively rapid pressure changes
What happens to rocks that are caught in major fault systems near the surface of the earth?
they break and produce rocks that look powdery and broken, called cataclasites
They experience Relatively rapid pressure changes
At depth, what happens to rocks caught
in major fault systems
they break and flow
What is the appearance and name of rocks at depth caught in major fault systems?
produces rocks that look stretched out (like taffy)
called mylonites.
what is this image?
A thin section of a mylonite sample, showing a characteristic texture of stretched out grains that appear to
flow around rigid crystals.
What is the largest class of metamorphic rock?
that are created by all three processes: changes in temperature, pressure, and fluid composition. (Regional metamorphism - I think)
Where does regional metamorphism get its name?
Regional metamorphism occurs over a very large area, hence the name.
Which type of metamorphism occurs across large areas?
Regional metamorphism
What is another name for Regional Metamorphism? Why is it given this term?
This type of metamorphism is also called “dynamothermal”
because the rocks are being
- deformed (dynamic metamorphism) while they are
- recrystallizing (thermal metamorphism)
This type of metamorphism is also called “dynamothermal” because the rocks are being deformed (dynamic metamorphism) while they are recrystallizing (thermal metamorphism)
What is another name for Regional Metamorphism? Why is it given this term?
What is a real-world example of Regional Metamorphism?
A photograph of the Himalaya taken by the NASA Landsat 7 Satellite. Select the image to enlarge.
What can regional metamorphism be caused by?
This can be caused by
large igneous intrusions, which form and cool over thousands to tens-of-millions of years,
or by
extreme heat and pressure associated with tectonism, such as where two plates collide.
The cores of active mountain ranges, such as the Himalaya, undergo what process?
regional metamorphism.
What commonly occurs in areas experiencing regional metamorphism.
The folding of rock layers
The folding of rock layers commonly occurs in areas experiencing…
regional metamorphism
How does burial metamorphism occur?
through the formation and subsequent burial of sedimentary layers.
Reverse
this process occurs through the formation and subsequent burial of sedimentary layers. The sediments are subjected to low-grade (low temperature and low pressure) metamorphism.
How does burial metamorphism occur?
What is shock metamorphism?
Process that occurs when an extraterrestrial object crashes onto the surface of the Earth and alters the surrounding rock due to extreme pressure conditions.
Process that occurs when an extraterrestrial object crashes onto the surface of the Earth and alters the surrounding rock due to extreme pressure conditions.
What is shock metamorphism?
As rocks are buried, minerals that were stable on the surface, like clays and iron oxides, react to form….
different minerals that are stable under the new pressure
Some common metamorphic rock-forming minerals are:
Amphibole (Complex Silicate)
Garnet (Complex Silicate)
Quartz (SiO2)
Calcite (CaCO3)
Biotite: K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2
Plagioclase Feldspar (Na,Ca AlSi3O8 )
Chlorite (Mg,Fe)5Al(Si,Al)4O10(OH)8
Kyanite Al2SiO5
Dolomite Ca,Mg(CO3)2
Potassium Feldspar KAlSi3O8
Muscovite KAl2(AlSi3)O10(OH)2
Sillimanite Al2SiO5
*A full summary of common metamorphic rock-forming minerals and their physical properties is provided in Exercise 1.
Amphibole (Complex Silicate)
Garnet (Complex Silicate)
Quartz (SiO2)
Calcite (CaCO3)
Biotite: K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2
Plagioclase Feldspar (Na,Ca AlSi3O8 )
Chlorite (Mg,Fe)5Al(Si,Al)4O10(OH)8
Kyanite Al2SiO5
Dolomite Ca,Mg(CO3)2
Potassium Feldspar KAlSi3O8
Muscovite KAl2(AlSi3)O10(OH)2
Sillimanite Al2SiO5
*A full summary of common metamorphic rock-forming minerals and their physical properties is provided in Exercise 1.
Some common metamorphic rock-forming minerals are:
What are the two main types of textures in metamorphic rocks?
foliated and nonfoliated
foliated and nonfoliated
What are the two main types of textures in metamorphic rocks?
What type of appearance do foliated rocks have?
a layered appearance due to the parallel alignment of platy mineral crystals, such as micas.
a layered appearance due to the parallel alignment of platy mineral crystals, such as micas.
What type of appearance do foliated rocks have?
the planar feautures of rocks with a “layered appearance” due to the parallel alignment of platy mineral crystals
foliation
foliation
the planar feautures of rocks with a “layered appearance” due to the parallel alignment of platy mineral crystals
micas are an example of what types of metamorphic rock?
foliated rocks
Foliation occurs as a result of _________ and _________ and resembles ___________.
pressure and recrystallization (from heating). If a rock contains foliation, it suggests that the stress in one dimension was much greater than in the other two. The resulting texture resembles a deck of cards
Name the specific types of foliated textures, in order of increasing metamorphic grade (increasing temperature and pressure conditions).
- Slate
- Phyllite
- Schist
- Gneiss
- Slate
- Phyllite
- Schist
- Gneiss
Name the specific types of foliated textures, in order of increasing metamorphic grade (increasing temperature and pressure conditions).
slaty rock cleavage
A type of foliation of metamorphic rocks
the lowest metamorphic grade (least temperature/pressure) – or a very low grade
displays a very flat foliation along closely spaced (microscopic) shear planes.
The metamorphic rock slate has this texture (Figure 3).
A type of foliation of metamorphic rocks
the lowest metamorphic grade (least temperature/pressure) – or a very low grade
displays a very flat foliation along closely spaced (microscopic) shear planes.
The metamorphic rock __________ has this texture (Figure 3 - attached).
slaty rock cleavage
Phyllite (Phyllitic Texture)
a type of foliation of metamorphic rocks
A metamorphic rock with a phyllitic texture contains
wavy or wrinkled foliations.
usually have a pseudometallic luster from the abundance of mica (Figure 4), commonly muscovite or chlorite.
Rocks with this texture are called phyllite.
A phyllite is a low grade metamorphic rock, meaning it experienced moderate temperatures and pressures during metamorphism.
a type of foliation of metamorphic rocks
A metamorphic rock with a phyllitic texture contains
wavy or wrinkled foliations.
usually have a pseudometallic luster from the abundance of mica (Figure 4), commonly muscovite or chlorite.
a low grade metamorphic rock, meaning it experienced moderate temperatures and pressures during metamorphism.
Phyllite (Phyllitic Texture)
Schist/Schistocity
Schistosity describes metamorphic rocks with glittery, scaly layering of large platy minerals, commonly muscovite and chlorite (Figure 5).
The term can also describe the linear alignment of long prismatic crystals, such as kyanite or tourmaline, causing the rock to resemble a bundle of toothpicks (e.g., when viewed from one side you see lines, but when viewed from perpendicular you see dots).
Rocks with this texture are called schist.
A schist is a medium grade metamorphic rock, meaning it experienced fairly high temperatures and pressures during metamorphism.
describes metamorphic rocks with glittery, scaly layering of large platy minerals, commonly muscovite and chlorite (Figure 5).
The term can also describe the linear alignment of long prismatic crystals, such as kyanite or tourmaline, causing the rock to resemble a bundle of toothpicks (e.g., when viewed from one side you see lines, but when viewed from perpendicular you see dots).
a medium grade metamorphic rock, meaning it experienced fairly high temperatures and pressures during metamorphism.d
Schist/Schistocity
Gneissic banding/Gneiss
is present when minerals have separated into distinct layers or lenses (Figure 6).
This looks like alternating light and dark, and medium- to coarse-grained bands.
The light bands are usually composed of quartz, feldspars, or carbonate minerals such as calcite or dolomite.
Rocks that display this texture are called gneiss (pronounced “nice”).
A gneiss is a high grade foliated metamorphic rock, meaning it experience very high temperatures and pressures during metamorphism.
is present when minerals have separated into distinct layers or lenses (Figure 6).
This looks like alternating light and dark, and medium- to coarse-grained bands.
The light bands are usually composed of quartz, feldspars, or carbonate minerals such as calcite or dolomite.
a high grade foliated metamorphic rock, meaning it experience very high temperatures and pressures during metamorphism.
Rocks that display this texture are called .______________
Gneissic banding/Gneiss
Nonfoliated
a Metamorphic Rock Texture
these metamorphic rocks have no visible layering
They may, however, exhibit characteristics like sheared grains and other types of textures
a Metamorphic Rock Texture
these metamorphic rocks have no visible layering
They may, however, exhibit characteristics like sheared grains and other types of textures
Nonfoliated
Metamorphic rocks with a crystalline texture
a type of nonfoliated metamorphic rock
display aggregates of visible, inter-grown crystals that are usually equal-sized.
The crystals are medium- to coarse-grained.
One type of metamorphic rock that has this texture is marble.
a type of nonfoliated metamorphic rock
display aggregates of visible, inter-grown crystals that are usually equal-sized.
The crystals are medium- to coarse-grained.
One type of metamorphic rock that has this texture is marble.
Metamorphic rocks with a crystalline texture
Microcrystalline Texture
texture type of a nonfoliated metamorphic rock
A metamorphic rock with this texture contains aggregates of intergrown crystals that are very fine-grained (usually not visible with the naked eye).
An example of a rock with a microcrystalline texture is hornfels.
texture type of a nonfoliated metamorphic rock
A metamorphic rock with this texture contains aggregates of intergrown crystals that are very fine-grained (usually not visible with the naked eye).
An example of a rock with this texture is hornfels.
Microcrystalline Texture
Sandy Texture
a texture type of nonfoliated metamorphic rocks
A metamorphic rock with this texture contains medium- to coarse-grained aggregates of fused quartz grains that look similar to a sandstone.
This type of rock is called quartzite (Figure 9).
a texture type of nonfoliated metamorphic rocks
A metamorphic rock with this texture contains medium- to coarse-grained aggregates of fused quartz grains that look similar to a sandstone.
This type of rock is called quartzite (Figure 9).
Sandy Texture
Glassy texture
a subtype of nonfoliated rock textures
A metamorphic rock with this texture looks like a homogenous mass with no visible grains or foliation.
These rocks break in a way that resembles conchoidal fracture with glossy surfaces.
An example of a rock with a glassy texture is anthracite, a type of coal.
a subtype of nonfoliated rock textures
A metamorphic rock with this texture looks like a homogenous mass with no visible grains or foliation.
These rocks break in a way that resembles conchoidal fracture with glossy surfaces.
An example of a rock with a glassy texture is anthracite, a type of coal.
Glassy texture
other characteristics that can occur in either foliated or nonfoliated metamorphic rocks
Examples include stretched or sheared grains, hydrothermal veins, folds (e.g., bends in rock layers), and lineations (e.g., lines on rock edges or surfaces).
stretched or sheared grains
hydrothermal veins
folds (eg., bends in rock layers)
lineations (lines on rock edges or surfaces
stretched or sheared grains
hydrothermal veins
folds (eg., bends in rock layers)
lineations (lines on rock edges or surfaces
other characteristics that can occur in either foliated or nonfoliated metamorphic rocks
Examples include stretched or sheared grains, hydrothermal veins, folds (e.g., bends in rock layers), and lineations (e.g., lines on rock edges or surfaces).
Figure 11: Describe what this depicts
Figure 11: A summary illustration of several types of metamorphic rocks and their parent rocks in a regional metamorphism environment.
the regional metamorphism of several sedimentary rocks.
The sandstone is metamorphosed to quartzite (a nonfoliated rock), and
the limestone is metamorphosed to marble (also a nonfoliated rock).
The shale shows an increasing grade of metamorphic rocks (from slate to gneiss) with increasing temperature and pressure.
The zone immediately surrounding the granite intrusion contains rocks that have undergone contact metamorphism.
Figure 11: Draw/Label A summary illustration of several types of metamorphic rocks and their parent rocks in a regional metamorphism environment.
the regional metamorphism of several sedimentary rocks.
The sandstone is metamorphosed to quartzite (a nonfoliated rock), and
the limestone is metamorphosed to marble (also a nonfoliated rock).
The shale shows an increasing grade of metamorphic rocks (from slate to gneiss) with increasing temperature and pressure.
The zone immediately surrounding the granite intrusion contains rocks that have undergone contact metamorphism.
Figure 11: Describe what this depicts
Two ways that metamorophic rocks are classified
used not only to name metamorphic rock, but also to determine their protolith
texture & minerology
texture & minerology
Two ways that metamorophic rocks are classified
used not only to name the rock, but to determine its protolith
Fill in the protoliths in the following table:
Answer Table
Fill in the distinctive features in the following table:
Answer table
Fill in the grain size in the following table:
answer table
Fill in the grades in the following table:
Answer table:
Fill in the rock names in the following table:
Table answers:
Fill in the rock names in the following table:
Answer table:
Fill in the protoliths in the following table:
Answer table:
Fill in the grain size in the following table:
Answer table:
Fill in the features in the following table:
Answer table:
What type of rocks does the following table depict?
Nonfoliated metamorphic rocks
What type of rocks does the following table depict?
Foliated metamorphic rocks
Limestone is protolith of
Marble’s protolith
Marble’s protolith
Limestone is protolith of
