Lesson 9: Metamorphic Rocks Flashcards
Metamorphism
Transform
Metamorphic grade
the degree that the parent rock changes during metamorphism
Metamorphic agents:
- Temperature
- Pressure
- Hot fluids
How does temperature and pressure affect metamorphism?
low temperatures and pressures have a low metamorphic grade.
high temperatures and pressure have a high metamorphic grade.
Compare the metamorphic textures.
Foliated: when differential stress causes the platy mineral crystals to slide parallel to and past one another
Non-foliated: crystalline texture
What are the 4 types of foliated metamorphic rocks?
- Slate - rock splits into thin sheets
- Phyllite - wavy and/wrinkled; with a satiny or metallic luster
- Schist - platy minerals are discernible with the naked eye
- Gneiss - dark and light bands that does not split as easily as the other foliated rocks
What are the 3 types of non-foliated metamorphic rocks?
- Quartzite - sandy texture
- Marble - crystalline texture
- Hornfels - fine-grained
What is a protolith?
The original parent rock
What are the protoliths of marble?
Limestone
Dolostone
What is the protolith of quartzite?
Quartz sandstone
What is the protolith of slate?
Shale
What is the protolith of phyllite?
Shale
What is the protolith of schist?
Shale
What is the protolith of gneiss?
Shale
What are the metamorphic environments? (5)
- Contact/thermal metamorphism
- Hydrothermal metamorphism
- Burial metamorphism
- Subduction zone metamorphism
- Regional metamorphism
What is mylonite?
Rocks formed in regions where minerals form a foliated or lineated appearance
What is impact metamorphism?
What occurs when asteroids/comets strike the Earth’s surface which produces fused fragmented rock plus glass-rich ejecta that resemble volcanic bombs.
A metamorphosed equivalent of a limestone would be a ___.
marble
Gneiss _____________.
shows dark and light bands of minerals.
A place where rocks are probably being subjected to contact metamorphism.
A mile under St Helens
Which of the following metamorphic rocks displays a foliated texture?
a. marble
b. quartzite
c. schist
d. hornfels
c. schist
Which of the following is not a useful metamorphic mineral?
a. quartz; used to make glass
b. diamond; used to make saw blades, drill bits, and gemstones
c. graphite; used in lubrication and to make pencil leads
d. garnet; used in abrasives and to make gemstones
a. quartz; used to make glass
Which of the following is not an agent of metamorphism?
a. gravity
b. heat
c. pressure
d. fluid activity
a. gravity
The original (parent) rock that has undergone metamorphism is called the _____.
protolith
Which foliated texture would be most likely to develop in beds of shale with low-grade metamorphism?
a. schistosity
b. fissility
c. gneissic branding
d. slaty cleavage
d. slaty cleavage
What is a common parent rock of slate?
a. granite
b. shale
c. limestone
d. conglomerate
b. shale
___ ______ produces the greatest quantity of metamorphic rock.
regional metamorphism
