Igneous Rock Born of Fire Origin of Igneous Rock Magma cools and forms various types of igneous rock Depends on composition and time it takes to cool Freezes to form igneous rock Freeze between 700C and 1250C ID: 289097
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Slide1
RocksSlide2
Igneous Rock
Born of FireSlide3
Origin of Igneous Rock
Magma cools and forms various types of igneous rock
Depends on composition and time it takes to cool
“Freezes” to form igneous rock.
Freeze between 700°C and 1,250°C
1,290°F to 2282°FSlide4
Magma forms by:
Temperature- increased temperature deep inside the Earth
Different minerals melt at different temperatures
Pressure- high pressure forces minerals to stay solid
When rises to shallow depths, pressure released and melts
Composition-water and CO
2
enter rock close to melting point
Lower melting pointSlide5
Composition and Texture
Light colored rocks less dense-
Felsic
silicon, aluminum, sodium, potassium
Dark colored rocks more dense-
Mafic
Iron, magnesium, calcium
Time to cool determines texture
Longer time to cool, more time for crystals to grow
Coarser textureSlide6
Formations
Intrusive Igneous Rock
Cools beneath Earth’s surface
Coarse grained texture
Well insulated- cools slow
Plutons
- balloon shaped, formed when magma cools at great depths
Plutonic rock- Intrusive rockSlide7
Extrusive Igneous Rock
Forms on the Earth’s surface
C0ols quickly
Small crystals or none at all
Lava flowSlide8
Sedimentary RockSlide9
Origin of Sedimentary Rock
Rocks are weathered
Wind, water, ice, sunlight, gravity
Sediments formed
Transported by erosion
Deposited in layers
Compacted and compressed
Dissolved minerals separate out of the water to form a natural glueSlide10
Forms at or near the surface
Features tell history
Strata layersSlide11
Composition
3 categories
Clastic
-rock or mineral fragments, called
clasts
, stick together, made of other rocks and minerals
Chemical-forms from solutions of minerals and water
Dissolved materials form minerals that make up sedimentary rocks
Limestone made of CaCO
3
Organic-forms from remains of living organisms
Coral and shells
Fossiliferous
Limestone
Fossils are the remains or traces of plants and animalsSlide12
Fossiliferous
limestone
Conglomerate
LimestoneSlide13
Structure
Stratification- layering
Strata differ due to:
Kind
Size
Color
Rate affects thickness
Record wind motion and water wavesSlide14
Metamorphic RockSlide15
Origin
Change when surroundings change
Temperature and pressure
Increased pressure at 2 km below the surface
Temperature- 50°C to 1,000°C
Metamorphism does not melt rockSlide16
Contact Metamorphism
Come into contact with magma
As magma moves, heats up surrounding rock, “cooks” it
Happens next to igneous intrusions
Regional Metamorphism
When large pieces of rock collide under other rock formations
Deformed and chemically changed
Mostly under continental rock formationsSlide17Slide18
Composition
In new environment, no longer stable
Change into minerals that are stable at the new temperature and pressure
Scientists can estimate the temperature and depth (pressure)Slide19
Texture
Foliated- aligned; look like pages of a book
Flat minerals
Metamorphic rock changes to other metamorphic rock
Increased heat and pressure causes coarse-grained
Nonfoliated
- no regular pattern
Minerals not
allignedSlide20
Gneiss- high grade
Slate- low gradeSlide21
Hornfels