Download Rocks

Rock Cycle
• Magma- Molten rock below the
surface of the Earth
• Lava- Molten rock above the Earth’s
surface
• Crystallization- When magma cools
and forms igneous rock
Rock Cycle
• WeatheringWhen rock is
broken down
into smaller
particles
– Forms small
particles called
sediment
Rock Cycle
• Lithification- Conversion into
rock from sediment
• Metamorphism- Conversion of
sedimentary rock to metamorphic
rock through heat and pressure
Rock cycle
• Melting- Conversion of rock
back into magma
Rock Cycle
Types of Rock
• Igneous rock- Rock formed directly
from cooling magma
–Extrusive rock- Rock formed outside
of the surface of the Earth- Basalt
–Intrusive rock- Formed within the
Earth- Granite
Classifying
Igneous Rock
• Texture- Size and arrangement of
crystals
–Slow cooling rock- Larger crystals
–Fast cooling rock- Smaller crystals
Classifying Igneous
Rock
–Coarse grained textureIntergrown crystals of equal
size
• Granite
–Porphyritic texture- Large
crystals imbedded in
smaller crystals
Classifying
Igneous Rock
• Glassy- Smooth, even texture similar
to glass
–Obsidian
Mineral
composition
• Different minerals crystallize
at different temperatures and
will form rocks with varying
mineral composition
Bowen Reaction
Series
• Outlines the order of
crystallization of different
minerals in the magma of the
Earth
Naming Igneous
Rocks
• Igneous rocks are named for
the texture and mineral
composition of the rock
Sedimentary
Rocks
• Sediments are turned to rock by
compaction and cementation
Sedimentary Rock
• Erosion- When natural forces
loosen and carry away fragments
of rocks
• Deposition- When sediment settles
out of water or wind to form a
layer of sediment
Sedimentary Rock
• Compaction- Particles moving
closer together by the weight of
other sediment on top
• Cementation- “gluing” of
sediment by minerals deposited by
ground water
Types of
Sedimentary Rock
• Detrital/ Clastic- Rock formed from
solid particles of weathered rock
• Chemical - Precipitates of chemically
eroded sediment
• Organic- Sedimentary rock made up
of once living things
Detrital
Sedimentary Rock
• Made of various size particle
–Geologists use sediment size
when classifying detrital
sedimentary rock
Detrital
Sedimentary Rock
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Boulder> 256 mm
Cobble= 64-256 mm
Pebble= 4-64 mm
granule= 2-4 mm
Sand = 1/16-2 mm
Silt= 1/256 - 1/16
Clay= 1/256
Chemical
Sedimentary Rock
• When substances dissolved in
water are deposited through
evaporation, precipitation, or
chemical conversion from
substance to another
Chemical
Sedimentary Rock
• Evaporites- Rock deposited by
evaporation- Salt
–Rock Salt is used to make glass, paper,
soap and dairy products
• Heat and pressure- Organic matter
that is transformed- Coal
Organic
• Coal- Rock made from
compressed and heated plant an
animal material
• Limestone- Rock made from
shells of once living organisms
Coal Formation
• Peat- partially altered plant materialLow energy
• Lignite- Soft brown coal- Moderate
energy
• Bituminous coal- Soft black coalHigh energy
• Anthracite- Hard, black coal- High
energy
Features of
Sediment
• Deposited in strata or bedsLayers of rock laid down at
separate times and lithified into
rock
Features of
Sedimentary Rock
• Contain fossils of ancient organisms
• Contain records of the types of life,
climate, and conditions in an area at
certain times in history
Types of
sedimentary rock
• Sandstone- Compressed sand
• Shale- Compressed swamp or bog
organic material
• Conglomerate- Rock formed from
stream bed material
• Coquina- Formed from shell material
near the ocean
Coral Reefs
• Skeletons of coral that build up to
form a reef in shallow warm seas.
• Skeletons build up on one another
as corals die and other corals build
on top of them.
Coral Reefs
• Atoll- A ring shaped coral
reef that forms around a
volcanic island far from land.
Limestone from coral
reefs
• As coral reefs build the old coral
becomes limestone which over
millions of years uplift to form
continental limestone
Metamorphic
Rock
• Rock that has
been changed as a
result of heat and
pressure from one
rock form to
another
Metamorphic
Rock
• Can be derived from igneous,
sedimentary, or other
metamorphic rock
Metamorphism
• Low grade- Slight changes occur
in the rock
• High grade- Massive changes
occur
Types of
Metamorphism
• Regional metamorphism- Occurs
over a large area during mountain
building or other High energy
situation
Types of
Metamorphism
• Contact metamorphism- When
rock comes in contact with
magma and is sub sequentially
changed into another form.
Classifying
metamorphic rock
• Foliated- Fine grained, cleaves
easily- Slate
–Schists- Strongly foliated
–Gneiss- Banded foliated rock
Classifying
metamorphic rock
• Nonfoliated Rock- Interlocking
crystals
–Marble- Metamorphosis of
limestone
–Quartzite- Metamorphosis of
quartz crystals