the story of rocks how did all of these rocks get here?
Post on 16-Dec-2015
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The Story of RocksThe Story of RocksHow did all of these
rocks get here?
Rock typesRock typesRock types are based on the way the rocks formed!
• Igneous
• Sedimentary
• Metamorphic
Rock types are based on the way the rocks formed!
• Igneous
• Sedimentary
• Metamorphic
IgneousIgneousIgneousIgneousThese rocks are formed from molten or These rocks are formed from molten or liquid rock.liquid rock.
Magma = liquid rock inside the EarthMagma = liquid rock inside the Earth
Lava = liquid rock on the surface.Lava = liquid rock on the surface.
SedimentarySedimentaryThese rocks are made of small fragments of These rocks are made of small fragments of rock cemented togetherrock cemented together
The small fragments are broken down from The small fragments are broken down from larger rocks by wind, water, and other forces and larger rocks by wind, water, and other forces and carried away.carried away.
Later they are deposited, buried deeper and Later they are deposited, buried deeper and deeper until they are compacted into rock.deeper until they are compacted into rock.
MetamorphicMetamorphicThese rocks start as igneous or These rocks start as igneous or sedimentary rocks.sedimentary rocks.
Rocks are changed by:Rocks are changed by:
1) heat1) heat
2) pressure2) pressure
3) chemical processes3) chemical processes
SedimentaryRocks
MetamorphicRock
MagmaIgneous
Rock
Sediments
Rock CycleRock Cycle
SedimentaryRocks
MetamorphicRock
MagmaIgneous
Rock
Sediments
Rock CycleRock Cycle
Igneous Rocks
Igneous RocksIgneous RocksThe main property of igneous rocks that allows us to identify which type of igneous rock that we have is – Texture
The texture is based on how large the crystals.
Crystal size depends on how fast the rock cooled (i.e. cooling rate)
Igneous Rocks
Igneous Rocks
Igneous RocksIgneous Rocks
Igneous RocksIgneous Rocks
Igneous RocksIgneous Rocks
Igneous RocksIgneous Rocks
Igneous Rocks
Sedimentary RocksSedimentary Rocks
Sedimentary RocksSedimentary RocksThe main property that allows us to group sedimentary rocks is the source of sediments.
Sediments can be:
1. Clastic
2. Chemical
3. Organic
The main property that allows us to group sedimentary rocks is the source of sediments.
Sediments can be:
1. Clastic
2. Chemical
3. Organic
Sedimentary RocksSedimentary Rocks• Clastic – These sediments are composed of
fragments that can be up to a meter in diameter or so small that the fragments cannot be seen with the naked eye.
• Clastic – These sediments are composed of fragments that can be up to a meter in diameter or so small that the fragments cannot be seen with the naked eye.
Sedimentary RocksSedimentary RocksChemical – These fragments were dissolved in water and usually form at the bottoms of rivers, lakes, seas, and oceans
Chemical – These fragments were dissolved in water and usually form at the bottoms of rivers, lakes, seas, and oceans
Sedimentary RocksSedimentary RocksOrganic – These fragments are from organic material like animals and plantsOrganic – These fragments are from organic material like animals and plants
Sedimentary RocksSedimentary Rocks• Common sedimentary features:
– Stratification (layering)– Ripple marks (from waves)– Cross bedding (different direction of beds)– Mud cracks (dried mud)– fossils (lithified animals and plants)– concretions
• Common sedimentary features:– Stratification (layering)– Ripple marks (from waves)– Cross bedding (different direction of beds)– Mud cracks (dried mud)– fossils (lithified animals and plants)– concretions
Sedimentary RocksSedimentary Rocks• Stratification• Stratification
Sedimentary RocksSedimentary Rocks• Ripple marks• Ripple marks
Sedimentary RocksSedimentary Rocks• Cross bedding• Cross bedding
Sedimentary RocksSedimentary Rocks• Mud Cracks• Mud Cracks
Sedimentary RocksSedimentary Rocks• Fossils• Fossils
Metamorphic RocksMetamorphic Rocks
Metamorphic RocksMetamorphic RocksMetamorphic rocks began their life as an igneous or sedimentary rock but underwent a physical change to become a new type of rock.
What causes the changes?1. Heat2 Pressure3. Chemicals
Metamorphic RocksMetamorphic RocksThere are two basic types of metamorphism:
1. Contact Metamorphism
2. Regional metamorphism
Metamorphic RocksMetamorphic RocksContact Metamorphism
Occurs when rocks near a magma chamber are exposed to high levels of heat but not melted
Metamorphic RocksMetamorphic RocksRegional Metamorphism
Occurs when rocks are exposed to tectonic pressure or heat.
Metamorphic RocksMetamorphic Rocks
Metamorphic RocksMetamorphic RocksHow do we classify metamorphic rocks since they have a wide range of compositions and origins?
Foliation!!
Definition: Visible parallel bands
(not layers)
Metamorphic rocks are foliated or unfoliated
Metamorphic RocksMetamorphic Rocks
Foliation occurs because the mineral grains are squished by the intense heat or pressure
Metamorphic RocksMetamorphic Rocks
Metamorphic RocksMetamorphic Rocks
Metamorphic RocksMetamorphic RocksUnfoliated
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