rocks mineral mixtures. what are rocks? all natural rocks are aggregates of minerals the formation...
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Rocks
Mineral mixtures
What are rocks?What are rocks?
All natural rocks are aggregates of minerals
The formation of rocks and their physical properties are linked
All natural rocks are aggregates of minerals
The formation of rocks and their physical properties are linked
How and where do rocks form?
How and where do rocks form?
Many rocks originate from observable processes that take place at the Earth’s surface.
Rocks that do not appear to be like surface rocks give us clues to processes active within the Earth.
Many rocks originate from observable processes that take place at the Earth’s surface.
Rocks that do not appear to be like surface rocks give us clues to processes active within the Earth.
Rock ClassificationRock Classification
Rocks are classified according to the processes that form them.
1. Formed by the solidification of magma
2. The breakdown of pre-existing rock3. Solid state transformation of
minerals in a pre-existing rock.
Rocks are classified according to the processes that form them.
1. Formed by the solidification of magma
2. The breakdown of pre-existing rock3. Solid state transformation of
minerals in a pre-existing rock.
Three types of RocksThree types of Rocks Based on the processes of
formation three main categories of rocks are recognized:
1. Igneous2. Sedimentary3. Metamorphic
Based on the processes of formation three main categories of rocks are recognized:
1. Igneous2. Sedimentary3. Metamorphic
Igneous RocksIgneous Rocks Crystallized material from molten magma.
Volcanic processes = volcanic rocks “Beneath the crust” processes = plutonic rocks
Volcanic Rocks = extrusive Plutonic Rocks = intrusive
Crystallized material from molten magma. Volcanic processes = volcanic rocks “Beneath the crust” processes = plutonic rocks
Volcanic Rocks = extrusive Plutonic Rocks = intrusive
Cooling of MagmaCooling of MagmaRapid cooling of magma
(extrusive) normally produces rocks with small mineral grains
Slow cooling of magma (intrusive) normally produces rocks with large mineral grains
Rapid cooling of magma (extrusive) normally produces rocks with small mineral grains
Slow cooling of magma (intrusive) normally produces rocks with large mineral grains
Sedimentary RocksSedimentary Rocks
Deposition and precipitation of materials from the breakdown of older rocksOccurs on Earth’s surfaceWeathering can be:
Chemical – materials dissolve in waterPhysical – broken fragments (clasts)
Deposition and precipitation of materials from the breakdown of older rocksOccurs on Earth’s surfaceWeathering can be:
Chemical – materials dissolve in waterPhysical – broken fragments (clasts)
Deposition vs. Precipitation
Deposition vs. Precipitation
Clastic sediments can be lithified (cemented together) to form clastic sedimentary rocks Fragments are cemented with precipitates or simply
by compaction
Materials dissolved in water will precipitate when conditions are right to form chemical sedimentary rocks
Clastic sediments can be lithified (cemented together) to form clastic sedimentary rocks Fragments are cemented with precipitates or simply
by compaction
Materials dissolved in water will precipitate when conditions are right to form chemical sedimentary rocks
BeddingBeddingSedimentary rocks are recognized
by distinctive bedding or layeringBedding is a key feature in
recognizing paleo-environments
Sedimentary rocks are recognized by distinctive bedding or layering
Bedding is a key feature in recognizing paleo-environments
Metamorphic RocksMetamorphic Rocks
Either sedimentary or igneous rocks are transformed by processes occurring within the Earth’s crust.Increased pressureIncreased temperatureChemical reactions catalyzed by hot fluids
(water most often)
Either sedimentary or igneous rocks are transformed by processes occurring within the Earth’s crust.Increased pressureIncreased temperatureChemical reactions catalyzed by hot fluids
(water most often)
Types of Metamorphic Rocks
Types of Metamorphic Rocks
1. Regional Metamorphism Affecting vast areas Often at plate boundaries
2. Contact Metamorphism Very localized Occurs adjacent to volcanic or plutonic activity
1. Regional Metamorphism Affecting vast areas Often at plate boundaries
2. Contact Metamorphism Very localized Occurs adjacent to volcanic or plutonic activity
http://www.beavton.k12.or.us/greenway/leahy/00-01/rocks/gneiss.jpg
3. Hydrothermal Metamorphism Hot water flows through the rocks
causing a chemical reaction and thus modifying the properties
Often causes the precipitation of metal-ore deposits
3. Hydrothermal Metamorphism Hot water flows through the rocks
causing a chemical reaction and thus modifying the properties
Often causes the precipitation of metal-ore deposits
Minerals found in metamorphic rock depend on the minerals found in the parent rock. And the nature of the metamorphic processes. Similarities in appearance to sedimentary rocks and
igneous rocksBedding and banding at first glace look the sameMineral assemblage appears similar to igneous –
generally has more silicates
Minerals found in metamorphic rock depend on the minerals found in the parent rock. And the nature of the metamorphic processes. Similarities in appearance to sedimentary rocks and
igneous rocksBedding and banding at first glace look the sameMineral assemblage appears similar to igneous –
generally has more silicates
The Rock CycleThe Rock Cycle