Geology Test 1
Terms
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- Catastrophism is...
- The concept that earth was shaped by catastrophic events of a short-term nature
- Hutton's idea of Earth's uniformitarianism is that...
- physical, chemical and biological laws that operated in the past also operate today
- Law of Superposition
- In any undeformed sequence of sedimentary rocks, each bed is older than the one above and younger than the one below.
- 3 Types of Rock
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Igneous
Sedimentary
Metamorphic - Structure of the Earth (3 main components)
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1. Crust
2. Mantle
3. Core - 5 Main Layers of the Earth
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1. Lithosphere
2. Asthenosphere
3. Mesosphere
4. Outer Core
5. Inner Core - Mantle (properties)
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Composed of dense materials
(olivene, pyroxcene) - Crust (properties)
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The thin, outermost layer of Earth.
-Divided into Oceanic and Continental crust - Oceanic Crust (properties)
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- 1-10 km thick (avg. 5 km)
- Relatively heavier; more dense
- Made of Basalt - Continental Crust (properties)
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- 10-70 km thick (avg 35 km)
- Relatively lighter; less dense - Core (properties)
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The innermost layer of earth based on composition
-Largely an iron-nickel alloy with small amounts of oxygen, silicon, and sulfur - Lithosphere (properties)
- The rigid outer layer of earth, including the crust and upper mantle
- Asthenosphere (properties)
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- Layer beneath the lithosphere
- Flows, or easily deforms (still solid) - Mesosphere (properties)
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The part of the mantle that extends from the core-mantle boundary to a depth of 660 km
- aka the "lower mantle" - Outer Core (properties)
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The convective flow of metallic iron that generates Earth's magnetic field
- Liquid layer - Inner Core (properties)
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The solid innermost layer of earth
- Radius of 1216 km - How do people believe the earth formed?
- After the "big bang", rotating debris collided and melted together
- 2 Types of Igneous Rocks
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Intrusive - rocks that form inside the Earth (plutonic)
Extrusive - Rocks that form on the outside (volcanic) - Textures of Igneous Rocks
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Vesicles - small, hollow pockets of air in the rock
Glassy - represents very small grains of quickly cooled magma
Pyroclastic - welded fragments of igneous rocks
Pegmatite - very large mineral grains - 3 general textures that represent cooling rates
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Aphanitic - fine grained, small crystals. Indicates that rock is extrusive (cooled quickly).
Porphyritic - crystals swimming in sea of fine grained crystals. (between aphanitic and phaneritic)
Phaneritic - large grained, bigger crystals. Indicateds that rock is intrusive (had more time to cool) - Composition of Igneous Rocks
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-Ultramafic/mafic rocks- Have large quantities of ferromagnesium minerals
-Felsic Rock- Have large number of nonferromagnesium minerals
-Intermediate- mixed proportions of minerals - 2 Types/Groups of minerals
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Ferromagnesium minerals - darker, denser minerals
-olivene, pyroxenes (augite), amphiboles (hornblende)
Non-ferromagnesium minerals - lighter, less dense minerals
-micas/clays, framework silicates (feldspar, quartz, orthoclase) - Definition of minerals
- Any naturally occuring, inorganic solid that possesses an orderly internal structure and definite chemical composition.
- Ionic Bond/Covalent Bond
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Ionic bond - one or more valence electrons are transferred from one to another
Covalent bond - sharing of electrons (usually gases) - How crystals form
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1. Evaporation of a liquid
2. From magmas
3. Previous minerals that make new ones - Silicates
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- Silicon-oxygen tetrahedron
- 4 oxygens surround 1 silicon atom
(SiO4) - Olivene Group
- Tetrahedra bond with metal cations
- Solid Substitution
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When 2 atoms of a similar size and charge can "substitute" into crystal at various proportions
(Fe,Mg)2SiO4 -
1. Tetrahedra
2. Single Chain
3. Double Chain
4. Sheet -
1. Si:O ratio is 1:4
2. Share one oxygen; 1:3 ratio
3. Share two oxygen; 1:2 ratio
4. Share three oxygen
-Tetrahedra are the basic building blocks for the crystal structure