Envisci Exam 9/28 6

Front 1

Plate tectonics

Back 1

A theory of global tectonics stating that the lithosphere is segmented into several plates that move about relative to one another by floating on and gliding over the plastic asthenosphere. Tectonic activity occur mainly at the plate boundaries

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Pangea

Back 2

the supercontinent that existed when all Earth's continents were joined together, about 300 to 200 million years ago.
(First identified by Alfred Wegener)

Front 3

Gondwanaland

Back 3

The southern part of Pangea

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Continental Drift

Back 4

the theory proposed by Alfred Wegener that Earth's continents were once joined together and later split and drifted apart (this theory was replaced by the more complete plate tectonics theory)

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Asthenosphere

Back 5

The portion of the upper mantle just beneath the lithosphere extending from a depth of about 100 kilometers below the surface of Earth and consisting of weak, plastic rock where magma may form

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Normal magnetic polarity

Back 6

A magnetic orientation (in rocks)that is the same as that of Earth's current magnetic field

Front 7

Reversed magnetic polarity

Back 7

Magnetic orientations in rock that are opposite to the current orientation of Earth's magnetic field

Front 8

Magnetic reversal

Back 8

A change in Earth's magnetic field in which the north magnetic pole becomes the south pole and vice versa; occurs every 500,000 years

Front 9

Sea-floor spreading

Back 9

The hypothesis that segments of oceanic crust are separating at the Mid-Oceanic Ridge

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Plate boundary

Back 10

A fracture or boundary that separates two tectonic plates

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Divergent boundary

Back 11

A boundary where two tectonic plates move apart from each other (so new lithosphere is continuously forming)

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Convergent boundary

Back 12

A plate boundary where two tectonic plates move toward each other or collide head on

Front 13

Transform boundary

Back 13

A plate boundary where two tectonic plates slide past each other

Front 14

Continental drift

Back 14

The process by which a continent is pulled apart at a divergent plate boundary

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Subduction

Back 15

The process in which two lithospheric plates of different densities converge and the denser one sinks into the mantle beneath the other

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Clastic rocks (sedimentary)

Back 16

formed from small pieces of other rocks

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Chemical rocks (sedimentary)

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formed by the precipitation of small rocks

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Biogenic-- "organic" and "bioclastic"
(sedimentary)

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living organisms have played some role in forming these rocks

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What are the 2 styles of Metamorphism?

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REGIONAL and CONTACT

Regional: result of pressure
Contact: when the metamorphism is a result of contact with hot water or hot magma

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Rock forming processes:
IGNEOUS

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Source of material: melting of rocks in hot, deep crust and upper mantle

Rock-forming process: crystallization (solidification of magma)

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Rock forming processes:
SEDIMENTARY

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Source of material: weathering and erosion at the surface

Rock-forming process: deposition, burial and lithification

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Rock forming processes:
METAMORPHIC

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Source of material: rocks under high temperatures and pressures in deep crust and upper mantle

Rock-forming process: recrystallization in solid state of new minerals

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Lieutenant Matthew Maury

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"Pathfinder of the sea"
First proposed the theory of an underwater mountain range (today known as the Mid-Oceanic Ridge system)

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From what does the Earth's magnetic field the result?

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The movement of liquid iron in the outer core

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Conduction

Back 25

Heat moves through a solid without any movement of material

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Convection

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hot, less-dense materials rise upward and are replaced by cold, downward-flowing materials

CAUSES divergent margins to shift on the ocean floor