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24 Cards in this Set
- Front
- Back
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Wegener's evidence |
1. Jig-saw puzzle fit of continents 2. Similar sequences of rocks on different continents 3. Distribution of glacial striations 4. Distribution of fossils |
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Why Wegener's theory wasn't accepted |
-No realistic of HOW the continents moved -Continents were supposed to "plow through" ocean basins |
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Ocean topography |
Map showing: Mid ocean ridge-chain of submerged mountains Abyssal Plain-Deep, flat portion of success Trenches-Narrow steep-sided depressions |
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Magnetic studies |
Positive=North Pole Negative=South Pole
When magnetite crystals cool below the CURIE POINT, Earth's magnetic field records whether it's "normal" or reversed" |
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Age of ocean floor |
Younger than 200 million years |
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Sea Floor Spreading pt. 1 |
Ocean ridges are zones of weakness |
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Sea Floor Spreading pt. 2 |
Magma, rising from the upper mantle, erupts at mid-ocean ridges and new crust is created
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Sea Floor Spreading pt. 3 |
As new seafloor moves away from the ridge, it cools and becomes denser |
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Plate Tectonics pt. 1 |
The processes associated with the creation, movement and destruction of lithospheric plates |
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Plate Tectonics pt. 2 |
Produce landforms such as ocean basins, continents, and mountains |
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Plates |
Rigid slabs of lithoshere |
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Plate boundaries |
Plates slide past, override, tear, smash into each other |
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Types of plate boundaries |
Convergent Divergent Transform |
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Divergent |
Pulling apart Tension/extension Not as powerful |
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Convergent |
Coming together Compression More powerful
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Transform |
Plates slide past each other
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Hot spots |
Caused by plumes of hot partly molten material that rise from deep in the mantle |
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Divergent Boundaries |
Hot ductile mantle rocks rise to the surface High heat flow Continental rifting leads to new ocean basins |
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Convergent Boundaries |
High Seismic activity Reverse faults-compressive stress Low heat flow |
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Types of convergent boundaries |
Ocean-Ocean Ocean-Continent Continent-Continent |
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Ocean-Ocean |
Older, denser ocean lithosphere subducts; younger less dense ocean lithosphere is over-riding plate
Oceanic lithosphere is destroyed Develop deep ocean trench Develop Island arc of volcanic arc |
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Ocean-Continent |
Ocean lithosphere subducts; continental lithosphere is over-riding plate
Similar to Ocean-Ocean |
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Continent-Continent |
Develop continental suture
Neither plate subducts, both too buoyant---push up big mountain range
Seismic activity but no valcanism
Area of much metamorphism |
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Transform Boundaries |
High level of seismic activity low heat flow no destruction to lithosphere |
