Term
| When and how was the Theory of Plate Tectonics developed? |
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Definition
Developed in the 1960s
Advancing mapping and surveying technology
Sea floor mapping discovered the Mid-Atlantic Ridge. |
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Term
| What is the theory of Plate Tectonics? |
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Definition
States that the Earth is composed of large tectonic plates that move and interact.
-Oceanic plates
-Continental plates
-Shapes the topography of the Earth’s surface |
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Term
| Why is the Theory of Plate Tectonics important? |
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Definition
| Elegantly explains many geologic phenomena. For example, the locations and causes of earthquakes, volcanism, mountain-building, rift zones, and mid-ocean ridges, etc. |
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Term
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Definition
Thinner than Continental Crust (7-10km)
More dense than Continental Crust
Mafic composition |
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Term
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Definition
Thicker than oceanic crust (25-70km)
Less dense than oceanic crust
Felsic composition |
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Term
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Definition
Lower amounts of silica (SiO2) and higher amouts of Fe, Mg and Ca
ex: Basalt |
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Term
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Definition
higher amounts of silica (SiO2), Al, Na and K
ex: granite/diorite (granodiorite) |
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Term
| Evidence Supporting Plate Tectonics |
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Definition
1. Matching coastlines (Pangea, "puzzle piece" observation)
2. Correlating rock units and fossils in different continents that are currently far away from each other
3. The locations of earthquakes, volcanoes, geothermal activity, etc
4. Magnetic data gathered from rocks around mid-ocean rides |
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Term
| How do tectonic plates move? |
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Definition
- Mantle convection initiates the formation/alteration of tectonic environments and strongly controls plate direction
- Other contributing processes are slab pull and ridge push which contribute strongly to the rate of plate movement (especially slab pull) |
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Term
| How do we measure plate motion? |
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Definition
1. GPS
2. Piercing points - two halves of the same structure that have been moved apart by tectonic forces (determined by knowing when the two halves were together and seeing how far they have drifted apart through time.) |
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Term
| What are the three types of tectonic settings? |
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Definition
1. Convergent Margins
2. Divergent Margins
3. Transform Margins |
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Term
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Definition
2 plates run into each other
*Subduction -> Volcanism*
*Mountain Building* |
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Term
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Definition
2 plates moving away from each other
*Creation of new oceanic crust* |
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Term
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Definition
2 plates moving past eachother via side-by-side contact
*Pacific and North American Plate (San Andreas Fault)* |
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Term
| How are mountains formed? |
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Definition
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