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Flashcards in CH7 Deck (16):
1

Expecting to learn

1) Plate tectonics
2)Plate boundaries
3) Evidence of Plate Tectonics
4) Paleomagnetism and Seafloor Spreading

2

Earth's Layers

1) Crust
-Continental
-Oceanic
2) Mantle-
-Upper Mantle (asthenosphere) -Lower mantle
3) Core
-Outer
-Inner

3

Continental drift

Alfred Wegner (1915)
Idea that all present day continents were at once part of a super continent (Pangea)

4

Plate tectonics

Earth's lithosphere is broken into several large rigid slabs called plates, that are moving apart along the MID-OCEAN RIDGES CONTINUALLY.

5

Earth's Major Lithospheric Plates

-Pacific
-North American
-South American
-African
-Eurasian
-Antarctic
-Indo-austeralian

6

3 types of plate boundaries

1) Convergent
2) Divergent
3)Tranform

7

Convergent

-Subduction Zones
-Volcanic Arcs
-Island Arcs

8

Divergent

-MOR (Mid Oceanic Ridge)
-Continental Rift Zone

9

Transform

-Slide past one another

10

Deformations associated with Plate boundaries

Convergent
-Folding, Faulting: Uplift
-Reverse faults

11

Deformations associated with Plate boundaries pt2

Divergent
-Thinning of the crust
– Subsidence
– NormalFaulting
– Tensionduetospreading
– Upwelling of Molten Material

12

Deformations associated with Plate boundaries pt3

Transform
– StrikeSlipFaultorTransform
Fault
– Slide past onea nother/ shearing
– No production or destruction of lithosphere

13

Evidence of Plate Tectonics

Continental Drift
– Wegener (1915)
-Fit of the continents
-Remarkable similarity between the coastlines on opposite sides of Atlantic ocean

• There have been 6 supercontinents in Earth’s history.

14

Evidence of plate tectonics

-Exact deposits of continental glaciers are found in near equatorial Africa, South America, and India.
• The fossil record supports and gives credence to the theories of continental drift and plate tectonics

15

Evidence of Plate tectonics

Paleomagnetism:Rocks that formed millions years ago contained “record” of the direction of the magnetic poles at the times of their formation

16

Hot Spots
- Evidence for direction and rate of plate motion

An area of unusual volcanic activity
• Not associated with plate boundaries
• Youngest at the hot spot
• Volcanic islands created by hot spots allow us to track the rate and direction of plate movement.