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Flashcards in Exam 2.1 Deck (21):
1

Who created the theory of continental drift?

Alfred Wegener

2

What was Wegener's evidence of Pangaea?

- continents fit
- fossil distribution
- ancient mountain belts
- matching rock units
- patterns of glaciation

3

Why was the theory of Pangaea rejected?

The tectonic plates were thought to not have enough force of motion to move continents

4

What was Harry Hess's seafloor spreading hypothesis?

- sea floor created along ocean ridges, and koves away from ridges
- eventually subducted into mantle at ocean trenches
- new sea floor created, old destroyed

5

What happens to the crust at spreading centers?

New sea floor and oceanic lithosphere are formed above rising magma

6

What happens to the crust at subduction zones?

Areas of descending older oceanic lithosphere

7

What is Wilson's theory of plate tectonics?

- continental drift and sea floor spreading unified
- lithosphere fragmented into 7 major plates

8

Describe earths inner core

- spins and creates magnetosphere
- made of iron and nickel

9

Describe earths outer core

- made of liquid molten rock
- S waves cant pass through

10

What is the mantle?

- solid bulk of earths interior
- inbetween core and crust
- composed of basaltic rock

11

What are the 3 parts of the mantle?

- lithosphere
- athenosphere
- mesosphere

12

What is the difference between the lithosphere and athenosphere?

Lithosphere: consists of top mantle, crust, and carry the tectonic plates
Athenosphere: semi plastic, liquid layer
- sits under lithosphere
- transfers heat from core

13

What is basalt?

Volcanic rock

14

What is granite?

Rock formed by the crystallization of magma below earths surface

15

What is isostasy?

- equilibrium of earths crust
- if something is removed, something rises ect

16

Where does tectonic plate activity occur?

The lithosphere

17

What geologic features can divergent plates cause?

Ocean/Ocean - new sea floor created, causes mid ocean ridges, earthquakes, volcanoes

Continent/Continent - continent breaks apart, new ocean basins form, causes continental rifts, shallow seas, earthquakes, and volcanoes

18

What geological processes are at work at transform boundaries?

- plates slide against
- sea floor conserved

19

What geologic processes are at work at continent/continent convergent boundaries?

- mountain building
- mountain ranges

20

What geologic processes are at an ocean/continent convergent boundary and subduction zone?

Old sea floor is destroyed by subduction, ocean trenches created

21

What geologic processes are at work on an ocean/ocean convergent boundary?

Old sea floor destroyed by subduction, ocean trench created