Flashcards in Exam 2.1 Deck (21):
Who created the theory of continental drift?
What was Wegener's evidence of Pangaea?
- continents fit
- fossil distribution
- ancient mountain belts
- matching rock units
- patterns of glaciation
Why was the theory of Pangaea rejected?
The tectonic plates were thought to not have enough force of motion to move continents
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
What happens to the crust at spreading centers?
New sea floor and oceanic lithosphere are formed above rising magma
What happens to the crust at subduction zones?
Areas of descending older oceanic lithosphere
What is Wilson's theory of plate tectonics?
- continental drift and sea floor spreading unified
- lithosphere fragmented into 7 major plates
Describe earths inner core
- spins and creates magnetosphere
- made of iron and nickel
Describe earths outer core
- made of liquid molten rock
- S waves cant pass through
What is the mantle?
- solid bulk of earths interior
- inbetween core and crust
- composed of basaltic rock
What are the 3 parts of the mantle?
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
What is basalt?
What is granite?
Rock formed by the crystallization of magma below earths surface
What is isostasy?
- equilibrium of earths crust
- if something is removed, something rises ect
Where does tectonic plate activity occur?
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
What geological processes are at work at transform boundaries?
- plates slide against
- sea floor conserved
What geologic processes are at work at continent/continent convergent boundaries?
- mountain building
- mountain ranges
What geologic processes are at an ocean/continent convergent boundary and subduction zone?
Old sea floor is destroyed by subduction, ocean trenches created