Earth’s Interior & Plate Tectonics Vocab

1. Crust - Earth’s outer skin. Layer of solid rock that includes both dry land and the ocean floor. The main element is oxygen and silicon. Ranges between 5-40 km.

2. Oceanic crust- The crust under ocean is called 

3. Continental crust- (all the earth that is under continents) contains many types of rocks 

4. Mantle- has more magnesium and iron. Made of rock that is very hot, but solid. Divided into layers based on the physical characteristics of the layers. Nearly 3,000 km thick

5. Lithosphere- The Uppermost part is brittle like rock, Strong, hard, and ridged. 100 km thick

6. Asthenosphere - (plastic) Material is hotter and under increasing pressure causing the material to be less rigid than rock more like a ‘warm spoon’- can bend but would stub your toes if you kicked it

7. Plastic - another term for asthenosphere, upper mantle

8. Mesosphere- located beneath the asthenosphere, the mantle is more rigid. The Stiffness is due to increasingly high pressure. 

9. Transitional zone- a region which lines beneath the asthenosphere and also includes the lower mantle

10. Outer core- a liquid state 2,258km thick, has molten metal surrounding the inner core

11. Inner core- a solid ball with a radius of 1,222 km. A denser,  solid ball of metal. Extreme pressure squeezes the atoms of iron and nickel so that they can not physically spread over

12. Geographical north- True north, also called __ is the direction along the earth's surface (due to liquid core) 

13. Magnetic north- is the direction that your compass tells you is north. Rocks switch as well when the ___ switches

14. Alfred Wegener- A German meteorologist, polar researcher, and geophysicist who proposed the theory of continental drift. All the continents were once joined together in a single landmass and have since drifted apart 

15. Continental drift- The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present location. Wegener could not identify the cause of this, also Sea-floor spreading proved this

16. Pangea - Over tens of millions of years, it began to break apart and move toward their current locations

17. Mid-ocean ridges - These seams formed mountain ranges that form long chains up from the ocean floor, it extends into all of Earth’s oceans and form the longest mountain ranges on the planet

18. Seafloor spreading- the process by which molten material adds new oceanic crust to the ocean floor. In the 1950s geologists mapped the ocean floor using sonar. (bounces soundways off of the bottom of the ocean and what comes back, you can figure out what is on the ocean floor). This provided evidence in support of Wegener’s Hypothesis of Continental Drift. This also proved continental drift.

19. Deep-ocean trenches- the crust bends downward (Mariana Trench-crust being sucked down into the mantle where it is being heated and recycled)

20. Subduction-  the process by which part of the ocean floor sinks beneath a deep-ocean trench and back into the mantle again.

21. Tectonic plates- Pieces of lithosphere

22. Theory of plate tectonics- the Earth’s plates are in slow, constant motion, driven by convection currents in the mantle 

23. Fault- Breaks in the Earth’s crust where rocks have slipped past each other form along plate boundaries and are called

24. Divergent boundary-  Plates move apart [diverge] from each other

25. Rift Valley-  where pieces of Earth’s crust diverge on land causing a deep valley (that can fill with water and create a body of water like an ocean) 

26. Convergent boundary- 2 plates come together and collide

27. Density - __ of the plates determines which one comes out on top

28. Transform boundary- 2 plates slip past each other, moving in opposite directions.

29. Earthquake- Forces can later cause the 2 plates to unlock creating