Plate Tectonic Test Review Answers!

Fill in the Blank, Plate Tectonics: The Theory of Continental Drift was proposed by Alfred Wegner in 1912. The theory states that all the continents were once one supercontinent named Pangaea and have since drifted apart to their current locations. The evidence that supports Continental Drift is: similar fossil evidence from different continents, the landforms line up, and the coastlines of the current continents fit together like a puzzle. The Continental Drift Theory has since changed into the Theory of Plate Tectonics. This theory states that the earth’s crust is broken into large moving pieces called plates to which the continents are attached. Along with the evidence that was used to support Continental Drift, new evidence such as sea floor spreading, earthquakes and volcanoes, and actual recorded movement all help support Plate Tectonics.

The crust is broken into 16 plates: These plates shift and move in all directions. Where they meet one another is called a plate boundary. There are three types: A divergent boundary is where the two plates move away from one another. Here we find rift valleys and ridges. New crust is formed at these types of boundaries. An example of this type of boundary is the Mid Ocean Ridge. A convergent boundary is where the two plates move toward one another. If subduction occurs, then one plate is forced underneath the other and ocean trenches and coastal mountain ranges with volcanoes are formed along the boundary. If collision occurs then both plates collide and push upward creating Tall Mountains with mild earthquakes. An example of this type of convergent boundary is found in the Himalayan Mountains of India. The third type of boundary is called a transform boundary. At this boundary the plates move past one another in different directions. This movement creates visible faults and lots of earthquakes. Prime example is the San Andreas Fault in California. During sea-floor spreading, new crust forms when molten material from the mantle will rise up and fill in to form New Ocean Crust. The opposite edges of the boundary then become subducted.

What is the difference between a constructive and a destructive force that shapes the Earth’s surface? Constructive forces = build Destructive forces = break down / destroy What happens to the temperature and pressure as you go deeper into the Earth? Both increase What indirect method can be used to map the bottom of the deep ocean floor? ______sonar ______

Describe what each layer is made of: Crust: hard rock and minerals Inner Core: solid metal (iron and nickel) Outer Core: melted (molten) metal Mantle : magma, hot rock

Name the three basic types of rocks. sedimentary, metamorphic, igneous 2. From what material are igneous rocks formed? magma 3. Explain the difference between intrusive and extrusive igneous rocks. Extrusive rock hardens above the surface of the Earth. Intrusive rock hardens in the ground and has more crystal because it takes longer to cool. 4. In the rock cycle the processes of __heat_ and ___pressure___ produce metamorphic rock. Sediments for sedimentary rock are produced by the processes of ___erosion___ and _____weathering__ from the forces of the elements above the earth’s surface. Igneous rocks form when molten material __melts__ into magma and __hardens (crystallizes)__ as it cools.

5. List and describe the 3 steps of lithification: deposition compaction cementation 7. Fossils are found in ___sedimentary______rock.

____Metamorphic rock__ ___Igenous rock______ __Sedimentary rock__ Igneous rock Metamorphic rock Sedimentary rock ____Metamorphic rock__ sediments magma ___Igenous rock______ __Sedimentary rock__ Deposition, compaction, and cementation occurs Magma crystallizes, or hardens to form this rock Erosion & weathering occur to form sediments Rock melts to form magma Heat and pressure is applied Heat and pressure