EAPS 111 Exam 1 Purdue Questions and Answers with
complete solution
1. A fundamental premise of plate tectonics is that the Earth's surface is made
of distinct plates. What are the kinds of evidence/observations led
geoscientists to conclude this?
-The presence of fossil evidence as well as physical boundaries for continents and
chains of seismic activity, they can fit together and plants, sediments
2. Where these plates interact (at their active boundaries) is where a significant
fraction of the tectonic activity occurs. There are 3 basic active plate
boundaries types. What are they and how would you describe the large-scale
motions at each?
-Divergent- move apart
-Convergent- come together
-Transform- slide past each other
3. What are the characteristics of the three types of plate boundaries in terms
of plate motions, association of earthquakes and volcanoes, and presence or
absence of mountains (or other distinctive features)?
-Divergent- results in mid ocean ridges, lava rises out of faults created by plates
moving apart
-Convergent- subduction zones, causes higher plate to rise, volcanic activity from
falling plate common. Earthquakes can result from sudden slips of the footwall.
-Transform-plates move past each other causing earthquakes, mountains or valleys
not common.
4. What does the orientation of volcanic island chains indicate?
-presences of a convergent plate boundary, which way the plate is moving
5. Can you distinguish the different plate margins from map and elevation
data?
Top is above sea, bath, below sea.
6. What is convection, how does it work (think of the analogies we used in
class)?
-the heating and cooling of rock creating a cycling motion. Gravity pulls the upper
cooler rock down (because it's denser) and then heats it, causing it to rise (less
dense), creating a cycling motion
7. Why is convection relevant to plate tectonics?
-convection drives the movement of plate tectonics, causing the rock to move either
apart, together, or past each other
8. Be able to identify and explain seafloor features and other tectonic elements
on continents and relate these to convection and plate tectonics.
-seafloor features are effected by plate tectonics as well, for example divergent plate
boundaries result in mid ocean ridges
9. Understand the details of subduction and sea floor spreading, in terms of
large-scale physical processes (i.e., convection).
-Seafloor spreading is the result in a counter clock wise and clockwise convection
zone
10. How (and why) do continents grow continuously larger through time while
ocean basins grow and shrink through the actions of plate tectonics?
complete solution
1. A fundamental premise of plate tectonics is that the Earth's surface is made
of distinct plates. What are the kinds of evidence/observations led
geoscientists to conclude this?
-The presence of fossil evidence as well as physical boundaries for continents and
chains of seismic activity, they can fit together and plants, sediments
2. Where these plates interact (at their active boundaries) is where a significant
fraction of the tectonic activity occurs. There are 3 basic active plate
boundaries types. What are they and how would you describe the large-scale
motions at each?
-Divergent- move apart
-Convergent- come together
-Transform- slide past each other
3. What are the characteristics of the three types of plate boundaries in terms
of plate motions, association of earthquakes and volcanoes, and presence or
absence of mountains (or other distinctive features)?
-Divergent- results in mid ocean ridges, lava rises out of faults created by plates
moving apart
-Convergent- subduction zones, causes higher plate to rise, volcanic activity from
falling plate common. Earthquakes can result from sudden slips of the footwall.
-Transform-plates move past each other causing earthquakes, mountains or valleys
not common.
4. What does the orientation of volcanic island chains indicate?
-presences of a convergent plate boundary, which way the plate is moving
5. Can you distinguish the different plate margins from map and elevation
data?
Top is above sea, bath, below sea.
6. What is convection, how does it work (think of the analogies we used in
class)?
-the heating and cooling of rock creating a cycling motion. Gravity pulls the upper
cooler rock down (because it's denser) and then heats it, causing it to rise (less
dense), creating a cycling motion
7. Why is convection relevant to plate tectonics?
-convection drives the movement of plate tectonics, causing the rock to move either
apart, together, or past each other
8. Be able to identify and explain seafloor features and other tectonic elements
on continents and relate these to convection and plate tectonics.
-seafloor features are effected by plate tectonics as well, for example divergent plate
boundaries result in mid ocean ridges
9. Understand the details of subduction and sea floor spreading, in terms of
large-scale physical processes (i.e., convection).
-Seafloor spreading is the result in a counter clock wise and clockwise convection
zone
10. How (and why) do continents grow continuously larger through time while
ocean basins grow and shrink through the actions of plate tectonics?
