Download STUDY GUIDE FOR TEST 3 (PLATE TECTONICS, GEOLOGIC TIME

STUDY GUIDE FOR TEST 3 (PLATE TECTONICS, GEOLOGIC TIME, FOSSILS,)
I. Plate Tectonics
1. Continental Drift
What are the observations that suggest that once-joined continents have moved apart?
What are the observations that suggest that continents have drifted together and “collided”? What suggests that they
have done it repeatedly?
What are the observations that suggest that continents have moved across latitudes?
2. Sea-floor spreading
If the oceanic crust off the North American continental shelf is basalt, but the nearest volcano is in the Mid-Atlantic Ridge,
how did the basalt get to the edge of North America?
What characteristics of the ridges/rifts suggest that they are places that plates are diverging from them?
As they diverge, how does new crust form to replace what is lost?
What is the composition of the crust formed there?
What idea relevant to sea-floor spreading was suggested by the “zebra-stripe map”? Explain briefly how the map
suggested that conclusion.
What are two ways the idea (in the question above) has been tested? What do the tests say about it?
3. Plate tectonics
What is a plate?
What evidence do we have that there is frequent movement at their edges?
What are the three main compositional layers of the Earth and what are the names of the boundaries between them?
What evidence do we have that the boundaries are there?
What evidence do we have for the densities of the layers?
What evidence do we have that the outer part of one is liquid (molten)? Which one is it?
What are the lithosphere and the asthenosphere? What are their characteristics?
How deep does the asthenosphere go?
What is the best hypothesis for the driving mechanism of plate movements?
What are some reasons I think the “slab pull” hypothesis is silly?
II. Principles of Geologic Time
For each of the basic principles we covered be able to recognize when it is being applied and what it says about past
events or ordering of events. For example, if I show you a stack of sediments, identify two different layers, and ask which
is older you should be able to answer and tell me that the principle of superposition is the key to answering. The basic
principles are:
Interpretation of single “Events”:
Uniformitarianism
Ordering of “Events”
Inclusions
Original Horizontality
Original Lateral Continuity
Superposition
Cross-cutting relationships
Ordering and time-constraint on “Events”
Fossil Succession
How did Hutton’s angular unconformity suggest the idea of “deep time” to him?
Outline the Eras (including the “Precambrian”) of the time scale and the ages of their boundaries. Do it in the correct
superpositional order.
How do you tell if a rock comes from one Era or the other? If I show you a picture of the relevant thing be able to identify
the Era.
III. Taxonomy
What was the original basis for the taxonomic classification we use?
Describe the idea of “clumping” of shapes that this hierarchy was meant to reflect.
Outline the levels of the taxonomic hierarchy including both singular and plural versions if the difference is not obvious.
This hierarchy maps onto geography. Describe what I mean by that.
The hierarchy also maps onto the Geologic Time Scale. Describe what I mean by that.