Study Guide

Definitions

Short Answer Questions

1. In examining two rock specimens, you discover that they both have the same mineral composition yet one has an aphanitic texture while the other has a phaneritic texture. Describe how these two rock specimens formed. What is the evidence? How are the two rocks related?
2. You find a rock composed of sand and pebbles cemented together. You determine that it has a clastic texture and that much of the coarser material is composed of feldspar. What kind of rock is it? Be specific! How was it formed? What does it tell you about the environment where the rock formed?
3. How is the structure of the mineral quartz similar to feldspar? How are they different?
4. How does the structure of mica affect its physical characteristics?
5. What are the characteristic properties of the mineral galena that allow its identification?
6. How does a laccolith differ from a sill?
7. Under what environmental conditions does the mineral gypsum form?
8. Silicate minerals are composed of silica tetrahedra linked in various ways. How are the tetrathedra linked in the following minerals: quartz, feldspar, muscovite, olivine, pyroxene, and amphibole?
9. How does the chemical composition of oceanic crust differ from continental crust?
10. How can you differentiate between a limestone and a marble?
11. How do cross-beds form? Include a diagram in your answer
12. List the different types of plate boundaries and describe the nature of the motion at each one.
13. Why do some areas on the surface of the earth fail to receive seismic waves from a large earthquake?
14. How does sand deposits formed from wind currents differ from sand deposits formed from river currents?
15. What does an angular unconformity in the geologic record indicate about the geologic history of the region?

Essay Questions

1. Explain how the minerals kyanite, andalusite, and sillimanite can be used to determine the conditions under which metamorphism took place.
2. Use Bowens reaction series to explain the process of magmatic differentiation. How can a basalt magma evolve into a granitic magma?
3. How are sedimentary rocks classified? What does the classification tell you about the environment of deposition?
4. How are igneous rocks classified? What does the classification system tell you about how each type of rock forms?
5. Explain how magmas are genearted at convergent plate boundaries and contrast with the mechanism of magma generaltion at divergent boundaries.
6. In examing an igneous rock you find a zoned plagioclase feldspar (shown below). How does the composition of the feldspar change from the center outward? What does this indicate about what is happening in the magma chamber.
   

Photo Questions

	This is a photo of the surface of an outcrop of basalt. What are the prominant features visible in this photo?
	How was this rock formed? What is your evidence?
	Carefully classify this rock and explain in as much detail as you can the conditions under which it formed.
	Write a description as to how this sediment was deposited. Use the features that you observe in this photo to support your hypotheses.
	This is a photo of some features observed in shallow water near the shoreline of a lake (note the reflection off the waters surface on the left side of the photo). What are these features and how did they form?
	This is a thin section of a rock. What is its texture?
	This is a photograph of a mountain in Wyoming. What is the prominant black feature that runs vertically through the photograph?
	Under what plate tectonic conditions did this mountain form? How did it form and of what kind of rock is it composed?
	What kind of rocks are exposed in this area? What caused the vertical ridge and gully pattern? What specific observations support your hypothesis.
	This is a thin section of a rock. Use your observations to develope an hypothesis to explain how this rock formed. What is your evidence?
	What kind of rock is this? How did it form? What is your evidence?
	This is a close-up view of the polished surface of a rock. What kind of rock is it? What is your evidence?
	Write a brief geologic history for the area shown in this slide.
	Create a simple stratigraphic column (column of letters) showing the relative age of the rocks from oldest at the bottom to youngest at the top AND write a brief geologic history of this area.