Reference no: EM133773189

Questions:

1. What about rocks that are not aggregates of minerals? Name and describe two distinctly different mineral examples.

2. There are two fundamental kinds of sedimentary rocks. Name them and name examples of each.

3. Subvolcanic rocks, also known as a hypabyssal rocks, are sometimes described as intermediate between the two fundamental kinds of igneous rocks. Explain this. Explain the logic.

4. The first two photos of the text show basalts that contain large olivine crystals. Olivine is common in basalts but not very common in most other kinds of rocks. Why?

5. Many olivine basalts contain glass in lieu of minerals. What is the difference between volcanic glass and minerals?

6. While igneous, metamorphic, and sedimentary are the fundamental kinds of rocks, rocks can be divided in other ways. For example, some petrologists make a big deal out of the distinction between crystalline and clastic rocks. What does this mean? What are the differences between the two types?

7. Igneous rocks may be crystalline or clastic. Name examples of each and describe how they form and what they are made of.

8. What kinds of igneous rocks (name them) are typically found at: a. mid ocean ridges; b. subduction zones; c. island arcs; d. oceanic hot spots

9. Contrast and compare the following terms: plutonic rock, intrusive rock, extrusive rock, volcanic rock.

10. Volcanoes may produce lavas during an eruption. What other kinds of materials will they produce? Why different things in different situations? What are the controlling factors?

11. Why do magmas rise in the Earth?

12. Figure 1.2 in the text shows a rock that appears to have crystallized in two stages. Why do I say this?

13. What are the key differences between petrographic microscopes and other kinds of microscopes?

14. Petrologists are often concerned with rock composition -- with a rock's geochemistry. What sort of instruments do they use to determine rock composition. Name two and briefly describe how they work.

15. The most common sedimentary minerals are quartz and clay. Why?

16. Some clastic sedimentary rocks contain well-rounded grains and some do not. Why?

17. Some sediment eventually becomes lithified to become a conglomerate. In what sorts of environments might that sediment accumulate?

18. Limestones may be either clastic or chemical sedimentary rocks. (And probably can also be somewhere between the two.) Describe and explain how clastic limestones may form, and how chemical limestones may form.

19. Sandstones rarely contain fossils. Why?

20. Different kinds of metamorphic rocks contain different minerals. Why? There are at least two good answers.