Don Barrie, Geoscience Educator

Homework Assignment #1 GEOLOGY 100

Due several days before each exam (consult syllabus for due date).                                                                 Submit your typed assignment via WebCT by 11:59 PM Pacific Standard Time on the due date.

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Type out complete responses to each question.  Then, copy the questions and your responses, paste them into a Microsoft Word document, and submit your assignment via WebCT (see WebCT login instructions, above).  Save your Word document as follows:  Last Name_GEOL100_Hmk1 (e.g., Barrie_GEOL100_Hmk1). 

Guidelines for Student Collaboration on Homework Assignments:

While oral collaboration is encouraged (i.e, talking out homework answers with other students), you must complete this homework assignment on your own.  This means: do not share homework answers electronically with another student so that your work cannot be copied without your knowledge.

Your instructor may submit student homework assignments to www.turnitin.com for a plagiarism check.  Two or more students who turn in identical or nearly identical homework answers may receive a score of zero if evidence of electronic answer sharing is found.

Homework #1 Questions

1. Discuss four important characteristics of a scientific theory. 

2. What distinguishes science from other fields of knowledge? 

3. How do each of Earth's four compositional layers differ in terms of chemical composition and density? 

4. How do continental and oceanic crust differ in terms of density and composition? 

5. Distinguish between the lithosphere and asthenosphere. 

6. Describe the relative motion of two plates at various types of plate boundaries, including subduction zones, collision zones, transform boundaries, and divergent boundaries. 

7. Summarize several pieces of evidence that support the theory of plate tectonics. 

8. What processes are thought to drive plate motions? 

9. What defining characteristics do all minerals possess? 

10. Explain how the basic chemical building block of the silicate minerals—the silicate tetrahedron--is put together.  What is the chemical formula for this structure?  Why is the large negative of this structure important?  

11. List the silicate structure (e.g., isolated tetrahedra, single chains, double chains, sheets, 3-D framework, etc.) of each of these minerals: olivine, pyroxene, amphibole, biotite/muscovite, quartz, plagioclase feldspar (plag), potassium feldspar (K-spar). 

12. What is the difference between the ferromagnesian and non-ferromagnesian silicate minerals in terms of composition? 

13. Describe some important mineral properties used to identify common minerals in hand specimen.    

14. What is the order of crystallization (in terms of temperature) of various minerals (both discontinuous and continuous series) from a mafic magma as predicted by Bowen's Reaction Series? 

15. Explain the different ways that magmas can change composition. 

16. Distinguish between felsic, intermediate, and mafic magmas/igneous rocks in terms of silica content, potassium (K) and sodium (Na) content, calcium (Ca) content, and iron (Fe)/Magnesium (Mg) content.  No need to list actual percentates, just relative proportions (i.e., high, medium, or low).

17. What, besides temperature, affects melting and crystallization? 

18. What are the intrusive/extrusive equivalents for igneous rocks of felsic, intermediate, and mafic composition?  

19. Discuss the controls that effect the eruptive style of a volcano.

20. What is the basic textural difference between plutonic and volcanic rocks in terms of crystal size?  What does this difference tell us about cooling history?

21. Discuss the differences between the various volcano types, including shield volcanoes, cinder cones, and stratovolcanoes. 

22. Which type of volcano is most common at subduction zones?  Which type is most explosive?  Which types are associated with mafic magma?  Which type is associated with intermediate magma? 

23. Distinguish the two main types of weathering, and list several examples each of mechanical and chemical weathering processes. 

24. Explain how the susceptibility of common silicate minerals to chemical weathering relates to Bowen’s Reaction Series. 

25. Explain how mechanical and chemical weathering act together (i.e., reinforce each other) to disintegrate and decompose a rock mass. 

26. Which type of weathering predominates in arid environments? In humid environments?  Why?

Important Vocabulary (no need to define these terms; just be familiar with them)