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Lab 423/623 Syllabus
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NDSU Geosciences Petrology 422/622 Spring 2006
Study Questions for Exam 3
Since the last exam, we have covered in lecture igneous systems across the range of tectonic environments: from mid-ocean ridges (Ch. 13) to ocean-intraplate environments (Ch. 14) to subduction related systems (Ch. 16 and 17). Granites are discussed in Ch. 18, and a brief discussion of continental rift volcanism (such as in East Africa) and of kimberlites in Ch. 19.
We have also covered introductory metamorphic petrology topics including:
- late stage magmatic alteration
- metamorphic facies and grades
- isograds
We have used class handouts and referred to the following portions of the Winter text:
Ch. 21, 22, table 23-1, Ch. 25.1 and 25.2, and the beginning of Ch. 28 (definition of pelite).
( Compatibility / chemographic diagrams such as AFM and ACF diagrams will not be covered in this exam, however, the facies concepts at the beginning of Ch. 25 will be.)
Below are some sample questions and topics.
Give a brief definition of the following terms:
- S-type vs. I-type granite
- ophiolite
- depleted mantle
- back-arc basin
- pelite
Discuss (perhaps with the aid of supporting diagrams):
- Explain the origins of any similarities or differences between N-type MORB, P-type MORB, and oceanic island tholeiitic lavas.
- What are potential sources for magmas in island arc settings? Which do you think are the most important, and why?
- Name a slow spreading mid ocean ridge, and a fast spreading one. What are differences between the two?
- Draw a cross section of typical ocean crust.
- How does the albite-SiO2-K-Feldspar phase diagram change with pressure, and how does this influence our understanding of granite formation?
- Describe the physical form, mineralogy and genesis of kimberlite.
- What are the five types of metamorphism that Winter recognizes, and briefly describe each.
- What minerals would you expect to find in a metamorphosed mafic rock at high P and low T? (see Table 25-1 and handouts)
As always, think up similar questions.
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