Metamorphism Web Exercise for Geology 1

Go to the book's Web Site, student edition, as usual, take the Chapter 7 multiple choice quiz on the website.
Note your quiz scores and date taken on a paper. Take the multiple choice portion of the end of chapter questions. check the answers at the web site. Note your score and date taken on the same paper. This is item (or page) 8Ain your portfolio.

 

INSTRUCTIONS:
Answer all of the questions. Keep all on one page. This is page 8B of your portfolio.

Go to University of British Columbia's site: http://www.science.ubc.ca/~geol202/meta/metamorphic.html
The overview is worth reading for a review of material covered in class and to learn more about metamorphism.
Go to metamorphic rock names. Click on "bulk composition."
1. What two rock names on the list are covered in this class and what are their compositions?
Go back and click on "grain size and fabric development." Note that phyllosilicates are sheet silicates (clays, micas). Read through the descriptions of rock names we covered as a review.
2. What is the distinction between orthogneiss and paragneiss?
Go forward once then again to metamorphic textures.
Click on "metamorphic microtextures." (This takes you to U. of N. Carolina) or you can go there directly with:
http://www.geolab.unc.edu/Petunia/IgMetAtlas/meta-micro/metamicro.html
. Click on foliation.
3. which two minerals are shown in this photomicrograph? Which mineral is showing the pronounced parallelism that makes the rock foliated?
Go back and click on "porphyroblastic texture." A porphyroblast is a larger crystal surrounded by finer-grained rock. The porphyroblast in this case is garnet. It appears black in crossed-polaroid light. To see it in plane-polarized light, click on the circle with the grey horizontal lines. To go back to crossed-polarized light, click on the two overlapping circles.
4. The brightly colored mineral under cross-polarized light (clear in plane-polarized light) is: (Hints: note the cleavage cracks; it is one of the same minerals of question 3 above.)
Go back to the list of microtextures and click on "slate." Note the very fine-grained nature of this rock (relative to the scale)
5. What is the direction of orientation of the foliation? (left-right or top-bottom)
6. Go back to the list of microtextures and click on "marble" and then "quartzite." Note the mosaic of interlocking grains and lack of foliation. What physical property can you observe that allows you to distinguish quartz in one from calcite in the other?