Department
of Earth Science |
Northeastern
Illinois University
INTRODUCTION
TO EARTH SCIENCE
ESCI
121
Spring
2007
Daily Objectives
#9 (February
14, 2007)
Dr. Sanders
Homework
#3 (see the homework
page) is
due today!
By the end
of
today’s class, you should be able to do the
following:
Review: Sedimentary Rocks
* List the two main groups of sedimentary rocks.
* For each group, explain how rocks in that group form, list a few
names of rocks that fall into that group, tell what minerals make up
that rock (for the chemical sedimentary rocks), tell what the grain
size of sediments is (for the detrital sedimentary rocks), and tell how
you might recognize each of the rocks when you see them again.
Igneous Rocks
* Sketch a "melting curve" on a graph with axes showing temperature and
pressure. Show on which sides of the curve liquids and solids
would exist.
* Use the melting curve you sketched to illustrate the three processes
that lead to melting of rock material:
- thermal melting (increasing heat)
- decompression melting (reducing
pressure)
- shifting the position of the melting
curve by introducing volatiles (i.e., water)
* Describe the three general settings in which volcanoes are found in
the world, and for each, use the melting curve to explain how/why magma
forms in that setting:
- divergent plate boundaries
- subduction zones
- hot spots
* Explain the relationship between cooling rate and crystal size in an
igneous rock.
* Using the hand samples of igneous rocks in a rock box, tell
which of them cooled relatively slowly, quickly, and instantaneously.
* Explain the
difference between granitic (felsic) composition and basaltic (mafic)
composition, and how to recognize each type in a hand sample.
* Describe the unique characteristics, including crystal size and
composition, of each of the following igneous rocks:
-
granite -
gabbro - rhyolite
- basalt -
pumice - obsidian
© 2007 Laura L. Sanders. Last updated
February 14, 2007.