Stressing Out the Rocks
This paper is being submitted, by Cynthia Phillips by class, G245/GLY1000 Section 01 Introduction to Geology
Title: Week 5 Written Assignment
Course: G245 - Introduction to Geology
Instructor: Michelle Sutherland
1) Define each of the following stressors:
a. Compression-When rocks are pushed together, the largest stress is horizontal and the lowest stress is vertical the rocks will contract, crumpling, and causing them to thicken vertically and shorten laterally. (Chernicoff.S & Whitney, D 2007)
b. Tension-When rocks are pulled apart (ex-tension), such as at diverging plate margins, the largest stress is vertical and the lowest is horizontal; this type of stress is known as tension (Chernicoff.S & Whitney, D 2007) the tension does cause stress and stretches the rock, so that it will thin out vertically and lengthen, this will create a tear in the rock c. Shearing- “When rocks are forced past one another in parallel but opposite directions, such as at trans-form plate margins, the stress is known as shearing.” (Chernicoff.S & Whitney, D 2007) what it will do it puts stress and typically slices the rock like a tomato, into horizontal blocks, displacing the structures.
2) Define each of the following types of strain (which are caused by stress):
a. Elastic- “When the stress is minor, a rock may return to its original shape and volume after the stress is removed much as a stretched rubber band re-gains its original shape after use,” (Chernicoff.S & Whitney, D 2007) when a rock that is deformed elastically will not be permanently deformed.
b. Plastic, this is where the rock being underground several kilometers under the Earth’s surface, has an irreversible change in the shape that will occur without the rock breaking. “During plastic deformation, atoms move about and adjust to an applied stress by...
References: Chernicoff S &Whitney D (2007) Geology, an Introduction to Physical Geology (4th ED) Pearson Hall ISBN 978125857075
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