In-class physical geology exercise: inferring deformation conditions for rock structures.

Observe the rock type and the structures in the specimen given your group. Use what you have learned in lecture, in your reading and in the lab to answer the following questions and fill out the sheet below.

Identify the rock type. ____________________________

Identify, the best you can, the structures in these rocks.

 

 

Are the structures present mostly brittle, mostly ductile, or a mixture?

Identify any planar or linear elements present.

 

At what depth in the crust do you think the rock was deformed? You can think of three possibilities: in the seismogenic portion, in the brittle ductile transition, in the shallow metamorphic realm, in the deep metamorphic realm.

 

Is this consistent with the metamorphic character of the rock?

 

If appropriate identify in what direction the rock was flattened or stretched.

Note any other interesting structural aspects of the specimen.

 

List participants below:

 

 

Chose a spokesperson to give a quick summary of your answers to the questions above.