Homework Writing Help on GEOL

GEOL

This homework looks the structural deformation of three different locations in Colorado and interprets the type of stresses necessary to create such features. This will be referring to ideas in Chapter 8.

Part I:  Structural interpretations of Loveland, Colorado.

Answer the following questions regarding the observations from the figures and photographs in the images PDF for Loveland Colorado

2 What main type of fold is observed at location X, (Devil’s backbone and to the east) ?Anticline fold
3. What was the type of differential stress that most likely resulted in the fold that forms Devil’s Backbone?Shear stress
4. Which of the main types of faults is observed at location Y?Syncline fold
5.  What was the type of differential stress that most likely resulted in fault observed at location Y?Shear stress
6. What was the direction of the differential stress? (E.g. east-west direction? North –south?)East-west direction

7. Write one to two sentences that summarize your interpretations from above of how the rocks in the Loveland, CO area were deformed. (3 pts.)  Be sure to include the following:

Through faulting and folding

  • What are the deformation features that are observed? 

   Faulting and folding

  • What was the most likely differential stress?

Shear stress

What was the direction of the differential stress?

The stress was by concentric folding upwards to a limiting curvature. Afterwards, additional displacements took place by faulting across the sharper limb of the anticline

8. The gneiss rock pictured in figure 3 that is west of Loveland was formed during a much older deformation event than what is depicted in the cross section above.

What was the type of differential stress that occurred in this much older event and, how deep was the rock when it was deformed? (2 pts.)

The rock was deep beneath the earth’s surface.

Part II:  Structural interpretations of Boulder, Colorado. (11 pts.)

Answer the following questions regarding the observations from the figures and photographs in the images PDF for Boulder, Colorado

9. Which named sedimentary layer (e.g Fountain Formation, Benton Formation, etc..) is present on both sides of the Boulder fault?Benton Formation
10. What main type of fault is present at location M on figure 4, the cross section of Boulder, CO?Low angle fault or thrust fault.  
11.  What was the type of differential stress that most likely resulted in the fault observed at location M?Shear stress
12. What types of deformational features is present at Six Mile, just north of Boulder (e.g. fault/fold/joint/etc.), figure 5 and 6?Fault and fold
13. What was the type of differential stress that most likely resulted in the features seen at Six Mile?Compressional stresses
14. What was the direction of the differential stress that created both of these features? (e.g. east-west direction? North –south?)South-north direction

15. Write one to two sentences that summarize your interpretations from above of how the rocks in the Boulder, CO area were deformed. (3 pts)  Be sure to include the following:

Rocks in the boulder were deformed through the forces of mounting building.

What are the deformation features that are observed? 

Plastic and brittle deformation features.

  • What was the most likely differential stress?

Shear stress

  • What was the direction of the differential stress?

North-south direction

16. Based on your observations of deformation in Loveland CO and Boulder, CO, is it possible that these deformation events are related to one another? Why or why not? ( 2 pts)

Based on the observation, these deformation events are not related to one another since the estimates of the Laramide strain at the north of the plateau should not be connected with the older displacements since they have resulted from a complex combination of the rotation of Laramide plateau and shortening that is directed eastwards with the Sevier thrust and fold salient formation.

Part III:  Structural interpretations of features around Trinidad, Colorado. (8 pts.)

Answer the following questions regarding the observations from the figures and photographs in the images PDF for Boulder, Colorado

17. What type of fault is present on figure 7?Type of fault present in figure 7 is thrust fault
18.  What was the type of differential stress that most likely resulted in this fault?Compressional stress which results in a system that is extensive of onshore faults and numerous offshore earthquakes.  
19.. What was the direction of the differential stress that created both of these features? (e.g. east-west direction? North –south?)The direction of the differential stress is northwards.  

20. Write one to two sentences that summarize your interpretations from above of how the rocks in the Trinidad, CO area were deformed. (3 pts)  Be sure to include the following:

The rocks in Trinidad were deformed as a result of plate movements under the Northern American plate which caused the crust of the earth to compress and eventually break (Viegas et al, 2012).

What are the deformation features that are observed? 

Deformation features observed includes green schist metamorphism and north vergent nappes.

 (b) What was the most likely differential stress?

Shear stress

(c) What was the direction of the differential stress?

East to west direction

21. Based on your observations of deformation in Trinidad, CO, is it possible that the deformation event here is related to either the event in Loveland, CO or in Boulder, CO?  Why or why not? (2 pts)

The event of Trinidad was as a result of two earthquakes that might have taken place in the same area and even possibly in the same fault.