Geologic Hazards Web-Lab

 

Please clip and complete this lab text in Microsoft Word (or other word processor).  

 

Part 1 General

a.     What are the names of the faults on either side of the Cristianitos Fault?

 

b.    How is the Cristianitos Fault different than the surrounding faults as described in #1? 

 

c.     Describe how slumps form, their features, and what factors may cause them to move faster or slower.

 

d.    What potential future threat does slumping pose in this area? 

 

 

Part 2 Describing the Sedimentary Rocks

Describe the four sedimentary rock formations that we observed on this trip.

a.     Alluvial Deposits

 

b.    Marine Boulder Bed

 

c.     Monterey Formation

 

d.    San Mateo Formation

 

Part 3 Ages of Rock Formations

Monterey Formation: 15 MYO based upon radiometric dating of the volcanic ash beds found within the formation. 

 

San Mateo Formation: 5 MYO based upon fossil data.

 

Marine Boulder Bed:  The Marine Boulder Bed contains fossils that can be age-dated using radiometric data. U-xxx (parent material) is contained in the shells of animals that are fossilized in this unit. 

 

Assume these values: These are not the actual values but we will use them for this exercise

·      Parent: U-xxx is 50%.

·      Daughter: Th-xxx is 50%.

·      The half-life of U-xxx is 125,000 years

 

If you are confused see the Radiometric Dating Tutorial.

 

a.     Number of half-lives elapsed?  ___________________________

 

b.    What is the age of the Marine Boulder Bed?___________ years old. SHOW YOUR CALCULATIONS FOR CREDIT!

 

If you get something that is not between 10,000 and 500,000 years you are not doing this correctly. Reread the Radiometric Dating Tutorial and try again.

 

Part 4 The Cristianitos Fault

Using relative and radiometric age dating data obtained in this lab. Answer the following questions and EXPLAIN the logic you used to get to that answer.

****Hint: Faults are younger than the rocks they cut, so what rocks does the fault cut? Which rocks does it not cut? That will give you the range of ages that the fault could have moved.

 a.     What is the oldest date the Cristianitos Fault could have moved? Why?

 

b.    What is the most recent the Cristianitos Fault could have moved? Why?

IF YOU DON’T UNDERSTAND PART 4 TO THIS POINT AND CAN’T FIGURE IT OUT, YOU MAY WANT TO CONTACT ME FOR HELP!

c.     Faults are considered active if they have moved once in the last 35,000 years based upon State of California engineering guidelines.  Based upon this and your answers above, would the State of California consider the Cristianitos Fault to be active and therefore a risk to the nuclear powerplant?

 

d.    What other hazards are possible geologic hazards are possible for the nuclear powerplant?  Try to come up with at least 2 different hazards. Explain your responses.

 

e.    What part of this Web-lab would you improve?  Did you find particular parts hard to follow or understand?

 

 

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