# Earth Science: Average Rate of Sediment Deposition

1. Sep 27, 2011

### ssshazam

1. The problem statement, all variables and given/known data

Link of picture that the information below is referring to: http://i56.tinypic.com/283lv.jpg
You encounter the sedimentary rock outcrop shown above while you are out hiking. You collect rock samples from points A-D and go back and measure their ages in your isotope lab.
A=10.1251 million years old
B=10.1259 million years old
C=10.1262 million years old
D=10.1278 million years old
From detailed analyses of the rock textures and minerals found in the rocks, you determine that all of the rocks were formed from sediments deposited in a floodplain environment.

A) Calculate the average rate of sediment deposition for the unit sampled by rocks A and B (show your work and give units):

B) What is the average rate of sediment deposition for the unit sampled by rocks C and D (show your wok and give units):

C) What changes in the local environment do you think might have caused this change in deposition rate?

2. Relevant equations
None that I know of.

3. The attempt at a solution
I don't know how to approach this problem at all.

Thanks

Last edited: Sep 28, 2011
2. Sep 28, 2011

### Staff: Mentor

How is rate of sediment deposition defined?

3. Sep 28, 2011

### ssshazam

I'm not sure... that's all the information that's given.

4. Sep 28, 2011

### Staff: Mentor

It should be defined in your books, or in your notes. If it is not - think, what IS rate of sediment deposition?

5. Sep 28, 2011

### ssshazam

A) Rock B-Rock A = #
Take that #and 1.8/#

B) Rock D-Rock C = #
Take that #and 2/#

That's what I think it is.

6. Sep 29, 2011

### Staff: Mentor

0.00225 of what? Fathoms per fortnight? mph? Inches per year?

7. Sep 29, 2011

### ssshazam

meter/year

8. Sep 29, 2011

### Staff: Mentor

Now it looks OK.