Earth Science: Average Rate of Sediment Deposition

[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

[Borek]

How is rate of sediment deposition defined?

[ssshazam]

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

[Borek]

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

[ssshazam]

A) Rock B-Rock A = #
Take that #and 1.8/#
Answer: .00225

B) Rock D-Rock C = #
Take that #and 2/#
Answer: .00125

That's what I think it is.

[Borek]

Answer: .00225

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

[ssshazam]

meter/year

[Borek]

Now it looks OK.