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Structural Geology: Fault Correlation

  1. Feb 15, 2010 #1
    (I moved this from the Homework section. I hope it is okay I am posting here.)

    1. The problem statement, all variables and given/known data
    We are given six cross sections each spaced 2km apart and from these we are supposed measure the slip of the fault, and map the hanging-wall and footwall cutoffs to another worksheet that is the map view of the cross sections. Once we have mapped all of the cutoffs and measured the slip of each fault we are supposed to connect the faults according to the amount of slip the fault has.

    Here is a link to a file sharing website containing the cross sections and the total problem statement.

    http://www.mediafire.com/myfiles.php" [Broken]

    The file "Lab5_2010" is the whole problem statement.
    The file "Lab5_crossSections" has all of my slip measurements on each of the cross sections
    The file "Lab5-My_attempt" is my attempt on connecting the faults so far.

    I am not sure if I am connecting the faults correctly. Can someone please check that for me?
    Also, how could I answer question 4 on the file "Lab5_2010"?

    Thanks in advance,
    KEØM
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 15, 2010 #2

    Evo

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    Staff: Mentor

    If we allow this here, you will still need to show what you have done in trying to solve this yourself. We can't advise you until we see where you are getting stuck.
     
  4. Feb 15, 2010 #3

    Redbelly98

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    I can't see your files, instead I get redirected to the home page of mediafire. KEØM, I am guessing either one needs to have an account there in order to see your files, or your link has to be more direct. If I did have a mediafire account, that link would probably take me to my own files, not to yours.

    I think it is unlikely you will get help unless you find another way to show us the files you want us to see.
     
    Last edited by a moderator: May 4, 2017
  5. Feb 15, 2010 #4
    Thanks for the reply

    My attempt at linking the fault cutoffs is in the file "My_Attempt" and my measuring of the slip and mapping the cutoffs on the cross sections is in the file "Cross Sections."

    The main steps I took to do this are:

    1. Extrapolate the cutoffs to the surface on the cross sections, drawing in the hanging-wall and foot-wall symbols.

    2. Measure the distance along the fault in between the cutoffs (using a ruler and the conversion factor 1cm = 500m) to get the amount of slip the fault has.

    3. I then folded my cross section paper along the cross section surface line and placed that on my map paper making tick-marks on the map paper every time crossed a cutoff. (i.e. I folded along line 2 on the cross section and then put that on top of line 2 on the map paper. Similar to making a topographic profile)

    4. Now I am trying to connect the cutoffs on the map that have similar slip values. I have heard that this is pretty ambiguous but I just want to make sure I am somewhat right.

    I am also confused on where the would be the best place to drill for oil on the map assuming that all of the faults seal (i.e. the don't allow fluid flow) and that layer B is a sand reservoir with a good top seal.

    Thanks again and sorry for the lack of work shown,

    KEØM
     
    Last edited: Feb 15, 2010
  6. Feb 15, 2010 #5
    Last edited: Feb 15, 2010
  7. Feb 16, 2010 #6
    I should start with the caveat that I am not a structural geologist, and although I have taken structural geology courses and have been in the field and made my own geological maps, I haven't done any such thing for a good three or four years now. Feel free to ignore my comments.

    Overall I would say not too bad. The faults you have connected seem sensible in that they at least point in a consistent direction, and in general the throw is greatest in the middle of the fault.

    I think your interpretation looks a bit contrived, especially in the middle where all the fault tips seem to converge, that seems unphysical to me. Be brave, link those tips and create a bifurcating fault.

    My tips would be: try to look for a more simplistic, and elegant fit; look at the cross sections and try to visualize the structure.

    Good effort though.
     
  8. Feb 16, 2010 #7
    Thanks for the reply billiards. Your advice helps and I think it will make my map more accurate.

    Where would I drill to hit most oil? Would it be where the most faults are? Or where the least are? The instructor never covered this in class and the textbook is no help either.

    Thanks for taking the time to look at all those files!

    KEØM
     
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