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How do i determine if a rock is qtz-norm, ol-norm, hy-norm or ne-norm?

  1. Oct 1, 2009 #1
    i have a rock that has been chemically anaylzed, all oxides are determined. the question is asking me to determine which is qtz-normative,, olivine-norm, hypersthene-norm or nephtaline-norm. ho do i determine which one it is based on the data i am given. the question also gives norm values for many minerals
  2. jcsd
  3. Oct 1, 2009 #2


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    First, convert the weight % of each element to molecular %. Then allocate the molecular % to idealized mineralogies in a logical progression. If there is a silica deficit, then there are more calcs necessary until the deficit is eliminated.

    There are Excel spreadsheets available on the internet for this, but don't try if you're not good with chemistry. There's also more than one way (convention) to do this.
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