27 January 2010

3 Responses to “?”

  1. BrianR Says:

    whoa … whenever I see something bizarre in rocks I can’t explain I usually end up muttering ‘some weird diagenetic feature’

  2. In terms of ‘gross morphology,’ my visual match was a fold verging on ptygmatic, with the lighter-colored layer (resistant to erosion) being more competent than the surrounding gray matrix. Is there significant deformation elsewhere in the dolomite? In other words: what’s the reason to think this is a sedimentary structure rather than a tectonic structure?

  3. Neil Says:

    Thanks for the comments. Calling it a “sedimentary structure” was really just imprecise hedging by a fake geologist (me).
    In retrospect I agree with the growing consensus that it is a diagenetic/deformational structure.

    I don’t know much about the tectonic history of the Reed Dolomite – but given it’s age (neoproterozoic) and location (White Mountains, Basin and Range) I’m sure that it has been through a lot. I didn’t even realize ptygmatic folds could form in dolomite!

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