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Snapshots

  1. Tidal lamination

    Snapshot Title: Tidal lamination
    Taken by: Peter Lea

    Image: Dakota Sandstone near Caineville, Utah
    Image Owner: Peter Lea



    Description:

    The thin, regularly alternating layers of fine sand (light) and carbonaceous mud (dark) likely reflect deposition by increasing and decreasing tidal currents, with the deposits escaping later disrupti...



  2. Abrupt boundary between coal and marine sandstone

    Snapshot Title: Abrupt boundary between coal and marine sandstone
    Taken by: Peter Lea

    Image: Dakota Sandstone near Caineville, Utah
    Image Owner: Peter Lea



    Description:

    This sharp boundary indicates a relative sea-level rise and erosion as the shore migrated landward. Note concentration of pebbles and other coarse material (lag) in sandstone.



  3. Shell lag in shoreface sandstone

    Snapshot Title: Shell lag in shoreface sandstone
    Taken by: Peter Lea

    Image: Dakota Sandstone near Caineville, Utah
    Image Owner: Peter Lea



    Description:

    Not in life position, concentrated by wave erosion.