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Analyses show that the Permian Carlsbad formation of New Mexico is dolomite. The stratigraphic relation of the Carlsbad to other contemporaneous and contiguous deposits suggests that all ions in sea water transgressing the reef area available to form calcium carbonate precipitated to make the Capitan and Carlsbad formations. The flat-lying Carlsbad deposits were converted before burial into dolomite through contact with strong magnesian brines from the back-reef. Most of the Capitan remained unaffected. The relative position of these limestones and dolomites to contemporaneous deposits indicates a chemical sequence of deposits caused by evaporation of sea water and that organisms flourished only in congenial environments. The pisolites are of physio-chemical origin with l ttle positive evidence for organic associations. The pisolites are compared with the Carlsbad Cavern cave marbles.
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