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The AAPG/Datapages Combined Publications Database
AAPG Bulletin
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Five major environments of deposition were present along the outcrop trend of the Salem Limestone in south-central Indiana. These environments are based on lithic and biologic distributions.
Three separate regions existed during deposition of lower and middle Salem sediments. The northern region was restricted, as indicated by the presence of argillaceous, dolomitic, bryozoan calcarenite. This was a shallow sea which connected with the Michigan basin where evaporite deposition was occurring. The central outcrop region was one of open circulation where algal-mollusk and echinoderm-bryozoan sparry calcarenite was deposited. Distribution of the calcarenite indicates a regression toward the south. The Indiana building stone is quarried mainly from this facies. The southern region was the site of extensive large-scale (30 feet of relief) sparry calcarenite sand bars as indicated by the existence of macro-cross-beds.
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Inter-sand-bar deposits consist of carbonaceous dolosiltite which does not contain skeletal grains. A sample transect from sand-bar crests to inter-bar basins shows a continuous, progressive gradation from sparry calcarenite to dolosiltite.
During deposition of upper Salem sediments, a fine-grained calcisphere calcarenite overlapped all three facies described above. This facies was deposited in restricted, shoaling conditions, as indicated by the presence of dolomite, quartz silt, and clay minerals.
The final phase of Salem deposition is represented by a thin but persistent, laminated, argillaceous dolosiltite. Scour-and-fill structures, dolomite rhombs, and a lack of fossil grains indicate that this was an intertidal mud flat deposit comparable with New York Devonian "waterlimes."
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