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Sequence Stratigraphy And Depositional Facies Of Lower Ordovician Cyclic Carbonate Rocks, Southern Missouri, U.S.A., Robert Brandon Overstreet, Francisca Oboh-Ikuenobe, Jay M. Gregg

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Lower Ordovician cyclic carbonate strata of southern Missouri were deposited in a warm, shallow, epeiric sea on a fully aggraded carbonate platform. Sedimentological characteristics distinguish the Jefferson City and Cotter dolomites from the underlying Gasconade and Roubidoux formations. Mixed carbonate-siliciclastic sedimentation characterizes the Roubidoux Formation, with sandstones accounting for up to 60% of sedimentation. The Gasconade, Jefferson City, and Cotter dolomites exhibit an increased occurrence of chalcedonic chert nodules in very similar shape and texture to the gypsum and anhydrite nodules common on modern sabkha supratidal flats. Casts of halite and ghosts of gypsum laths also exist in the Jefferson …