Original paper

Upper Cretaceous (Cenomanian-Turonian and Turonian-Coniacian) open marine plattenkalk deposits in NE Mexico

Ifrim, Christina; Stinnesbeck, Wolfgang; Frey, Eberhard

Abstract

In NE Mexico, the Cenomanian-Turonian plattenkalk of Vallecillo (state of Nuevo León) and the Turonian-Coniacian plattenkalk of Múzquiz (state of Coahuila) yield abundant fossil vertebrates and invertebrates with an exceptional preservation of soft parts. Inoceramid bivalves are the only benthic organisms in both deposits. They allow for detailed biostratigraphic subdivisions, precise dating and correlation with biozonations based on ammonites and foraminifers in both sections. In contrast to many other plattenkalks, the Mexican sediments were deposited in an open marine shelf environment, in a distance of >200 km from the nearest coast. Both Konservat-Lagerstätten formed near the southern opening of the Western Interior Seaway and contain mixtures of Western Interior Seaway and Tethyan faunal elements.

Keywords

cenomanian-turoniankonservat-lagerstättenmuzquizmexicoplattenkalkturonian-coniacianopen marine shelf environmentvallecillo