COASTAL PALEOECOLOGY OF THE CRETACEOUS WOODBINE FORMATION (CENOMANIAN) OF NORTH CENTRAL TEXAS

The Woodbine Formation (Cenomanian: 94-98 Mya) of North Central Texas is known for its unique fossil assemblage from a little studied stage in Earth history. Research at a productive fossil locality located within Tarrant County called the Arlington Archosaur Site (AAS), has determined that the paleoenvironmental setting is that of an ancient coastline with an intertidal to brackish water system. The coastal system has a “White Zone” a section of coastline associated with a coastal environment where fresh water deposits and salty marine deposits maintain equilibrium within the tide cycles which is supported by invertebrate taxa biomarkers and trophic structure. The sediments were deposited on a low lying coastal plain along the Rudradian peninsula by delta channel bifurcation and avulsion. The coastal system was part of the Greenhorn cycle, an interior seaway that ran through North America during the high stand of the mid-Cretaceous. The Woodbine exposures preserve a diverse ecosystem that was well suited for a delta plain including: turtles, crocodyliforms, dinosaurs (theropod and ornithopod, such as Protohadros byrdi), mammals, and other organisms such as invertebrates. However, an under addressed issue with the Woodbine Formation is the understanding of the holistic coastal ecology and diversity of Cenomanian Cretaceous ecosystems and the finer points of deltaic-coastal geology and with the ongoing research at the AAS and other localities a more precise reconstruction can be created.