Paleoenvironmental Interpretations Based on Vertebrate Fossil Assemblages: An Example of their Utilization in the Gulf Coast

Abstract

ABSTRACT Foraminifera, ostracodes, and various invertebrates have traditionally been utilized to define and interpret paleoenvironments in the Gulf Coast. In the last decade, studies have demonstrated the value of vertebrates, especially fish otoliths or earstones, in the determination of ancient environmental conditions. This study analyzes the use of fish otoliths and other vertebrate remains in the paleoenvironmental interpretation of the Mint Spring Formation (Vicksburg Group, Oligocene) in Rankin County, Mississippi. The paleoecology of the formation was ascertained based on otoliths and related vertebrate material obtained from three sampled intervals. The vertebrate fossil assemblage included remains from cartilaginous fishes, bony fishes, reptiles, and mammals. The vertebrate-based paleoecology was compared to paleoenvironmental parameters based on foraminifera, macroinvertebrates, and the sedimentological data. The vertebrate-based interpretations agreed quite well with the invertebrate-based data for the formation and provided further evidence of the usefulness of vertebrate-based paleoecology in the Gulf Coast. The fish otoliths provided more detailed data about the paleoecology than the remains of the other vertebrate groups. Although the vertebrate remains proved to be valuable and accurate in the interpretation of the paleoenvironment, limitations on their utilization were noted.