ABSTRACT

Gulf Coast Miocene sediments are among the most lithologically complex in the entire Nation. This varied lithology stems in part from multiple source areas that were active during this interval but also reflects major tectonic events that influenced depositional patterns throughout the Gulf Coast during the Miocene. Because fossils are scarce or lacking in many of the units, important questions relating to a number of geological problems have been addressed by analysis of sediment mineralogy. Examples are discussed illustrating how such analyses can be used to: (1) clarify stratigraphic relationships between units in contact, (2) define environmental conditions in the depositional basin, (3) reconstruct paleoclimate conditions, and (4) identify provenance areas. A major anomaly in the mineralogy of central Gulf Coast Miocene sediments is explained by postulating a major "ancestral Tennessee River" originating in the southern Appalachians and flowing southwestward across Alabama and Mississippi to a terminus in the ancient Gulf of Mexico.