Significant unconformities and the hiatuses represented by them in the Paleogene of the Atlantic and Gulf Coastal Province

A biostratigraphic, chronostratigraphic, and magnetostratigraphic model has been calibrated to produce a new time scale for the Paleogene. The model gives the biostratigraphic position and duration represented by significant unconformities in three areas of the Atlantic and Gulf Coastal Province: 1) western and central Alabama; 2) South Carolina; and 3) central Virginia to southwestern Maryland. In these areas, the most significant unconformity, in terms of duration represented and lateral extent, is found in the lower Eocene. In Alabama, this unconformity centers around 51.4 m.y. and represents a hiatus of about 1.4 m.y. In South Carolina, this unconformity centers around 50.3 m.y. and represents a hiatus of about 10.0 m.y. In Virginia-Maryland, the lower Eocene unconformity centers around 49.0 m.y. and represents a hiatus of about 7.3 m.y. A significant unconformity exists between the Cretaceous and Tertiary in all three areas. On the Atlantic coast the Cretaceous-Tertiary unconformity represents some missing Danian and significant missing Maestrichtian. In Alabama, however, there is virtually a complete Danian section and it is only most of the upper Maestrichtian that is missing. There are significant regional unconformities in all three areas.