Late Cenozoic marine deposition in the United States Atlantic Coastal Plain related to tectonism and global climate

Major hiatuses in upper Cenozoic marine deposits in the United States Atlantic Coastal Plain are recognized on the basis of molluscan faunal changes at erosional unconformities. These hiatuses generally coincided with periods of global cooling and ice sheet formation. Such hiatuses provide information to supplement global climatic data. Major hiatuses are recognized within the early Miocene (23-20 m.y. ago), at the end of the middle Miocene (??? 11-10 m.y. ago), at the end of the late Miocene (???6.5-5 m.y. ago), at the end of the early Pliocene (???4.0-2.5 m.y. ago), at the end of the late Pliocene (???1.9 or 1.8 m.y. ago), within the Pleistocene (???1.1-0.5 m.y. ago) and several times within the last 0.4 m.y. Estimates of the amount of water contained in ice sheets at different times in the Pliocene and Pleistocene facilitate calculation of probable minimum sea levels on the Coastal Plain during different high stands of the sea. The altitudes of dated shoreline deposits in the Atlantic Coastal Plain show that the amount of uplift in the Cape Fear area has averaged at least 1.3 cm per 1000 years since the beginning of Pliocene time. The Coastal Plain of Georgia has apparently experienced relatively little vertical deformation during this same time. ?? 1981.