A NEW LOOK AT THE LATE CRETACEOUS-EOCENE STRATIGRAPHY OF THE CENTRAL GEORGIA, UPPER COASTAL PLAIN

The world-class kaolin deposits are found in late Cretaceous-Eocene sedimentary rocks in the Georgia Upper Coastal Plain (UCP). The recent discovery of rare-earth element resources in these mined kaolins has increased attention to the stratigraphy of the late Cretaceous-Eocene strata in the UCP. Up-to-date lithologic correlations and the mapping of depositional environments will help refine our knowledge of the sedimentological processes forming these strata. The knowledge gained will be useful for the further exploration of critical mineral deposits in the UCP.

This present study examined late Cretaceous-Eocene stratigraphy of the central Georgia UCP based upon new field work extending in the dip-parallel direction and proximal to the Fall Line. The outcrops were located along a transect that trended with the direction of the Oconee River and located 10 miles east, crosscutting the Sandersville mining district from northern to southern Washington Co, GA. This dip-parallel transect (Q-Q’) was perpendicular to the strike-parallel transect in previous study (Huddlestun and Hetrick, 1986) and provides a more comprehensive view of central Georgia UCP stratigraphy.

Results of the study include new lithologic correlations showing both litho- and ichnofacies in the stratigraphy of this transect. Correlations included lithologies such as beach placer heavy-mineral sands, fossiliferous sands and limestones, kaolin and other clay-rich formations. Localized correlations included channel scour and fill deposits (proximal to the Fall Line) and intertidal channel inlets with skolithos ichnofacies (distal to the Fall Line). These data provide a basis for future lithologic and stratigraphic studies in the Georgia UCP. The new insights are noteworthy when considering the growing interest in critical mineral resources beyond kaolin clay, and the further exploration and development of the rare-earth element resources in these strata.