GEOLOGIC MAPPING OF NORTHEAST FLORIDA: PORTIONS OF THE FERNANDINA BEACH AND LAKE CITY 100K QUADRANGLES

In 2020, the Florida Geological Survey was awarded a 2-year project through the United States Geological Survey’s (USGS) Earth Mapping Resources Initiative. The project focuses on surficial geologic mapping of the Trail Ridge heavy-mineral placers in northeast Florida, referred to herein as the Florida Focus Area (FFA). This area includes portions of the USGS 1:100,000 scale Fernandina Beach, Okefenokee Swamp, and Lake City quadrangles; areas slated for completion under the Florida Geologic Statewide Mapping Initiative.

Existing regional geologic maps have been published at various scales. The FFA overlaps an area where previously funded STATEMAP projects have produced surficial geologic maps, yet detailed geologic mapping is needed to better understand the genesis and distribution of heavy mineral placer deposits that contain both titanium and rare earth element bearing minerals. This study supports the ongoing FGS statewide 2D and 3D mapping initiative, informs natural resource managers about critical heavy mineral deposits, informs industry about the distribution of potential mineable resources, and improves scientific understanding of the genesis of heavy mineral placer deposits in the FFA. Furthermore, these maps will be useful tools for local land-use planners, resource managers, and environmental scientists to use when making decisions about future growth and development, groundwater allocation, resource conservation, and other issues affecting the citizens of Florida.

Data collected for the completion of this study will support ongoing USGS projects which utilize heavy mineral analyses in provenance studies within the Atlantic Coastal Plain of eastern North America. The types of analyses proposed, will provide insight into the variety and abundance of critical minerals present, their source(s), and offer a more detailed characterization of their extent and concentrations, thus providing a better understanding of the region’s geologic framework.