Heavy-Mineral Mining in the Atlantic Coastal Plain of Florida and Georgia and What Deposit Locations Tell Us about Ancient Shorelines

Economic mining of heavy-mineral sands has a long history in the Atlantic Coastal Plain. From the early part of the 20th century to date, a total of 11 heavy-mineral ore bodies either have been or currently are being mined in Florida and Georgia. Additional deposits have been lost to mining, primarily due to cultural events, or are waiting future exploitation. These deposits have different origins, as has been seen during recent evaluations of the deposits, some in contrast to conventional depositional models. It has long been believed that deposits formed along shorelines at the height of major marine transgressions, but it is now postulated that some heavy-mineral-bearing sands accumulated on regressional beach ridge plains during periods of temporary stillstands or during slight transgressions that accompanied general marine regressions. Although many deposits might indeed have formed as conventional beach placers, others might have accumulated as deposits associated with fluvial–deltaic regimes or with vegetational baffles. These different origins are reflected in the chemical and physical characteristics of the deposits as well as grain size of the sediment. The relationship of the heavy-mineral mineral deposits (location) to the landforms in the Atlantic Coastal Plain provides insight into the ancient shorelines of the Atlantic Coastal Plain.