Depositional Environment of the Heavy-Mineral Deposits of Bailey, North Carolina, U.S.A

Document Type

Article

Publication Date

2013

Publication Title

Southeastern Geology

Abstract

The Bailey, North Carolina, heavy-mineral deposits cover 12.9 square kilometers and contain 5.72 million metric tons of heavy minerals. The sediments comprising this deposit average 6.2 meters thick and contain an average of 4.72 weight percent heavy minerals. Valuable heavy minerals comprise 65 to 70 percent of the heavy-mineral suite and are comprised of ilmenite, leucoxene, rutile, and zircon.

Most of the Bailey heavy-mineral concentrations lie south, southeast, east, and northeast of the town of Bailey, North Carolina. In this area, unconsolidated Cenozoic sediments of the inner Coastal Plain unconformably overlie the roughly circular Upper Paleozoic Sims pluton which intrudes the older slate belt rocks of the region. The Kenly and Hawley heavy-mineral deposits, south of the Bailey deposits, are probably a continuation of the Bailey deposits. The separation of the two areas of heavy-mineral concentrations most likely is the result of post-depositional stream erosion. It is hypothesized that tides and fluvial processes served as the main agents for concentrating the heavy minerals. It is also hypothesized that the presence of delta and salt water marsh environments resulted in the accumulation of the majority of the kaolin clay that is present. Heavy minerals of the Bailey deposits were probably carried by the Neuse River and deposited in a delta at the edge of a salt marsh. A combination of the crossbedding and Ophiomorpha strongly suggest that the ancient sediments were deposited in subtidal high-energy shoals associated with a tidally-dominated channel of moderate size, such as an inlet or sound associated with barrier islands. Thus, the clay and heavy-mineral concentrations seem to have been partially the result of tidal and fluvial processes operating in a shallow marine to brackish (salt marsh) depositional environment. The Sims pluton appears to have played a role in influencing the path of the Neuse River and, hence, the formation of the Bailey deposits. Based on the pollen present, the Bailey heavy-mineral deposits are probably of Late Pliocene or Early Pleistocene age.

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