Comparison of Amino Acid Racemization Geochronometry with Lithostratigraphy, Biostratigraphy, Uranium-Series Coral Dating, and Magnetostratigraphy in the Atlantic Coastal Plain of the Southeastern United States

Abstract

The results of an integrated study comprising litho- and biostratigraphic investigations, uranium-series coral dating, amino acid racemization in molluscs, and paleomagnetic measurements are compared to ascertain relative and absolute ages of Pleistocene deposits of the Atlantic Coastal Plain in North and South Carolina. Four depositional events are inferred for South Carolina and two for North Carolina by all methods. The data suggest that there are four Pleistocene units containing corals that have been dated at about 100,000 yr, 200,000 yr, 450,000 yr, and over 1,000,000 yr. Some conflicts exist between the different methods regarding the correlation of the younger of these depositional events between Charleston and Myrtle Beach. Lack of good uranium-series dates for the younger material at Myrtle Beach makes the correlation with the deposits at Charleston more difficult.

Sea level ~400 000 years ago (MIS 11): analogue for present and future sea-level?

“…In comparison with modern and Holocene (Unit Q1) deposits, McCartan (1988) believed that "The highest back-barrier deposits mark approximately the highest relative sea-level for each period of deposition". Backbarrier deposits up to 8 m occur in Unit Q2 (Wando Formation) and its late Pleistocene (MIS 5.5) age is based on Useries alpha ages on corals between 90 and 120 ka (McCartan et al, 1980;Szabo, 1985), amino acid ratios (McCartan et al, 1982), as well as relatively fresh minerals (McCartan et al, 1982). The Ladson Formation (Unit Q4) of Malde (1959) has back-barrier deposits up to 15 m. It is correlated with the Canepatch Formation at Myrtle Beach (SC) by a U-series alpha age of ∼450 ka and by mollusc and ostracode faunas (Cronin in McCartan, 1988).…”

Quaternary sea-level history of the United States

“…Most Atlantic Coastal Plain U-series studies have employed ahermatypic corals from higher-latitude sites, particularly in southeastern Virginia and central South Carolina (Figs 3, 16 and 17) (Mixon et al, 1982;Oaks et al, 1974;Szabo, 1985). Cronin et al (1981) discussed many of the paleoenvironmental implications of these ages, and McCartan et al (1982) discussed the relation of the U-series results to lithostratigraphic and other independent chronologic information.…”

“…Amino acid racemization has been applied by several workers to various stratigraphic problems in either local or regional studies of the Atlantic coastal (Corrado et al, 1986;Hollin & Hearty, 1990;McCartan et al, 1982;Wehmiller, 1982;Wehmiller et al, 1988Wehmiller et al, , 1992. In Figs 18 through 20, we present a summary of critical results from sites that have either independent stratigraphic or Useries chronologic information that provides a framework for interpretation of the racemization data.…”

“…A conceptual model for the relation of selected VLPG values to local stratigraphic sections is shown in Fig. 18, modified from McCartan et al (1982). Because both stratigraphic and geochronologic interpretations of the units portrayed in Fig.…”

Historical Evidence for Fluctuation in Levels of Hybridization

“…comm. ; see Cronin et al, 1981;McCartan et al, 1982). No radiometric dates are available directly from the Fish House clays.…”