A Cerion-based chronostratigraphy and age model from the central Bahama Islands: Amino acid racemization and 14C in land snails and sediments

Paul J. Hearty, Darrell S. Kaufman

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The taxonomy of the land-snail genus Cerion, and the relevance of hundreds of shell forms to phylogenetic and evolutionary processes has been the subject of much discussion over the past few decades. Fundamental to understanding evolutionary trends is the independent confirmation of the age, biostratigraphic, and chronostratigraphic order of a comprehensive set of fossil forms. Amino acid racemization (AAR) is a geochronological tool applicable to dating living and fossil Cerion shells. The extent of racemization of aspartic acid (Asp D/L) and glutamic acid (Glu D/L) were determined for 507 Cerion shells dating between the early last interglaciation (marine isotope stage (MIS) 5e, c. 125 ka) and the present from the Bahamas. The AAR data based on Cerion support the established morphostratigraphic succession of deposits younger than MIS 5e and provide greater resolution, particularly for biostratigraphic successions of Holocene age. Age models were constructed for Asp and Glu using D/L values paired with 14C ages and historical collection dates from 23 Cerion shells. In addition to the relative-age time series, the Holocene age models developed from D/L Glu and Asp apply to the last 7 ka and geographically within the central Bahamas. In two case studies, large numbers of AAR-generated ages provide insights into the age structure of accretionary soils and rates and age constraints on evolutionary processes related to Cerion land snails.

Original languageEnglish (US)
Pages (from-to)148-159
Number of pages12
JournalQuaternary Geochronology
Volume4
Issue number2
DOIs
StatePublished - Apr 1 2009
Externally publishedYes

Keywords

  • Amino acid racemization
  • Bahamas
  • C chronology
  • Cerion land snails
  • Epimerization
  • Numerical age model
  • Quaternary

ASJC Scopus subject areas

  • Geology
  • Stratigraphy
  • Earth and Planetary Sciences (miscellaneous)

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