Chevron ridges and runup deposits in the Bahamas from storms late in oxygen-isotope substage 5e

Paul J. Hearty, A. Conrad Neumann, Darrell S. Kaufman

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

Landward-pointing V-shaped sand ridges several kilometers long are common along the windward margin of the Bahama Islands. Their axes share a northeast-southwest trend. Internally, the ridges contain low-angle oolitic beds with few erosional truncations. Commonly interbedded are tabular, fenestrae-rich beds such as those formed by the sheet flow of water over dry sand. Defined here as 'chevron ridges,' these landforms appear to have originated in the rapid remobilization of bank margin ooid bodies by the action of long-period waves from a northeasterly source. Deposits along adjacent coastlines also preserve evidence of the impact of large waves. Reworked eolian sand bodies preserve beach fenestrae and hydraulic scour traces up to +40 m on older ridges. On cliffed coasts, 1000-ton boulders have been thrown well inland, recording the impact of large waves. Amino acid ratios confirm a correlation of the ridges across the archipelago, while stratigraphy, spacing, and cross-cutting relationships indicate emplacement as sea level fell rapidly from the substage 5e maximum at or above +6 m.

Original languageEnglish (US)
Pages (from-to)309-322
Number of pages14
JournalQuaternary Research
Volume50
Issue number3
DOIs
StatePublished - Nov 1998

Keywords

  • Bahamas
  • Giant boulders
  • Interglaciation
  • Sea level
  • Substage 5e

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Earth-Surface Processes
  • Earth and Planetary Sciences(all)

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