Validity of sea-level indicators: A comment on “A new depositional model for the buried 4000 yr BP New Orleans barrier: implications for sea-level fluctuations and onshore transport from a nearshore shelf source” by F.W. Stapor and G.W. Stone [Marine Geology 204 (2004) 215–234

Abstract

The Holocene history of the SE Louisiana–Mississippi coast and a recently revised regional sea-level curve fail to support the concept of an abrupt Gulf-wide decline from +2.0 m to −1.5 m and regression, with barrier aggradation between 4.1 and 3.9 14C ka BP, triggered by massive onshore sediment transport. A subsequent rapid rise followed by minor oscillations are equally unsubstantiated. Suggestions for an overwhelming role of onshore transport during the assumed regression or otherwise may not be justified. A small hardcrust lens in the continuous subaqueous barrier sequence does not prove major fall in sea-level, regional regression and subaerial exposure. Elevation and lithofacies of Florida shore scarps and radiocarbon-dated beach ridges fail to support sea-level fluctuations. The presented paleogeographic and sea-level models indicate continuous shoal and associated island formation between ca. 5.2 and 4.0 14C ka BP, uninterrupted by sea-level decline. Rapid progradation of a Mississippi River–St. Bernard delta lobe terminated barrier development.