Origin of beach ridges: Reply

Abstract

The important difference here is whether or not sea level can change by the right amounts and on the right schedule. Curray says “no”. However, various reports in the recent literature (cited below) show that he is mistaken. Likewise his concept of uniform global change is not supported by the published data. Sea level does change, at relatively short intervals (years, decades), by amounts that are adequate to produce individual sandy beach ridges, and this change is not uniform at all places. My citation of Curray (and others) for an 18.6-year period in one sandy beach ridge plain was an inadvertent error, and I apologize for it. My caveat that we do not know that his study area — in a well-known modern deformational belt — was completely stable throughout the Holocene, is still valid. The corollary: Data obtained from such areas may not be as useful as information from other areas; therefore the presumed 18.6-yr cycle is suspect ab initio. Curray's hypothesis that beach ridges are initiated by what is basically the suggestion of de Beaumont, does not provide a suitable model, as is discussed below. Finally, Curray disregards the detailed granulometric analysis which was the basis for most of my work. This modern analysis can stand alone, if necessary, and is not affected in any significant way by warping or other small deformation. However, the present availability of records of small modern sea level changes confirms the reasonableness of the timing and magnitudes which were deduced as part of the granulometric work.