ABSTRACT

The beach-ridge plain in the State of Tabasco, Mexico, is undergoing erosion today. It has not been growing for at least 50 years, and perhaps for as long as several centuries. Ten lines of evidence, including some severe limiting dates, substantiate this analysis. The large number of beach ridges, however, provides that, prior to the present epoch, there was a long interval of growth. The area has gone through a late Holocene history having 2 main parts: (1) a littoral economy of abundance of sand, during which the beach-ridge plain was built; and, (2) a littoral economy of scarcity of sand, during which the edge of the plain has been attacked by erosion.

This history coincides with that of other beach-ridge plains in North and South America. We conclude that the equilibrium beaches of the world have undergone a shift in the last few centuries, or are now undergoing a shift, from dominant deposition to dominant erosion. The problem of essentially world-wide coastal erosion is, therefore, getting worse.