THE ORIGIN OF BEACH RIDGES AND FOREDUNES AND THEIR RELATIONSHIPS TO SEA LEVEL

The origin of beach ridges (and occasionally foredunes) has been debated in the literature with multiple evolutionary mechanisms being suggested. Mechanisms include origin via plant growth onto the backshore and aeolian deposition forming foredunes, formation by storm waves, spring tide bar and berm formation with or without so-called aeolian decoration, formation due to sea level changes, and a variety of others. A review of these will be presented.

A major question is how are beach ridges or foredunes related to sea level (if at all), and if the predominant formative mechanism is known, can Holocene sea levels be determined from an analysis of the ridges and their underlying sediments or their stratification. Data collected in Australia, Canada, Brazil and the USA Gulf coast will be presented to demonstrate the origin of “beach ridges”, and their relationship and position relative to sea level.