Contrasting beach-ridge systems in different types of coastal settings

Abstract

Beach-ridge systems are geomorphological features common in every type of coast and have been widely interpreted as geo-archives of past sea-level, climatic, or tectonic changes. These relict morphological elements are well-known by their facies, architecture, stratigraphy, and evolution. However, the coastal context where beach ridges are formed has never been evaluated. Coastal beach-ridge systems were classified into four main types corresponding to deltaic strandplains, non-deltaic strandplains, spits, and barrier islands. Our study consisted of three scales of analysis: (1) the entire beach-ridge system; (2) beach-ridge sets; and (3) individual beach ridges. Several beach-ridge systems having formed in different types of coastal settings are compared by their present characteristics. Geomorphic data generated from processing and interpreting satellite images combined with previous studies are used to quantify multi-scale attributes of beach-ridge systems. These attributes include the area, length, width, number of sets, number of ridges per set, set rotation, ridge spacing, and ridge elevation. Our findings demonstrate that significant differences define beach-ridge systems including deltaic strandplains, large non-deltaic strandplains, small non-deltaic strandplains, large spits (cuspate forelands), small spits (flying spits, bay-mouth spits and tombolos) and barrier islands. A more comprehensive characterization of the factors controlling beach-ridge variability will improve our ability to recognize the sedimentary record of ancient of these systems. The proposed basic platform can be used to isolated different beach-ridge types and systems to facilitate future process and morphodynamic studies.