Stratification and sedimentation in complex vegetated coastal dunes, Sable Island, Nova Scotia

Abstract

A descriptive code for analysing the internal structure of vegetated coastal dunes is presented. The code is based upon three elements—grain size, stratification, and the nature of plant remains. It is used in an analysis of the dunes on Sable Island, Nova Scotia. A description of the stratification within the older dunes of the island provides the basis for a genetic interpretation of the processes operating throughout their history. Particular importance is attached to the role of vegetation in deposition. Four phases of dune development, each with distinct styles of stratification, are recognized in the Sable Island dunes. The first consists of tractional and grainfall deposition within very sparse vegetation. The second phase is dominated by grainfall deposition through increasingly dense vegetation. The third phase is represented by a paleosol. Finally, the fourth phase consists of horizontal, parallel and wavy laminated beds of loosely compacted, finer sand which result from grainfall deposition through dense vegetation.