Abstract: “Sable Island is situated on the edge of the Continental Shelf 100 miles east of the coast of Nova Scotia. The island is the only emergent point on the outer banks of the Scotian Shelf. It is 24 miles long and consists entirely of unconsolidated Pleistocene sands of glacial and wind-blown origin accumulated near the Continental Slope during the stages of lower sea level. The present morphology results from a reworking of Pleistocene dunes by wind, waves and tidal currents in conjunction with recent changes in sea level. Detailed surveys between 1952 and 1965 show that the bars at both ends of the island are continuously modified; the central dunes are not being altered extensively. This is surprising because of the particularly strong wind and wave currents in this area. Why have the sands not been dispersed into the ocean? The following explanation is proposed: a paleosol of probably Pleistocene age underlies the dunes along the length of the island. It consists of a humus-peaty former surface horizon 20-30 cm thick, underlain by yellow-brown, somewhat oxidized eolian sands. The organic layer acts as a resistant “cap”; it also enables some vegetation cover to develop on the otherwise sterile sand. In areas where the organic horizon of the paleosol is missing, such as the bars at the end of the island, dunes are rapidly shifted, leveled, and breached. The highest dunes, some of them 75 ft above sea level, are preserved only where the paleosol is present.”
