GEOMORPHOLOGY OF PARABOLIC DUNES IN THE ALBANY PINE BUSH DUNE FIELD, NEW YORK

The Albany Pine Bush Preserve (APBP) consists of sand dunes and wetlands in a pine barrens landscape that is uncommon on the east coast of North America. The pine barrens ecosystem is fire dependent and provides unique habitats to rare and diverse species including the endangered Karner blue butterfly (Plebejus samuelis). Sand dunes of the APBP formed on top of lacustrine sediments of former glacial Lake Albany. The retreat of the Laurentide Ice Sheet left behind glacial landforms that are overlain by dunes and today the dune field is partially eroded by a stream system. In this collaborative research we mapped in detail the full extent and character of sand dunes using recent high-resolution (1m) LiDAR data and associated hillshade models. Mapping revealed that dunes occur over a wider area than previously shown, >85 km². We collectively refer to these dunes as the Albany Pine Bush dune field.

New interpretation includes dune crests, slip faces on leeward sides of dunes, and polygons of continuously overlapping dune areas of both leeward and windward sides. All interpretation was completed in ArcGis Pro. Dunes are commonly U-shaped with taller heads compared to much lower relief arms and overlap considerably. Isolated dunes are rare. Dune limbs lie generally parallel with overall remarkably little variation in ESE orientation across the field and range from 0.1 to ~2 km long. In addition to dunes, enigmatic circular sand “pits”' were mapped on dune slopes, crests, and interdune areas that are up to 3m across and a meter deep.

Dunes formed from WNW winds consistent with present-day prevailing winds. There is no evidence that dunes formed from NE winds as are found in Saratoga Sand Plains ~50 km to the north and within the St. Lawrence Lowlands. This suggests the Albany Pine Bush dune field formed after any winds associated with Laurentide ice sheet had shifted northward. Parallel dune limbs indicate a single prevailing wind direction and their formation over a short time interval. These observations support previous studies indicating dunes are composed of immature sediments and traveled only a short distance from their source. Isolated features are probably partially preserved remains of dunes in developed residential areas. The origin of sand pits is uncertain but probably anthropogenic.