GARNET PROVENANCE STUDY OF BEACH SANDS FROM SANDY HOOK AND CAPE MAY, NEW JERSEY

The provenance of New Jersey beach sand garnets can be used to evaluate sediment transport pathways from source area to different portions of the NJ coastline. Garnet grains were selected due to their relative abundance in NJ beach sands, resistance to weathering, and distinctive chemical compositions. This preliminary study focuses on the provenance of beach sands from Sandy Hook and Cape May. These locations were selected because they represent the northernmost and southernmost points along NJ’s Atlantic barrier coastline, respectively, and therefore might provide the greatest potential for compositional differences. Likely source regions for Sandy Hook garnets include the Adirondacks and the New England province with the Hudson River and Connecticut River watersheds as two possible transport pathways combined with glacial transport and deposition. Cape May garnets potentially are derived from the NJ and PA piedmont and highlands provinces via the Delaware River. Initial results from X-ray diffraction reveal Sandy Hook garnets to be mainly of almandine composition with a lower abundance of garnets with pyrope composition. The garnets from Cape May have yet to be classified. Future comparison of NJ garnet compositions to those from potential source regions will help to distinguish garnet provenance.