ABSTRACT OF THESIS The Role and Magnitude of Eolian Processes in the Barrier Island Environment By James M. McCluskey, Ph.D. Dissertation Director: Dr. Karl F. Nordstrom This study analyzes the role and importance of eolian and overwash processes in the development of barrier island morphology and in the mechanisms of barrier island migration within different temporal and spatial frames of reference and under different equilibrium conditions at Fire Island, New York. An observed sediment budget is presented for a 42-day period to depict the magnitude and routing of blown sediments during the steady time frame. Information for this budget is based upon the mass accumulation of sediment in vertical eolian sediment samplers emplaced on the ocean beach, primary and secondary dune fields, backbarrier, bayside beach, blowouts, and overwash fans. This data set is used to calibrate an eolian sediment budget for 1980 which is calculated from a modification of the Bagnold formula applied to local wind records. The volumes of sediments associated with beach, eolian, overwash, barrier platform, and marsh deposits are determined for the subaerial portion of the island during the graded time frame. The relative contribution of eolian and overwash sediments varies along the coast. Eolian sediments are dominant over overwash sediments where the littoral sediment budget is positive and the foredune ridge attains a height that prohibits widespread overwash penetration. The volume of eolian deposits is greater than the volume of overwash deposits in the central reach of the island and accounts for 21% of the total volume of the island. Overwash deposits are present in greater volumes than are eolian deposits in the western and eastern reaches of the island and account for 47% and 26% respectively of the total island volume. Sediment is transported landward across the barrier by inlet processes. Neither eolian nor overwash processes contribute to the landward migration of the island. During the cyclic time frame the eastern portion of the island is migrating landward by continuous shoreface retreat, whereas the central and western sections are being drowned-in-place. The results of the study indicate that several different process-response mechanisms are active simultaneously in shaping the morphology and migrational patterns of the island.