Dynamics of a northern barrier beach: Nauset Spit, Cape Cod, Massachusetts

摘要

Quantitative analysis of historical shoreline (ocean and bay) and coastal environments (dune, salt marsih, shrub, washover, and sandy beach) change data for Nauset Spit, Cape Cod, Massachusetts are described in this paper. There are marked differences in the relative role of the landward sediment transport processes along the Nauset barrier chain. In general, the barriers have been narrowing during thi; past century, and bayshore accretion has not been equal to ocean shoreline erosion rates. Inlets are largely responsible for bayside sedimentation, whereas over-wash is not effective in maintaining width until the barrier sllims considerably. While salt marshes form on intertidal washover deposits, the vast expanse of barrier-related marshes have developed atop of flood-tidal deltas, and overwash subsequently has buried and killed the marshes. Therefore, massive washovers eventually become the sites of new dunes, often at trie expense of marshes in the cyclic events of barrier evolution.