General considerations and highlights of low-lying coastal zones: passive continental margins from the poles to the tropics

Abstract

AbstractThis Special Publication presents 23 papers that examine comparable, predominantly siliciclastic coastal zones of low-lying passive trailing-continental margins (primarily east Americas) from polar areas to the equator. The objective is to establish similarities and major differences among them. This introductory paper outlines major contributions of the various papers, but will also highlight coastal differences and briefly add information not fully treated by others. This is done in three parts: (a) some basic concepts are stressed, such as the importance of ‘coastal zone’ (total landscape) in the north–south comparison and the variable climates; (b) a review is made of the component materials of the coasts, such as difference in sediments owing to source rocks, weathering and geological history (glaciations), and in flora and fauna such as burrowing organisms; and (c) a few classical examples are reported from warm zones, such as Galveston Island and the Sapelo Island marshes, but the focus is on less well-known environments of cold areas – those most impacted by climate change. Each component of the coastal zone can develop diagnostic characteristics, but the entire assemblage of sedimentary and biological features is what uniquely defines present environments and allows identification of ancient coastal zones.