Quaternary coastal morphology and sea-level changes—an introduction

Few things remain static in natural systems and perhaps no better illustrated than by changes in the level of the ocean surface with respect to the land over Quaternary timescales. The position of sea level (ultimate base level) and changes of sea level over geological timescales represent important controls in the evolution of coastal environments, and as an agent of profound geomorphological and environmental change in adjacent landscapes. Sea level determines the lower limit of continental denudation, to which fluvial, aeolian and other weathering and erosional processes may lower the landscape. Sea level also determines the volume and nature of terrestrially derived sediment deposited within coastal environments, sediment sourced from the inner continental shelf and acts as a major control in the formation of sedimentary carbonates. The significance of relative sea-level changes has long been recognized across the various sub-disciplines of the Earth sciences and the historical development of the broader discipline has, in part, occurred in unison with increased understanding of changes in relative sea level, as well as the physical processes responsible for these changes. Since the early 1970s, successive International Geological Correlation Projects (IGCP), funded by UNESCO and the International Union of Geological Sciences (IUGS), examined Quaternary sea-level changes and their environmental significance. Since their inception in 1974, IGCP projects devoted to the study of sealevel changes include, Project 61 Sea-level change during the last deglacial hemicycle directed by Arthur L. Bloom (1974–1982), Project 200 Sea-level correlation and applications directed by Paolo A. Pirazzoli (1983–1987), Project 274 Coastal evolution in the Quaternary directed by Orson van de Plassche (1988–1993) and Project 367 Late Quaternary coastal records of rapid change— application to present and future conditions directed by David B. Scott (1994–1998). This special issue of Quaternary Science Reviews comprises a selection of papers presented at the final