Long extending the record on continental margins Quaternary stratigraphy

Abstract

Thick sedimentary successions on continental margins preserve a high-resolution record of environmental change on the adjacent continent. Commonly, the stratigraphic succession is well-imaged by seismic-reflection profiles but lacks direct sampling by wells or boreholes. The well-dated 100 ka cyclicity of later Quaternary sea-level change can in many situations be used to infer a chronology for continental margin sediment successions that are not directly sampled. This paper presents a series of case studies that illustrate the successes and limitations of such techniques. Extreme lowstands of sea level that result in coastal or deltaic progradation, the cutting of gullies of the slope, or the incision of river valleys across the shelf are the most useful chronological markers.