SEDIMENTARY PROCESSES AND THE CREATION OF THE STRATIGRAPHIC RECORD IN THE LATE QUATERNARY NORTH-ATLANTIC OCEAN

The primary difficulty in the interpretation of the stratigraphic record is that a multiplicity of sedimentary processes, some producing similar effects, are responsible for it. We seek to unravel the effects of the more important processes through analysis of sedimentary properties. The effects to be unravelled are those relating to pelagic input (vertical flux) due to organic productivity, wind-blown dust, ice-rafting and volcanic ash; to horizontal flux in turbidity currents, debris flows, and nepheloid layers caused by the reworking of sea-bed sediments by internal waves and bottom currents; and to degradation of the record by dissolution, oxidation and mixing of components. Contrasting regions of the North Atlantic are used to show the effects of bottom currents, ice-rafting, wind and productivity on sediments. Applications to estimates of changes in bottom currents, productivity and carbon sequestration in the N.E. Atlantic over the past 30 ka are given.