8. Deep ocean sediments and dating the past

Abstract

Deep ocean sediments, dominated by the shells of tiny marine organisms, form an unbroken record of environmental change that spans the entire Quaternary. In 1968, the Deep Sea Drilling Project began to collect hundreds of long sediment cores. ‘Deep ocean sediments and dating the past’ shows that two aspects of the marine sediment record proved to be particularly instructive for reconstructing the history of the terrestrial ice sheets: the isotope chemistry of foram shells and the incidence of ice-rafted debris (IRD). Ground-breaking work by Nick Shackleton and Neil Opdyke and the identification of periods of ice sheet instability — Heinrich Events — shed new light on ice sheet–ocean–atmosphere interactions and ice age climate change.