A revised high-resolution oxygen-isotope chronology for ODP-668B: implications for Quaternary biomass burning in Africa

We present a high-resolution oxygen-isotope chronology to Stage 13 for core ODP-668B, Sierra Leone Rise, east equatorial Atlantic. Observed variations in the abundance of oxidation resistant elemental carbon (OREC) in this core are reinterpreted in the light of this revised chronology, which differs significantly from that proposed by Bird and Cali [Nature 394 (1998) 767]. Peaks in OREC abundance are considered to be related to periods of intense biomass burning in adjacent areas of sub-Saharan Africa during periods of rapid climate change. OREC peaks do not occur during peak glacial times possibly due to low fuel loads and generally cool/dry climate. The most recent OREC peak in the current interglacial period is not unique, as a peak of similar intensity occurs at the peak of the Stage 7 interglacial. Therefore, an anthropogenic origin for the most recent peak cannot be unequivocally established.