Stable isotopes of sediment core MD85-668

A high-quality delta18O record has been obtained from a deep sea core in the Somali Basin in a water depth of 4020 m, well below the foraminiferal lysocline, by analyzing bulk sediment instead of picked foraminifera. In some areas this may be a valuable tool for extending the applicability of the delta18O stratigraphy, for obtaining data by a less labor-intensive procedure, and for conserving valuable core material. Additionally, we draw attention to the need for more data on delta13C in bulk carbonate if we are to fully utilize the ocean delta13C record either in relation to long-term global carbon budget, or in relation to changes in carbon cycling in the ocean and its effect on atmospheric pCO2.