into the origin of the Cenozoic cooling trend

Abstract. Here we present a high-resolution cyclostratig-raphy based on X-ray fluorescence (XRF) core scanning data from a new record retrieved from the tropical west-ern Atlantic (Demerara Rise, ODP Leg 207, Site 1258). The Eocene sediments from ODP Site 1258 cover magne-tochrons C20 to C24 and show well developed cycles. This record includes the missing interval for reevaluating the early Eocene part of the Geomagnetic Polarity Time Scale (GPTS), also providing key aspects for reconstructing high-resolution climate variability during the Early Eocene Climatic Opti-mum (EECO). Detailed spectral analysis demonstrates that early Eocene sedimentary cycles are characterized by pre-cession frequencies modulated by short (100 kyr) and long (405 kyr) eccentricity with a generally minor obliquity com-ponent. Counting of both the precession and eccentricity cy