Age determination of sediment cores from the North Atlantic Ocean

The clay mineralogy of four 5.5- to 13.5-m-long cores sampled between 45° and 60°N in the North Atlantic Ocean has been investigated at high latitudes within a well-constrained chronostratigraphic scale. Cross-correlation spectral analyses have been performed on both clay mineral and delta18O planktonic records. Detrital clay minerals display strong signals which are coherent with the delta18O record, within the three main Milankovitch frequency bands (eccentricity, obliquity, and precession). The climatic control on clay mineral sedimentation largely depends on the latitudinal location of the sediment cores. The 100,000-year signal occurs as a uniformly acting factor, whereas the 41,000-year signal dominates clay sedimentation at high latitudes and the 23,000-year signal dominates at midlatitudes. We suggest that the latitudinal variations of the orbital forcing on the detrital clay mineral distribution in the North Atlantic Ocean not only result from climatic control of the intensity of physical and chemical weathering, but also from latitudinal control on the detrital clay supply linked to influences of the high-latitude wind-driven and midlatitude ocean-driven transportation processes, respectively.