LATITUDINAL CONTROL OF ASTRONOMICAL FORCING PARAMETERS ON THE HIGH-RESOLUTION CLAY MINERAL DISTRIBUTION IN THE 45-DEGREES-60-DEGREES N RANGE IN THE NORTH-ATLANTIC OCEAN DURING THE PAST 300,000 YEARS

The clay mineralogy of four 5.5- to 13.5-m-long cores sampled between 45 degrees and 60 degrees N in the North Atlantic Ocean has been inves tigated at high latitudes within a well-constrained chronostratigraphi c scale. Cross-correlation spectral analyses have been performed on bo th clay mineral and delta(18)O planktonic records. Detrital clay miner als display strong signals which are coherent with the delta(18)O reco rd, within the three main Milankovitch frequency bands (eccentricity, obliquity, and precession). The climatic control on clay mineral sedim entation largely depends on the latitudinal location of the sediment c ores. The 100,000-year signal occurs as a uniformly acting factor, whe reas the 41,000-year signal dominates clay sedimentation at high latit udes 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 weath ering, but also from latitudinal control on the detrital clay supply l inked to influences of the high-latitude wind-driven and midlatitude o cean-driven transportation processes, respectively.