A record of glacial interglacial alternations in Pleistocene sediments offNew Jersey expressed by clay mineral, grain-size and magnetic susceptibility data

Clay mineral, grain-size and magnetic susceptibility measurements have been performed on a high resolution sampling of Pleistocene clayey silts and si lty clays drilled at ODP Site 902 (Hole D) located on the upper slope off N ew Jersey (NW Atlantic). The combination of data from different techniques, and their comparison with delta(18)O and Gamma-Ray Attenuation Porosity Ev aluator (GRAPE) data, allow us to clearly distinguish between sediments dep osited during glacial and interglacial cycles. Glacial sediments are poorly -sorted, rich in either clay or sand, and characterized by the abundance of chlorite and high magnetic susceptibility values. In contrast, interglacia l sediments are well-sorted, silt-dominated and poor in chlorite. The Hudso n River and its tributaries draining the Appalachian Highlands appear to co nstitute the perennial sources of the detrital input including quartz, feld spars, amphibole and a clay fraction dominantly composed of illite, random mixed-layers and kaolinite. During glacial stages, the terrigenous sediment ation was enhanced by additional input of chlorite from glacial erosion in Northeastern America. The variations in chlorite amounts supplied to the oc ean were probably controlled by the ice-sheet advances and retreats. These variations are quantified by the kaolinite/chlorite ratio (K/C) which const itutes a reliable marker of glacial and interglacial influences on the terr igenous sedimentation. (C) 1999 Elsevier Science B.V. All rights reserved.