10. MICROFACIES OF SOME SEDIMENTS FROM THE WESTERN NORTH ATLANTIC: PALEOCEANOGRAPHIC IMPLICATIONS (LEG 44 DSDP)1

We characterized the microfacies of sediments encountered during Leg 44 on the basis of coarse fraction mineralogy (Φ> 125 µ.m), silt mineralogy (63>Φ>20 µm), clay mineralogy (</><2 µm), silt and clay particle size distributions, and calcium carbonate contents. Secondly we attempted to tentatively correlate microfacies changes with major oceanographic events which have affected the sedimentary processes along the continental margin of North America.Because part of the stratigraphic column was not recovered (no Pliocene and Oligocene, and reduced Pleistocene and Barremian sections), and because of the fairly large sampling intervals our results are far from complete and exhaustive. Some important results, however, concerning the evolution of the oceans since Barremian time were obtained. From Albian to Upper Cretaceous the deep part of the Blake-Bahama Basin has been the site of deposition of sediments bearing organic matte