Eolian components in Cretaceous and Tertiary North Atlantic sediments

Abstract

Abstract Approximately 100 pelagic Deep Sea Drilling Project sediment samples have been examined to outline the history of dust supply to the North Atlantic. Samples were Early Cretaceous to late Miocene. With the exception of a few samples, the quartz is fine grained (means 9.00-7.34Phi , 2-6mu m), moderate to well sorted and negatively skewed. By comparing the grain-size distributions with those of airborne dust it is concluded that most of the sampled quartz is eolian. The clay minerals in the samples are also presumed mainly wind-blown throughout the Tertiary and Cretaceous, though an apparently diagenetic assemblage prevails in the Eocene samples. The clay mineralogy differs between one side of the Atlantic and the other, and on several time planes the quartz becomes coarser towards both the African and American continents. Eolian input from both continents is tentatively suggested. Furthermore, the zone of maximum dust input appears to have remained in latitudes 20-30 degrees N since the Early Cretaceous.--Modified journal abstract.