History of mesozoic and cenozoic sediment fluxes to the North Atlantic Ocean

This history of the Mesozoic and Cenozoic depositional paleoenvironments of the North Atlantic Ocean has been written based on a detailed analysis of all accessible deep-sea drill sites, of temporal and spatial distributions of major pelagic sediment facies, of hiatuses, of bulk sediment accumulation rates, and of concentrations and fluxes of the most important deep-sea sediment components. Spatial patterns of theses variables have been evaluated based on data plotted into palinspastic maps, which are tracing stepwise for 30 time slices the paleophysiographic evolution of the zonal North Atlantic and its epicontinental seas. The depositional history of the North Atlantic can be subdivided into three major phases when processes controlling sediment input and sediment distribution in this ocean basin differed: a) A Late Jurassic and Early Cretaceous phase: Clastic terrigenous sediment components as well as biogenic pelagic ones accumulated rapidly under highly productive surface water masses over the entire ocean basin. b) A mid- to Late Cretaceous to Early Miocene phase: Generally relatively little terrigenous and pelagic biogenic sediment reached the North Atlantic ocean floor. c) A Middle Miocene to Recent phase: Accumulation rates of biogenic and terrigenous deep-sea sediment components increased dramatically up to Quaternary times, rates of hiatus formation and henceforth the intensity of deep-water circulation seemed to have decreased. Reconstructions of the paleodepth distributions of hiatuses have revealed maxima of hiatus occurrence in the western main North Atlantic basin in two depth levels, namely close to 5 km and 2,2-4 km paleodepth, but in the eastern basin only in one level at 1,2-1,8 km paleodepth. Continued sea floor spreading had an important impact on the depositional environment in this ocean.