ABSTRACT
The Ocean has historically been recognized as an essential regulator of climate in our planet, playing a significant role in different processes like generation of wind fields and storms, changes in biogeochemical balances, global circulation and heat fluxes. Biogeochemical signatures preserved in ancient sedimentary rocks provide clues to identify the magnitude, distribution trend and evolution of main seawater chemical parameters, and so the reconstruction of palaeo- environmental conditions within the Primitive Ocean is possible. In the modern oceans areas of high organic productivity are predominantly localized within Mediterranean, marginal and shelf seas, and the ratio of the surface of such seas to the global ocean surface is ~1:30; nevertheless, during the peak of the Cretaceous transgression this ratio was at least 1:6. The Quaternary is a period characterized by strong climate variability in relatively short periods, and this fact has also driven to variations in ocean conditions.
