Ocean stability during the mid-Pliocene warmth based on Calcareous nannofossils in Site 610, North Atlantic Ocean

Abstract:

We studied the calcareous nannofossil assemblages of the sequence of middle Pliocene, DSDP Site 610, North Atlantic Ocean. This intervals are correlated to mid-Pliocene warmts (Raymo et al., 1996), and characterized by abundantly occurrence of warm water species.

The studied interval of Site 610 is situated between MG8 and G7 of marine isotope stages based on nannofossil biostratigraphy. We studied maximum size of Reticulofenestra species and the productivity of coccolith which indicates the stability level of surface ocean in this interval. The productivity shows the presence of lowest peak in MIS KM2. The high productivities are recognized in the stage of MIS M2 and G20 (Fig. 1). The variability of the maximum size of Reticulofenestra in this interval shows the negative correlation with coccolith productivity. As the lower productivity and the occurrence of large size Reticulofenestra indicate the oligotrophic and stable sea surface condition, the results shows the development of stable and low nutrient sea surface conditions during MIS M2 and G20 in the North Atlantic Ocean.