Nutrients influence on Miocene carbonate factories

The aim of this work is to improve our knowledge of nutrients influence in the fossil record of the Miocene. The studied succession were analyzed trough a multidisciplinary approach encompassing paleontology, sedimentology and geochemistry in order to extract information and disclose the existing relation between fossil skeletal assemblages and nutrient abundance. The Miocene has been a turning point for our Planet evolution. During the Miocene the ocean circulation finally become comparable to the present-day situation. A further decrease in temperature brought climatic condition very close to those of the present. Land and marine life were fairly modern and many present-day ecosystems arose in the Miocene. Lower Miocene is also the oldest period in which the principle of taxonomic uniformity can be safely applied. Miocene is the first Epoch of modern Earth and therefore is the perfect setting to study, on a geological time frame, ecological processes and draw conclusions useful in the comprehension of present-day ecosystems. While many other works have tried to analyzed productivity and nutrient fluctuation in deep water sediments, this is one of the first attempt to approach the problem in shallow water setting. Shallow water biota is deeply influenced by variation in nutrient supply and may record these differences. Even thought chemical analyses may be sizebly biased by diagenesis in coarse-grained shallow-water sediment, with certain techniques and accurate combination of different groups of data it is possible to unveil precious information. The studied succession of the Pietra da Cantoni Limestone Group of the Tertiary Piedmont Basin and of the Sandy Molasse Unit of the Sommières Basin are both of Burdigalian age and they were close-by during the Miocene. They were also both characterized by an heterozoan skeletal assemblage and the abundance of coralline algae and taxa of suspension-feeder. They were chosen to minimize climatic and geographical variability and to concentrate over productivity. Nutrient-rich waters have left a clear imprint on the fossil record by influencing the marine biota. These traces may be brought to light and used to improve our knowledge of the nutrient cycle of the Earth.