Atmospheric mineral dust in ice cores: application of Neutron Activation and Synchrotron Radiation X-ray fluorescence

It is estimated that several million of tons of mineral dust are constantly transported in the atmosphere. Such a massive burden has a great influence on many dynamics of our planet, from biogeochemistry, to radiative processes, to sedimentology. An important aspect concerns the tight relationship between dust and climate, at different spatial and temporal scales. Ice cores allowed reconstructing the more detailed and extended records related to atmospheric dust deposition and transport. Measuring the physical and chemical properties of mineral particles, it was possible to understand the influence of climate on the dust cycle and vice versa, i.e. the influence of mineral particles on climate. In this thesis recent advancements about the understanding of the dust cycle in different contexts (Antarctica and the Alps) will be presented. A significative part of the work is dedicated to the development of new methods for the geochemical investigation of ice cores. Applying these new methods and other established ones, it was possible to draw new insights about the provenance of dust during different climatic periods in Antarctica, focusing on the different response associated to local and distal dust sources in relation to climate changes and on the effect of climate on dust geochemistry. In particular new evidences concern dust properties during Holocene, when dust deposition in Antarctica reaches its lower levels. Turning the attention to the Alps it was possible to highlight the influence of anthropic emission on dust composition, with anomalous values for many elements related to industrial and domestic activities. In addition the construction of a high resolution record allowed studying in detail the phenomenon of Saharan dust deposition in Southern Europe, a process with many and different environmental consequences.