Chemistry and microscopy of atmospheric particulates at Delos (Cyclades–Greece)

In order to explain the weathering mechanisms of marbles and granites used in the monuments of Delos archaeological site (Cyclades–Greece), research has characterized atmospheric particles and defined stones petrophysical properties. In this paper, characteristics of atmospheric particulates are presented from sampling in March and July 1995. Air was filtered through Nuclepore membranes and particles were analysed by X-Ray Fluorescence (XRF), Analytical Scanning Electron Microscopy (ASEM) and Analytical Transmission Electron Microscopy (ATEM). XRF measurements show that Na, Cl and S have the highest concentrations. According to geochemical calculations, it appears that S is constituted in major part by excess S, anthropic in origin. Individual analyses by ASEM allow the classification of particles 1 μm in five categories: marine, terrigenous, mixture of marines and terrigenous and undetermined species, anthropogenic and biogenic. ATEM study concerned S-bearing fine particles ( 2 μm). Two atmospheric sources able to participate in marbles and granites weathering have been identified: a natural source of marine salts (halite mainly) the production of which depends on wind speed; an anthropic source (high excess sulphur concentrations) which indicates a regional to remote pollution.