Uranium Geochemistry of Italian Travertines and Calcareous Tufas: Exploring the Relationship between Carbonate Deposition, Groundwater Circulation and Subsurface Geology

A database consisting of 163 data on the uranium content and 234U/238U initial activity ratio 15 Italian travertine calcareous tufa sites was created using from relevant literature. Using a graphical method, were interpreted considering U geochemistry in natural environments as well geological, hydrogeological hydrogeochemical settings each site. The appear to be affected by different factors, such availability aquifer rocks, redox state waters, alpha-active radionuclide recoil phenomenon. allow identification four groups travertines/tufas: (i) those precipitated circulating groundwater, with short/fast flow path, volcanic rocks high content; (ii) long, deep path carbonate/evaporite formations relatively low (iii) cold waters associated riverine systems, which are characterized oxidizing conditions fed high-discharge springs recharged carbonate aquifers. fourth group represents intermediate situations frequently occurring due mixing results suggest an interpretative model that might contribute paleo-environmental reconstruction fossil depositing systems.